Researcher Profile and Settings

Master

Affiliation (Master)

• Graduate School of Humanities and Human Sciences　Division of Human Sciences　Department of Behavioral Science

Affiliation (Master)

• Graduate School of Humanities and Human Sciences　Division of Human Sciences　Department of Behavioral Science

researchmap

Profile and Settings

Degree

• Ph.D in physics (Biophysics)（The University of Tokyo）

Profile and Settings

• Profile

  Ph.D in Physics
  The University of Tokyo

• Name (Japanese)

  Taiki

• Name (Kana)

  Takahashi

• Name

  200901089985802300

Alternate Names

https://twitter.com/tweet_taiki

Achievement

Research Interests

• 情報科学（量子情報論理）   応用数学   Neurolaw   Sociophysics   Neuroeconomics   

Research Areas

• Humanities & social sciences / Cognitive sciences / Neuroeconomics, Quantum Decision Theory

Education

•        - 2001  The University of Tokyo
•        - 2001  The University of Tokyo  Physics Graduate School, Division of Science  Ph.D
•        - 1998  The University of Tokyo
•        - 1998  The University of Tokyo  Physics Graduate School, Division of Science  Master of Science
•        - 1996  The University of Tokyo  Faculty of Science  Department of Physics
•        - 1996  The University of Tokyo  Department of Physics  Bachelor of Science
•        - 1992  開成高等学校 卒業

Committee Memberships

• 2019/04 - Today   CHAIN center for human nature, AI and neuroscience   joint faculty

Awards

• 2012/12 行動経済学会 奨励賞
  
• 2007 Best paper award (Association for Neuropsychoeconomics)
  
• 2005 北海道心理学会 論文賞
   

  受賞者: 高橋 泰城
• Best paper award (Association for Neuropsychoeconomics)
   

  受賞者: Takahashi Taiki

Published Papers

• Application of the symbolic regression program AI-Feynman to psychology.

  Masato Miyazaki, Ken-Ichi Ishikawa, Ken'ichiro Nakashima, Hiroshi Shimizu, Taiki Takahashi, Nobuyuki Takahashi

  Frontiers in artificial intelligence 6 1039438 - 1039438 2023 [Refereed][Not invited]
   

  The discovery of hidden laws in data is the core challenge in many fields, from the natural sciences to the social sciences. However, this task has historically relied on human intuition and experience in many areas, including psychology. Therefore, discovering laws using artificial intelligence (AI) has two significant advantages. First, it makes it possible to detect laws that humans cannot discover. Second, it will help construct more accurate theories. An AI called AI-Feynman was released in a very different field, and it performed impressively. Although AI-Feynman was initially designed to discover laws in physics, it can also work well in psychology. This research aims to examine whether AI-Feynman can be a new data analysis method for inter-temporal choice experiments by testing whether it can discover the hyperbolic discount model as a discount function. An inter-temporal choice experiment was conducted to accomplish these objectives, and the data were input into AI-Feynman. As a result, seven discount function candidates were proposed by AI-Feynman. One candidate was the hyperbolic discount model, which is currently considered the most accurate. The three functions of the root-mean-squared errors were superior to the hyperbolic discount model. Moreover, one of the three candidates was more "hyperbolic" than the standard hyperbolic discount function. These results indicate two things. One is that AI-Feynman can be a new data analysis method for inter-temporal choice experiments. The other is that AI-Feynman can discover discount functions that humans cannot find.
• A balance for fairness: fair distribution utilising physics.

  Song-Ju Kim, Taiki Takahashi, Kazuo Sano

  Humanities and Social Sciences Communications 8 (131) 2021/05 [Refereed][Not invited]
  
• Contributions of Science of Free Will to Neuroecocnomics and Quantum Decision Theory

  Taiki Takahashi

  A Genealogy of Self-Interest in Economics 221 - 234 2021 [Refereed]
  
• Editorial: Discounting Models in Behavioral Health Economics and Quantitative Health Psychology.

  María José Muñoz Torrecillas, Salvador Cruz Rambaud, Taiki Takahashi

  Frontiers in public health 9 658808 - 658808 2021 [Refereed]
  
• A New Analysis on Self-Control in Intertemporal Choice and Mediterranean Dietary Pattern.

  Brian C Howatt, María José Muñoz Torrecillas, Salvador Cruz Rambaud, Taiki Takahashi

  Frontiers in public health 7 165 - 165 2019 [Refereed][Not invited]
   

  This paper completes Muñoz Torrecillas et al. (1) results and conclusions investigating the relationship between adherence to healthy dietary habits, specifically the Mediterranean Diet (hereinafter, MD), and impulsivity in intertemporal choices. Impulsivity can be defined as the strong preference for small immediate payoffs over larger delayed payoffs, and in the original study this behavior was captured by the parameter k (discount rate of the hyperbolic discount function), calculated using an automated scoring mechanism. Adherence to MD was measured by the KIDMED index and then grouped into three levels: high, medium, and low. While the authors observed that individuals in the high adherence group had the shallowest discounting and individuals in the low adherence group had the steepest discounting, the data were not statistically analyzed in depth. Therefore, the purpose of the present paper is to propose a preliminary quantitative model for this relationship and evaluate its significance. Tests revealed a significant interaction between adherence to MD and magnitude of delayed rewards when predicting discount rates. Specifically, the degree to which impulsivity decreases as adherence to MD increases is strongly influenced by delayed rewards of smaller magnitude. These findings are consistent with the authors' claims that healthy dietary habits may be closely linked with greater self-control when payoffs are small, and thus warrant further examination. The results do not indicate causality though, so future studies could also investigate the directions of this relationship as a means of developing behavioral interventions.
• Quantitative Cross-Cultural Similarities and Differences in Social Discounting for Gains and Losses.

  Sarah E Stegall, Tyler Collette, Takuji Kinjo, Taiki Takahashi, Paul Romanowich

  Frontiers in public health 7 297 - 297 2019 [Refereed][Not invited]
   

  Social discounting is when resource allocation decreases as social distance increases. Studies fitting different quantitative models to social discounting data have shown that a q-exponential function based on Tsallis' statistics best fits loss data, whereas a hyperbolic power function best fits gain data. However, a social discounting sign effect, where losses are discounted less than equivalent gains, has not been consistently found. This study fit four different quantitative social discounting models to gain and loss data for 40 United States (US) participants. We compared quantitative model fits to previous studies collected with Japanese and German participants to determine if (1) different quantitative social discounting models best fit loss and gain data, (2) US participants discounted less gains than Japanese participants, but not losses, and (3) US participants showed the sign effect. Results showed that the q-exponential function and the hyperbolic power function best fit median loss and gain data, respectively. There were no significant absolute differences between cultures for gains or losses, and US participants showed a robust sign effect. While most results for US participants were consistent with previous data, future cross-cultural social discounting studies are needed that manipulate sign as well as reward magnitude to determine best quantitative model fits. Social discounting results are also discussed in relation to their application to important health behaviors such as smoking and obesity.
• Performance in Multi-Armed Bandit Tasks in Relation to Ambiguity-Preference Within a Learning Algorithm

  Song-Ju Kim, Taiki Takahashi

  Frontiers in Applied Mathematics and Statistics Frontiers Media SA 4 27  2018/07/25 [Refereed]
  
• Impatience and Inconsistency in Intertemporal Choice: An Experimental Analysis

  María José Muñoz Torrecillas, Taiki Takahashi, Jesús Gil Roales-Nieto, Salvador Cruz Rambaud, Zaida Callejón Ruiz, Blas Torrecillas Jover

  Journal of Behavioral Finance 19 (2) 190 - 198 1542-7579 2018/04/03 [Refereed][Not invited]
   

  In this article the experiment carried out by Takahashi et al. [2009] is replicated to analyze the influence of culture, gender, origin (urban or rural), and socioeconomic level on the impulsivity and consistency of decision-making processes concerning monetary gains and losses. The results indicate that Spanish students show inconsistency, and more impulsivity over gains (i.e., more impatience, as they discount delayed outcomes more rapidly) than do Japanese and American students. Additionally, participants from urban areas show more impatience over gains than do participants from rural ones, women are more impatient than men are over losses, and participants of different socioeconomic levels show differences in their impulsivity parameters.
• Behavioral Economics of Addiction in the Age of a Super Smart Society: Society 5.0

  TAKAHASHI Taiki

  Oukan (Journal of Transdisciplinary Federation of Science and Technology) 12 (2) 119 - 122 1881-7610 2018 [Refereed]
   

  In behavioral economics, violation of rationality in human judgment and decision making has been investigated. In neoclassical economics, on the contrary, almost all human behavior (in- cluding addiction) has been assumed to be rational. Recent developments in Neuroeconomics have revealed neural foundations for human judgment and decision making. Cyber technologies offer new risks for new types of addiction (e.g., internet addiction, online video game addiction, and smartphone addiction); while these technologies can potentially offer new intervention methods for the treatment of addiction. In this review, current findings in the studies of addiction in the age of “super smart society” (i.e., societies highly digitized and connected via SNSs) are introduced and future directions are discussed.
• Self-Control in Intertemporal Choice and Mediterranean Dietary Pattern.

  María J Muñoz Torrecillas, Salvador Cruz Rambaud, Taiki Takahashi

  Frontiers in public health 6 176 - 176 2018 [Refereed][Not invited]
   

  Background: The Mediterranean Diet (hereinafter MD) is considered a healthy dietary pattern. Adherence to this pattern can be assessed by means of the KIDMED test by which individuals are assigned an index and classified into three groups of adherence to MD: high, medium, and low. In addition, impulsivity or impatience in intertemporal choice has been defined as a strong preference for small immediate rewards over large delayed ones. Objective: This study examines the relationship between dietary habits, specifically Mediterranean dietary pattern, measured by the KIDMED index, and the exhibited impatience in intertemporal choices, by means of the parameter k (discount rate of the hyperbolic discount function). Methods: A sample of 207 university students answered a questionnaire based on two tests: the KIDMED test, to assess the degree of adherence to MD, and an intertemporal choice questionnaire, to assess impatience or impulsivity. Individuals were grouped depending on their KIDMED score and then the discount rate or impulsivity parameter was calculated for each group. Results: Discount rates were inversely related to the degree of adherence to MD. The values of overall k were 1.53, 1.91, and 3.71% for the groups exhibiting high, medium and low adherence to MD, respectively. We also found higher k-values for larger rewards (magnitude effect) in the three groups. Conclusion: High adherence to MD is related to less steep time discounting, which implies less impulsivity (more self-control) or lower discount rates. Conversely, low adherence to MD is related to steeper time discounting, which implies impulsivity or higher discount rates. These findings could be used to identify the target population where policy interventions are needed in order to promote healthier diet habits.
• A note on the roles of quantum and mechanical models in social biophysics.

  Taiki Takahashi, Song-Ju Kim, Makoto Naruse

  Progress in biophysics and molecular biology 130 (Pt A) 103 - 105 2017/11 [Refereed][Not invited]
   

  Recent advances in the applications of quantum models into various disciplines such as cognitive science, social sciences, economics, and biology witnessed enormous achievements and possible future progress. In this paper, we propose one of the most promising directions in the applications of quantum models: the combination of quantum and mechanical models in social biophysics. The possible resulting discipline may be called as experimental quantum social biophysics and could foster our understandings of the relationships between the society and individuals.
• Can quantum approaches benefit biology of decision making?

  Taiki Takahashi

  Progress in biophysics and molecular biology 130 (Pt A) 99 - 102 2017/11 [Refereed][Not invited]
   

  Human decision making has recently been focused in the emerging fields of quantum decision theory and neuroeconomics. The former discipline utilizes mathematical formulations developed in quantum theory, while the latter combines behavioral economics and neurobiology. In this paper, the author speculates on possible future directions unifying the two approaches, by contrasting the roles of quantum theory in the birth of molecular biology of the gene.
• Testosterone promotes either dominance or submissiveness in the Ultimatum Game depending on players' social rank.

  Yukako Inoue, Taiki Takahashi, Robert P Burriss, Sakura Arai, Toshikazu Hasegawa, Toshio Yamagishi, Toko Kiyonari

  Scientific reports 7 (1) 5335 - 5335 2045-2322 2017/07/13 [Refereed][Not invited]
   

  Endogenous testosterone promotes behaviours intended to enhance social dominance. However, recent research suggests that testosterone enhances strategic social behaviour rather than dominance seeking behaviour. This possibility has not been tested in a population whose members are known to vary in social status. Here, we explored the relationship between pre-existing social status and salivary testosterone level among members of a rugby team at a Japanese university, where a strong seniority norm maintains hierarchical relationships. Participants played a series of one-shot Ultimatum Games (UG) both as proposer and responder. Opponents were anonymised but of known seniority. We analysed participants' acquiescence (how much more they offered beyond the lowest offer they would accept). The results showed that, among the most senior participants, higher testosterone was associated with lower acquiescence. Conversely, higher testosterone among the lower-status participants was associated with higher acquiescence. Our results suggest that testosterone may enhance socially dominant behaviour among high-status persons, but strategic submission to seniority among lower-status persons.
• The Q-generalized Probability Weighting Function and the Q-exponential Probability Discounting Function

  Shinsuke Tokuda, Taiki Takahashi

  International Journal of Applied & Experimental Mathematics 2 (1) 2017/04 [Refereed]
  
• Percolation of optical excitation mediated by near-field interactions

  Makoto Naruse, Song-Ju Kim, Taiki Takahashi, Masashi Aono, Kouichi Akahane, Mario D'Acunto, Hirokazu Hori, Lars Thylen, Makoto Katori, Motoichi Ohtsu

  PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIONS 471 162 - 168 0378-4371 2017/04 [Refereed]
   

  Optical excitation transfer in nanostructured matter has been intensively studied in various material systems for versatile applications. Herein, we theoretically and numerically discuss the percolation of optical excitations in randomly organized nanostructures caused by optical near-field interactions governed by Yukawa potential in a two-dimensional stochastic model. The model results demonstrate the appearance of two phases of percolation of optical excitation as a function of the localization degree of near-field interaction. Moreover, it indicates sublinear scaling with percolation distances when the light localization is strong. Furthermore, such a character is maximized at a particular size of environments. The results provide fundamental insights into optical excitation transfer and will facilitate the design and analysis of nanoscale signal-transfer characteristics. (C) 2016 Elsevier B.V. All rights reserved.
• Observed and Normative Discount Functions in Addiction and other Diseases.

  Salvador Cruz Rambaud, María J Muñoz Torrecillas, Taiki Takahashi

  Frontiers in pharmacology 8 416 - 416 2017 [Refereed][Not invited]
   

  The aim of this paper is to find a suitable discount function able to describe the progression of a certain addiction or disease under treatment as a discounting process. In effect, a certain indicator related to a disease decays over time in a manner which is mathematically similar to the way in which discounting has been modeled. We analyze the discount functions observed in experiments which study addictive and other problematic behaviors as well as some alternative hyperbola-like discount functions in order to fit the patience exhibited by the subject after receiving the treatment. Additionally, it has been experimentally found that people with addiction display high rates of discount (impatience) and preference reversals (dynamic inconsistency). This excessive discounting must be correctly modeled by a suitable discount function, otherwise, it can become a trans-disease process underlying addiction and other disorders. The (generalized) exponentiated hyperbolic discount function is proposed to describe the progression of a disease with respect to the treatment, since it maintains the property of inconsistency by exhibiting a decreasing discount rate after an initial period in which the opposite occurs.
• Relationship between Salivary Oxytocin Levels and Generosity in Preschoolers.

  Takayuki Fujii, Joanna Schug, Kuniyuki Nishina, Taiki Takahashi, Hiroyuki Okada, Haruto Takagishi

  Scientific reports 6 38662 - 38662 2016/12/08 [Refereed][Not invited]
   

  This study examined the association between salivary oxytocin (sOT) levels and generosity in preschoolers. Fifty preschoolers played two dictator games (DG) by deciding how to allocate 10 chocolates between themselves and another child, who was either from the same class as the participant (ingroup member), or an unknown child from another class (outgroup member). sOT levels were assessed in saliva collected from the children immediately prior to the DG tasks. While sOT levels were negatively associated with allocations made to both ingroup and outgroup members by boys, among girl sOT levels were positively related to allocations made to ingroup members, and unrelated to allocations made to outgroup members. These results suggest sex differences in the association between salivary oxytocin and generosity.
• Cross-cultural comparisons of delay discounting of gain and loss.

  Keiko Ishii, Lili Gang, Taiki Takahashi

  Neuro endocrinology letters 37 (6) 427 - 432 0172-780X 2016/11 [Refereed][Not invited]
   

  OBJECTIVES: People generally tend to discount future outcomes in favor of smaller but immediate gains (i.e., delay discounting). The present research examined cultural similarities and differences in delay discounting of gain and loss between Chinese and Japanese, based on a q-exponential model of intertemporal choice. METHOD: Using a hypothetical situation, we asked 65 Japanese participants and 51 Chinese participants to choose between receiving (or paying) a different amount of money immediately or with a specified delay (1 week, 2 weeks, 1 month, 6 months, 1 year, 5 years, and 25 years). For each delay, participants completed a series of 40 binary choices for gain or loss. RESULTS: Regardless of cultures, the q-exponential model was the optimal model. Both impulsivity and time-inconsistency were higher for future gains than for future losses. In addition to the cultural similarities, Chinese participants discounted future gains and losses more steeply than did Japanese. In contrast, Japanese participants were more time-inconsistent in delay discounting than were Chinese, suggesting that the reduction in their subjective value depended relatively on delay.
• Detection of Phase Transition in Generalized Polya Urn in Information Cascade Experiment

  Masafumi Hino, Yosuke Irie, Masato Hisakado, Taiki Takahashi, Shintaro Mori

  JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN 85 (3) 0031-9015 2016/03 [Refereed][Not invited]
   

  We propose a method of detecting a phase transition in a generalized Polya urn in an information cascade experiment. The method is based on the asymptotic behavior of the correlation C(t) between the first subject's choice and the t + 1-th subject's choice, the limit value of which, c equivalent to lim(t ->infinity) C(t), is the order parameter of the phase transition. To verify the method, we perform a voting experiment using two-choice questions. An urn X is chosen at random from two urns A and B, which contain red and blue balls in different configurations. Subjects sequentially guess whether X is A or B using information about the prior subjects' choices and the color of a ball randomly drawn from X. The color tells the subject which is X with probability q. We set q is an element of {5/9; 6/9; 7/9; 8/9} by controlling the configurations of red and blue balls in A and B. The (average) lengths of the sequence of the subjects are 63, 63, 54.0, and 60.5 for q is an element of {5/9; 6/9; 7/9; 8/9}, respectively. We describe the sequential voting process by a nonlinear Polya urn model. The model suggests the possibility of a phase transition when q changes. We show that c > 0 (=0) for q = 5/9; 6/9 (7/9; 8/9) and detect the phase transition using the proposed method.
• 20pBU-11 Domino effect in information cascade experiment

  Mori S., Hino M., Hisakado M., Takahashi T.

  Meeting Abstracts of the Physical Society of Japan 一般社団法人日本物理学会 71 2902 - 2902 2189-079X 2016 [Not refereed]
  
• Discounting delayed and probabilistic monetary gains and losses by smokers of cigarettes

  Yu Ohmura, Taiki Takahashi, Nozomi Kitamura

  Behavioral Economics of Preferences, Choices, and Happiness 179 - 196 2016/01/01 [Refereed][Not invited]
   

  Rationale: Nicotine dependence has been associated with impulsivity and discounting delayed/uncertain outcomes. Objectives: This study had two main objectives: (1) to examine the relationship between the number of cigarettes consumed per day and the degree to which delayed and uncertain monetary gains and losses are discounted by smokers, and (2) to determine the relationship between the estimated dose of nicotine intake per day and the degree to which four types of discounting occur. Methods: Twenty seven habitual smokers and 23 never smokers participated in this experiment. They were required to choose between immediate and delayed monetary rewards (or losses), or between guaranteed and probabilistic rewards (or losses). Results: The degree to which delayed monetary gains were discounted was significantly and positively correlated with both the number of cigarettes smoked and the estimated dose of nicotine intake per day. Conversely, there was no relationship between smoking and the remaining three types of discounting. Also, mild smokers in our sample did not differ from never smokers in discounting monetary gains or losses. Conclusions: In general, our results suggest that both the frequency of nicotine self-administration, as well as the dosage, are positively associated with greater delay discounting of gains. One neuropsychopharmacological explanation for this effect is that chronic nicotine intake may induce neuroadaptation of the neural circuitry involved in reward processing.
• Loss of self-control in intertemporal choice may be attributable to logarithmic time-perception

  Taiki Takahashi

  Behavioral Economics of Preferences, Choices, and Happiness 117 - 122 2016/01/01 [Refereed][Not invited]
   

  Impulsivity and loss of self-control in drug-dependent patients have been associated with the manner in which they discount delayed rewards. Although drugs of abuse have been shown to modify perceived time duration, little is known regarding the relationship between impulsive decision-making in intertemporal choice and estimation of time-duration. In classical economic theory, it has been hypothesized that people discount future reward value exponentially. In exponential discounting, a temporal discounting rate is constant over time, which has been referred to as dynamic consistency. However, accumulating empirical evidence in biology, psychopharmacology, behavioral neuroscience, and neuroeconomics does not support the hypothesis. Rather, dynamically inconsistent manners of discounting delayed rewards, e.g., hyperbolic discounting, have been repeatedly observed in humans and non-human animals. In spite of recent advances in neuroimaging and neuropsychopharmacological study, the reason why humans and animals discount delayed rewards hyperbolically is unknown. In this study, we hypothesized that empirically-observed dynamical inconsistency in intertemporal choice may result from errors in the perception of time duration. It is proposed that perception of temporal duration following Weber’s law might explain the dynamical inconsistency. Possible future study directions for elucidating neural mechanisms underlying inconsistent intertemporal choice are discussed.
• Pharmacological and Expectancy Effects of a Low Amount of Alcohol Drinking on Outcome Valuation and Risk Perception in Males and Females.

  Tomokazu Tsurugizawa, Shinsuke Tokuda, Tokiko Harada, Taiki Takahashi, Norihiro Sadato

  PloS one 11 (4) e0154083  2016 [Refereed][Not invited]
   

  The high-dose, alcohol-induced influences on risk perception and loss aversion depend on sex. On the other hand, low-dose alcohol has less effect on risky behavior. However, the effect of low-dose alcohol on subjective valuation of gain or loss and also the effect of placebo (expectancy of alcohol) on risk perception have not been fully investigated. We investigated the effects of low-dose alcohol (0.02 g/100 ml blood alcohol concentration) and placebo effects on subjective risk perception and subjective valuation of uncertain gain and loss in females and males. Participants in the control group and the placebo group were served alcohol-free, wine-flavored beverage and participants of alcohol group were served wine (14% alcohol). The placebo group was not informed that the drink was not alcohol but the control group was informed. Then paper-pencil tasks for subjective risk perception and valuation of gain or loss were performed 45 min after drinking the beverage. The participants were asked to draw the line on a 180 mm scale for each question. The placebo effects as well as the low-dose alcohol effects were observed in subjective valuations of gain or loss. Except for effect of beverages, a gender difference was also observed for subjective likelihood. The females estimated a low-probability loss as more likely and estimated a high-probability gain as less likely than did the males. From the Stevens' law fitting analysis, the placebo, not alcohol, significantly induced the psychophysical effect of the subjective valuation of gain or loss. These results indicate that the psychological effects of expectancy of alcohol (placebo) could be a major factor in changing the subjective valuation of gain or loss over the pharmacological effects of a small amount of alcohol (like a glass of wine). Furthermore, these results also indicate that gender differences should be taken into account when investigating pharmacological or psychological effect on decision-making.
• Detection of Non-self-correcting Nature of Information Cascade

  Shintaro Mori, Masafumi Hino, Masato Hisakado, Taiki Takahashi

  PROCEEDINGS OF ECCS 2014: EUROPEAN CONFERENCE ON COMPLEX SYSTEMS 1 - 10 2016 [Refereed][Not invited]
   

  We propose a method of detecting non-self-correcting information cascades in experiments in which subjects choose an option sequentially by observing the choices of previous subjects. The method uses the correlation function C(t) between the first and the t + 1th subject's choices. C(t) measures the strength of the domino effect, and the limit value c = lim(t ->infinity) C(t) determines whether the domino effect lasts forever (c > 0) or not (c = 0). The condition c > 0 is an adequate condition for a non-self-correcting system, and the probability that the majority's choice remains wrong in the limit t ->infinity is positive. We apply the method to data from two experiments in which T subjects answered two-choice questions: (i) general knowledge questions (T-avg = 60) and (ii) urn-choice questions (T = 63). We find c > 0 for difficult questions in (i) and all cases in (ii), and the systems are not self-correcting.
• Quantum decision-making in newcomb’s problem: Effect of reward size

  Nobuye Ishibashi-Ohmura, Taiki Takahashi

  NeuroQuantology 13 (3) 293 - 298 1303-5150 2015/09/01 [Refereed][Not invited]
   

  This study experimentally examined people’s decision making in the Newcomb’s problem. We observed that Savage’s sure-thing principle and Kolmogorovian law of probability was violated. Also, the degree of the violation increased as the reward size increased. By adopting quantum decision theory, we further quantified interference effect as a quantum phase factor. The quantum phase also depended on the reward size i.e., it increased as the reward size in the unknown box in the Newcomb’s problem increased. Future directions in the application of the present theory to studies in quantum decision theory and neuroeconomics are discussed.
• Reinforcement learning in depression: A review of computational research.

  Chong Chen, Taiki Takahashi, Shin Nakagawa, Takeshi Inoue, Ichiro Kusumi

  Neuroscience and biobehavioral reviews 55 (55) 247 - 67 2015/08 [Refereed][Not invited]
   

  Despite being considered primarily a mood disorder, major depressive disorder (MDD) is characterized by cognitive and decision making deficits. Recent research has employed computational models of reinforcement learning (RL) to address these deficits. The computational approach has the advantage in making explicit predictions about learning and behavior, specifying the process parameters of RL, differentiating between model-free and model-based RL, and the computational model-based functional magnetic resonance imaging and electroencephalography. With these merits there has been an emerging field of computational psychiatry and here we review specific studies that focused on MDD. Considerable evidence suggests that MDD is associated with impaired brain signals of reward prediction error and expected value ('wanting'), decreased reward sensitivity ('liking') and/or learning (be it model-free or model-based), etc., although the causality remains unclear. These parameters may serve as valuable intermediate phenotypes of MDD, linking general clinical symptoms to underlying molecular dysfunctions. We believe future computational research at clinical, systems, and cellular/molecular/genetic levels will propel us toward a better understanding of the disease.
• Activity in the left auditory cortex is associated with individual impulsivity in time discounting.

  Ruokang Han, Taiki Takahashi, Akane Miyazaki, Tomoka Kadoya, Shinya Kato, Koichi Yokosawa

  Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference 2015 6646 - 9 1557-170X 2015 [Refereed][Not invited]
   

  Impulsivity dictates individual decision-making behavior. Therefore, it can reflect consumption behavior and risk of addiction and thus underlies social activities as well. Neuroscience has been applied to explain social activities; however, the brain function controlling impulsivity has remained unclear. It is known that impulsivity is related to individual time perception, i.e., a person who perceives a certain physical time as being longer is impulsive. Here we show that activity of the left auditory cortex is related to individual impulsivity. Individual impulsivity was evaluated by a self-answered questionnaire in twelve healthy right-handed adults, and activities of the auditory cortices of bilateral hemispheres when listening to continuous tones were recorded by magnetoencephalography. Sustained activity of the left auditory cortex was significantly correlated to impulsivity, that is, larger sustained activity indicated stronger impulsivity. The results suggest that the left auditory cortex represent time perception, probably because the area is involved in speech perception, and that it represents impulsivity indirectly.
• Remembrance of happy things past: positive autobiographical memories are intrinsically rewarding and valuable, but not in depression.

  Chong Chen, Taiki Takahashi, Si Yang

  Frontiers in psychology 6 222 - 222 1664-1078 2015 [Refereed][Not invited]
  
• The Q-Exponential Decay of Subjective Probability for Future Reward: A Psychophysical Time Approach

  Taiki Takahashi, Shinsuke Tokuda, Masato Nishimura, Ryo Kimura

  ENTROPY 16 (10) 5537 - 5545 1099-4300 2014/10 [Refereed][Invited]
   

  This study experimentally examined why subjective probability for delayed reward decays non-exponentially ("hyperbolically", i.e., q < 1 in the q-exponential discount function) in humans. Our results indicate that nonlinear psychophysical time causes hyperbolic time-decay of subjective probability for delayed reward. Implications for econophysics and neuroeconomics are discussed.
• 脳科学と組織科学の接面を求めて ニューロエコノミックスの新展開―心理物理学的神経経済学―

  高橋泰城

  組織科学 白桃書房 47 (4) 23 - 34 0286-9713 2014/06 [Refereed][Invited]
  
• Toward a physical theory of quantum cognition.

  Taiki Takahashi

  Topics in cognitive science 6 (1) 104 - 7 2014/01 [Refereed][Not invited]
   

  Recently, mathematical models based on quantum formalism have been developed in cognitive science. The target articles in this special issue of Topics in Cognitive Science clearly illustrate how quantum theoretical formalism can account for various aspects of human judgment and decision making in a quantitatively and mathematically rigorous manner. In this commentary, we show how future studies in quantum cognition and decision making should be developed to establish theoretical foundations based on physical theory, by introducing Taketani's three-stage theory of the development of science. Also, implications for neuroeconomics (another rapidly evolving approach to human judgment and decision making) are discussed.
• Neuroeconomics of psychopathy: risk taking in probability discounting of gain and loss predicts psychopathy.

  Taiki Takahashi, Haruto Takagishi, Hirofumi Nishinaka, Takaki Makino, Hiroki Fukui

  Neuro endocrinology letters 35 (6) 510 - 7 0172-780X 2014 [Refereed][Not invited]
   

  BACKGROUND: This study investigated the relationships between psychopathy and impulsive and risky decision making, by utilizing intertemporal and probabilistic choices for both gain and loss, in addition to the Iowa gambling task. METHODS: The Psychopathic Personality Inventory-Revised - a 154-item measure that assesses psychopathic traits by self-report - was used with a 4-point response scale to assess 113 undergraduate students from three Japanese universities. Participants' performance on the Iowa Gambling Task and four behavioral neuroeconomic tasks of discounting - delayed gain, delayed loss, uncertain gain, and uncertain loss - were estimated. RESULTS: Risky decisions in probability discounting of gain and loss were associated with psychopathy. Psychopathic traits had no relationship with performance on the Iowa Gambling and were not significantly related to delay discounting. CONCLUSIONS: Psychopathy is predicted by risky decision in probability discounting of gain and loss, but not strongly associated with future myopia. Implications of the present findings for neuroeconomics and neurolaw are discussed.
• Collective adoption of max-min strategy in an information cascade voting experiment

  Shintaro Mori, Masato Hisakado, Taiki Takahashi

  Journal of the Physical Society of Japan 82 (8) 0031-9015 2013/08 [Refereed][Not invited]
   

  We consider a situation where one has to choose an option with multiplier m. The multiplier is inversely proportional to the number of people who have chosen the option and is proportional to the return if it is correct. If one does not know the correct option, we call him a herder, and then there is a zero-sum game between the herder and other people who have set the multiplier. The max-min strategy where one divides one's choice inversely proportional to m is optimal from the viewpoint of the maximization of expected return. We call the optimal herder an analog herder. The system of analog herders takes the probability of correct choice to one for any value of the ratio of herders, p < 1, in the thermodynamic limit if the accuracy of the choice of informed person q is one. We study how herders choose by a voting experiment in which 50 to 60 subjects sequentially answer a two-choice quiz. We show that the probability of selecting a choice by the herders is inversely proportional to m for 4=3 ≤ m ≤ 4 and they collectively adopt the max-min strategy in that range. © 2013 The Physical Society of Japan.
• Smokers, smoking deprivation, and time discounting

  Shoko Yamane, Hiroyasu Yoneda, Taiki Takahashi, Yoshio Kamijo, Yasuhiro Komori, Fumihiko Hiruma, Yoshiro Tsutsui

  Journal of Socio-Economics 45 47 - 56 1053-5357 2013/08 [Refereed][Not invited]
   

  This paper investigates whether smokers exhibit greater time discounting than non-smokers, and how short-term nicotine deprivation affects time discounting. A unique feature of our experiment is that our subjects receive rewards not only of money, but also of actual tobacco. This is done in order to elicit smokers' true preferences. Smokers are more impatient than non-smokers, consistent with previous studies. Additionally, nicotine deprivation makes smokers even more impatient. These results suggest that nicotine concentration has different effects on time preferences in the short and long runs. © 2013 Elsevier Inc.
• DNA polymorphism in the FKBP5 gene affects impulsivity in intertemporal choice.

  Yoshiya Kawamura, Taiki Takahashi, Xiaoxi Liu, Nao Nishida, Katsushi Tokunaga, Ko Ukawa, Yoshihiro Noda, Akane Yoshikawa, Takafumi Shimada, Tadashi Umekage, Tsukasa Sasak

  Asia-Pacific psychiatry : official journal of the Pacific Rim College of Psychiatrists 5 (1) 31 - 8 1758-5864 2013/03 [Refereed][Not invited]
   

  INTRODUCTION: Impulsivity in intertemporal choice has been operationalized as "delay discounting", referring to the preference for a sooner, smaller reward. FK506 binding protein 5 (FKBP5) is a co-chaperone of the glucocorticoid receptor (GR). FKBP5 overexpression causes GR resistance, resulting in increased plasma cortisol levels. High cortisol levels are associated with low impulsivity in intertemporal choice. The aim of this study was to explore the effect of single nucleotide polymorphisms (SNPs) in FKBP5 on delay discounting. METHODS: The participants consisted of 91 healthy Japanese people (66 males and 25 females with a mean age of 40.9 ± 6.9 years). Each participant completed Kirby's monetary choice questionnaire (MCQ) and donated a whole blood sample. Five SNPs in FKBP5 were genotyped using the DigiTag2. SNP linear regression analyses with 100,000 permutations were conducted for the hyperbolic time-discount rate (k). RESULTS: Two SNPs were excluded from analysis because of their low minor allelic frequencies. The SNP rs1360780 showed a significant association; participants with more minor alleles (T) were less impulsive in intertemporal choice for delayed gain (multiplicity-corrected P = 0.047). DISCUSSION: The significant SNP rs1360780 is located in the region adjacent to the hormone response element (HRE)-binding sequence where transcription factors bind and alter the transcription of FKBP5. A minor allele (T) of rs1360780, which causes FKBP5 overexpression, may reduce impulsivity in intertemporal choice (i.e. delay discounting) via GR resistance and the subsequent high cortisol levels. This is the first study to demonstrate an association between FKBP5 and impulsivity in intertemporal choice.
• A psychophysical theory of Shannon entropy.

  Taiki Takahashi

  Neuro endocrinology letters 34 (7) 615 - 7 0172-780X 2013 [Refereed][Not invited]
   

  Connections between information theory and decision under uncertainty have been attracting attention in econophysics, neuroeconomics and quantum decision theory. This paper proposes a psychophysical theory of Shannon entropy based on a mathematical equivalence of delay and uncertainty in decision-making, and psychophysics of the perception of waiting time in probabilistic choices. Furthermore, it is shown that the well-known Shannon entropy is a special case of the general psychophysical entropy. Future directions in the application of the present theory to studies in econophysics and neuroeconomics are discussed.
• Psychophysical neuroeconomics of decision making: Nonlinear time perception commonly explains anomalies in temporal and probability discounting

  Taiki Takahashi, Ruokang Han

  Applied Mathematics 4 (11) 1520 - 1525 1005-1031 2013 [Refereed][Not invited]
   

  Anomalies in decision over time (e.g., “hyperbolic time discounting”) and under risk (e.g., Allais paradox and hyperbolic probability discounting) have been attracting attention in behavioral and neuroeconomics. We have proposed that psychophysical time commonly explains anomalies in both decisions (Takahashi, 2011, Physica A Takahashi et al, 2012, J Behav Econ & Finance). By adopting the q-exponential time and probability discounting models, our psycho-physical and behavioral economic experiment confirmed that nonlinear distortion of psychophysical time is a common cause of the anomalies in decision both over time and under risk (i.e., intertemporal choice and decision under risk). Implications for psychophysical neuroeconomics and econophysics are discussed.
• Mathematical neurolaw of crime and punishment: The q-exponential punishment function.

  Yokoyama T, Takahashi T

  Applied Mathematics 2013 [Refereed][Not invited]
  
• Towards a physical theory of quantum decision making.

  Taiki Takahashi

  Topics in Cognitive Science 2013 [Refereed][Invited]
  
• The q-Exponential Probability Discounting of Gain and Loss

  T Takahashi, R Han, H Nishinaka, T Makino, H Fukui

  Applied Mathematics 4, 876-881 2013 [Refereed][Not invited]
  
• The q-Exponential Social Discounting Functions of Gain and Loss

  T Takahashi

  Applied Mathematics 4, 445-448 2013 [Refereed][Not invited]
  
• Socio-Emotional Status, Education, and Time-Discounting in Japanese Non-Smoking Population: A Multi-Generational Study

  Shoko Yamane, Taiki Takahashi, Akiko Kamesaka, Yoshiro Tsutsui, Fumio Ohtake

  Psychology 4 (2) 124-132 - 124-132 2013 [Refereed][Not invited]
  
• Variation in the DRD2 gene affects impulsivity in intertemporal choice

  Yoshiya Kawamura, Taiki Takahashi, Xiaoxi Liu, Nao Nishida, Yoshihiro Noda, Akane Yoshikawa, Tadashi Umekage, Tsukasa Sasaki

  Open Journal of Psychiatry, 2013, 3, 26-31 2013 [Refereed][Not invited]
  
• rationality in quantum decision theory

  Takahashi Taiki

  科学哲学 日本科学哲学会 ; 1968- 46 (2) 17 - 30 0289-3428 2013 [Refereed][Invited]
  
• Psychophysics of time perception and valuation in temporal discounting of gain and loss

  Ruokang Han, Taiki Takahashi

  PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIONS 391 (24) 6568 - 6576 0378-4371 2012/12 [Refereed][Not invited]
   

  Anomalies in intertemporal choice (e.g. "hyperbolic" discounting and sign effect) have been investigated in econophysics and behavioral neuroeconomics. We experimentally examined the roles of psychophysical effects of time perception and subjective valuation of outcomes (value function) on temporal discounting of gain and loss, by utilizing a q-exponential temporal discounting model developed in Tsallis's thermostatistics. Consequently, we demonstrated that both "hyperbolic" discounting and the sign effect (i.e. gain is more steeply time-discounted than loss) are due to psychophysical effects of time perception (i.e., nonlinearity and gain-loss asymmetry). Implications of the present study for neuroeconomics and econophysics are discussed. (C) 2012 Elsevier B.V. All rights reserved.
• An Experimental Comparison of Quantum Decision Theoretical Models of Intertemporal Choice for Gain and Loss

  T Takahashi, H Nishinaka, T Makino, R Han, H Fukui

  Journal of Quantum Information Science 2 119-122  2012/12 [Refereed][Not invited]
  
• Emotion Interference Solves Social Dilemma

  Taiki Takahashi

  Theoretical Economics Letters 2, 446-449 2012/12 [Refereed][Not invited]
  
• A nonlinear neural population coding theory of quantum cognition and decision making

  Takahashi Taiki, Taksu Cheon

  A nonlinear neural population coding theory of quantum cognition and decision making 2, 183 - -186 2012/12 [Refereed][Not invited]
  
• Quantum Phenomenology of Conjunction Fallacy

  Taksu Cheon, Taiki Takahashi

  JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN 81 (10) 0031-9015 2012/10 [Refereed][Not invited]
   

  A quantum-like description of human decision process is developed, and a heuristic argument supporting the theory as sound phenomenology is given. It is shown to be capable of quantitatively explaining the conjunction fallacy in the same footing as the violation of sure-thing principle.
• DNA polymorphism in the FKBP5 gene affects impulsivity in intertemporal choice

  Yoshiya Kawamura, Taiki Takahashi, Xiaoxi Liu, Nao Nishida, Katsushi Tokunaga, Tadashi Umekage, Tsukasa Sasaki

  ASIA-PACIFIC PSYCHIATRY 4 147 - 147 1758-5864 2012/10 [Refereed]
  
• Phase transition to a two-peak phase in an information-cascade voting experiment.

  Shintaro Mori, Masato Hisakado, Taiki Takahashi

  Physical review. E, Statistical, nonlinear, and soft matter physics 86 (2 Pt 2) 026109 - 026109 1539-3755 2012/08 [Refereed][Not invited]
   

  Observational learning is an important information aggregation mechanism. However, it occasionally leads to a state in which an entire population chooses a suboptimal option. When this occurs and whether it is a phase transition remain unanswered. To address these questions we perform a voting experiment in which subjects answer a two-choice quiz sequentially with and without information about the prior subjects' choices. The subjects who could copy others are called herders. We obtain a microscopic rule regarding how herders copy others. Varying the ratio of herders leads to qualitative changes in the macroscopic behavior of about 50 subjects in the experiment. If the ratio is small, the sequence of choices rapidly converges to the correct one. As the ratio approaches 100%, convergence becomes extremely slow and information aggregation almost terminates. A simulation study of a stochastic model for 10(6) subjects based on the herder's microscopic rule shows a phase transition to the two-peak phase, where the convergence completely terminates as the ratio exceeds some critical value.
• Time Discounting: Psychophysics of Intertemporal and Probabilistic Choices

  T Takahashi, R Han, F Nakamura

  Journal of Behavioral Economics and Finance 行動経済学会 5 10-14 - 14 2185-3568 2012/08 [Refereed][Invited]
   

  Intertemporal and probabilistic choices have been attracting attention in behavioral neuroeconomics. Although recent advances in neuroeconomics demonstrated neural processes underlying intertemporal and probabilistic choices, the roles of psychophysical effects on the choices have largely been understudied. In this paper, we review the roles of psychophysical effects in time and risk attitudes. It is shown that Loewenstein-Prelec's generalized hyperbolic temporal discount function (Loewenstein and Prelec (1992)) and Prelec's probability weighting function (Prelec (1998)) are naturally derived from psychophysical laws of time-perception.
• Tempospect Theory of Intertemporal Choice

  Takahashi Taiki

  Psychology 3 ((8)) 555-557 - 555-557 2012/08 [Refereed][Not invited]
  
• Molecular neuroeconomics of crime and punishment: implications for neurolaw.

  Taiki Takahashi

  Neuro endocrinology letters 33 (7) 667 - 73 0172-780X 2012 [Refereed][Not invited]
   

  Criminal behaviors have been associated with risk, time and social preferences in economics (Becker 1968; Davis 1988), criminology (Chamlin & Cochran 1997), and neurolaw (Goodenough & Tucker 2010). This study proposes a molecular neuroeconomic framework for the investigation into crime and punishment. Neuroeconomic parameters (e.g., risk-attitude, probability weighting, time discounting in intertemporal choice, loss aversion, and social discounting) are predicted to be related to criminal behavior. Neurobiological and neuroendocrinological substrates such as serotonin, dopamine, norepinephrine, cortisol (a stress hormone), sex hormones (e.g., testosterone), and oxytocin in brain regions such as the orbitofrontal cortex, the amygdala, and the cingulate may be related to the neuroeconomic parameters governing criminal behaviors. The present framework may help us develop "neurolaw" based on molecular neuroeconomics of criminal and antisocial decision-making processes.
• Quantum Decision Theory for Computational Psychiatry

  Taiki Takahashi

  NEUROQUANTOLOGY 10 (4) 688 - 691 1303-5150 2012 [Refereed][Not invited]
   

  Quantum probabilistic models (based on quantum decision theory) have recently been introduced into cognitive and behavioral sciences. However, to date, quantum decision theory has not been utilized in computational psychiatry, although mathematical models from neuroeconomics have already prevailed in neuropsychiatric research. We address, in the present paper, the importance of employing quantum decision theory in psychiatry. As an example, a possible application of quantum decision theory to autism research is focused. Future study directions in computational psychiatry employing quantum decision theory are discussed.
• Depressive patients are more impulsive and inconsistent in intertemporal choice behavior for monetary gain and loss than healthy subjects- an analysis based on Tsallis' statistics

  Taiki Takahashi, Hidemi Oono, Takeshi Inoue, Shuken Boku, Yuki Kako, Yuji Kitaichi, Ichiro Kusumi, Takuya Masui, Shin Nakagawa, Katsuji Suzuki, Teruaki Tanaka, Tsukasa Koyama, Mark H, B. Radford

  Neuro Endocrinol Lett. 2008, 29(3):351-358 2011/11 [Refereed][Not invited]
   

  Depression has been associated with impaired neural processing of reward and
  punishment. However, to date, little is known regarding the relationship
  between depression and intertemporal choice for gain and loss. We compared
  impulsivity and inconsistency in intertemporal choice for monetary gain and
  loss (quantified with parameters in the q-exponential discount function based
  on Tsallis' statistics) between depressive patients and healthy control
  subjects. This examination is potentially important for advances in
  neuroeconomics of intertemporal choice, because depression is associated with
  ...
• Psychophysics of the probability weighting function

  Taiki Takahashi

  PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIONS 390 (5) 902 - 905 0378-4371 2011/03 [Refereed][Not invited]
   

  A probability weighting function w(p) for an objective probability p in decision under risk plays a pivotal role in Kahneman-Tversky prospect theory. Although recent studies in econophysics and neuroeconomics widely utilized probability weighting functions, psychophysical foundations of the probability weighting functions have been unknown. Notably, a behavioral economist Prelec (1998) [4] axiomatically derived the probability weighting function w (p) = exp(-(-In p)(alpha)) (0 < alpha < 1 and w (0) = 1, -w = (1/e) = (1/e), w (1) = 1), which has extensively been studied in behavioral neuroeconomics. The present study utilizes psychophysical theory to derive Prelec's probability weighting function from psychophysical laws of perceived waiting time in probabilistic choices. Also, the relations between the parameters in the probability weighting function and the probability discounting function in behavioral psychology are derived. Future directions in the application of the psychophysical theory of the probability weighting function in econophysics and neuroeconomics are discussed. (C) 2010 Elsevier B.V. All rights reserved.
• A neuroeconomic theory of rational addiction and nonlinear time-perception

  Taiki Takahashi

  NEUROENDOCRINOLOGY LETTERS 32 (3) 221 - 225 0172-780X 2011 [Refereed][Not invited]
   

  Neuroeconomic conditions for "rational addiction" (Becker & Murphy 1988) have been unknown. This paper derived the conditions for "rational addiction" by utilizing a nonlinear time-perception theory of "hyperbolic" discounting, which is mathematically equivalent to the q-exponential intertemporal choice model based on Tsallis' statistics. It is shown that (i) Arrow-Pratt measure for temporal cognition corresponds to the degree of irrationality (i.e., Prelec's "decreasing impatience" parameter of temporal discounting) and (ii) rationality in addicts is controlled by a nondimensionalization parameter of the logarithmic time-perception function. Furthermore, the present theory illustrates the possibility that addictive drugs increase impulsivity via dopaminergic neuroadaptation without increasing irrationality. Future directions in the application of the model to studies in neuroeconomics are discussed.
• Neuroeconomics of suicide

  NeuroEndocrinology Letters 32 (4) 400 - 404 2011 [Refereed][Not invited]
  
• Interference and inequality in quantum decision theory

  Taksu Cheon, Taiki Takahashi

  PHYSICS LETTERS A 375 (2) 100 - 104 0375-9601 2010/12 [Refereed][Not invited]
   

  The quantum decision theory is examined in its simplest form of two-condition two-choice setting. A set of inequalities to be satisfied by any quantum conditional probability describing the decision process is derived. Experimental data indicating the breakdown of classical explanations are critically examined with quantum theory using the full set of quantum phases. (C) 2010 Elsevier B.V. All rights reserved.
• Toward molecular neuroeconomics of obesity

  Taiki Takahashi

  MEDICAL HYPOTHESES 75 (4) 393 - 396 0306-9877 2010/10 [Refereed][Not invited]
   

  Because obesity is a risk factor for many serious illnesses such as diabetes, better understandings of obesity and eating disorders have been attracting attention in neurobiology, psychiatry, and neuroeconomics. This paper presents future study directions by unifying (i) economic theory of addiction and obesity [4-6], and (ii) recent empirical findings in neuroeconomics and neurobiology of obesity and addiction. It is suggested that neurobiological substrates such as adiponectin, dopamine (D2 receptors), endocannabinoids, ghrelin, leptin, nesfatin-1, norepinephrine, orexin, oxytocin, serotonin, vasopressin, CCK, GLP-1, MCH, PYY, and stress hormones (e.g., CRF) in the brain (e.g., OFC, VTA, NAcc, and the hypothalamus) may determine parameters in the economic theory of obesity. Also, the importance of introducing time-inconsistent and gain/loss-asymmetrical temporal discounting (intertemporal choice) models based on Tsallis' statistics and incorporating time-perception parameters into the neuroeconomic theory is emphasized. Future directions in the application of the theory to studies in neuroeconomics and neuropsychiatry of obesity at the molecular level, which may help medical/psychopharmacological treatments of obesity (e.g., with sibutramine), are discussed. (C) 2010 Elsevier Ltd. All rights reserved.
• A neuroeconomic theory of bidirectional synaptic plasticity and addiction

  Taiki Takahashi

  MEDICAL HYPOTHESES 75 (4) 356 - 358 0306-9877 2010/10 [Refereed][Not invited]
   

  Neuronal mechanisms underlying addiction have been attracting attention in neurobiology, economics, neuropsychiatry, and neuroeconomics. This paper proposes a possible link between economic theory of addiction [2] and neurobiological theory of bidirectional synaptic plasticity [5] based on recent findings in neuroeconomics and neurobiology of addiction. Furthermore, it is suggested that several neurobiological substrates such as cortisol (a stress hormone), NMDA and AMPA receptors/subunits and intracellular calcium in the postsynaptic neurons are critical factors determining parameters in Becker and Murphy's economic theory of addiction. Future directions in the application of the theory to studies in neuroeconomics and neuropsychiatry of addiction and its relation to stress at the molecular level are discussed. (C) 2010 Elsevier Ltd. All rights reserved.
• A social discounting model based on Tsallis' statistics

  Taiki Takahashi

  PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIONS 389 (17) 3600 - 3603 0378-4371 2010/09 [Refereed][Not invited]
   

  Social decision making (e.g. social discounting and social preferences) has been attracting attention in economics, econophysics, social physics, behavioral psychology, and neuroeconomics. This paper proposes a novel social discounting model based on the deformed algebra developed in the Tsallis' non-extensive thermostatistics. Furthermore, it is suggested that this model can be utilized to quantify the degree of consistency in social discounting in humans and analyze the relationships between behavioral tendencies in social discounting and other-regarding economic decision making under game-theoretic conditions. Future directions in the application of the model to studies in econophysics, neuroeconomics, and social physics, as well as real-world problems such as the supply of live organ donations, are discussed. (C) 2010 Elsevier B.V. All rights reserved.
• Salivary alpha-amylase levels and big five personality factors in adults

  Keigo Inukai, Mizuho Shinada, Shigehito Tanida, Chisato Takahashi, Nobuhiro Mifune, Haruto Takagishi, Yutaka Horita, Hirofumi Hashimoto, Kunihiro Yokota, Tatsuya Kameda, Toshio Yamagishi, Taiki Takahashi

  NEUROENDOCRINOLOGY LETTERS 31 (6) 771 - 774 0172-780X 2010 [Refereed][Not invited]
   

  OBJECTIVES: Salivary alpha-amylase (sAA) has been utilized as a non-invasive measure of sympathoadrenal medullary (SAM) activation. Little is known regarding the relationship between personality inventories and baseline sAA. This study was designed to examine the relationships between the scores of big five inventory (BFI) factors, age, and sAA in adults (aged twenty to seventy years old). METHODS: We assessed 97 participants' BFI scores and sAA. The correlations between the BFI factor scores and sAA were examined. RESULTS: We observed (1) a positive correlation between Neuroticism and sAA, and a negative correlation between Agreeableness and sAA and (2) a positive correlation between age and sAA. These correlations between BFI scores and sAA remained significant after controlling for age. After controlling for age, all BFI factors except Conscientiousness were related to sAA. CONCLUSIONS: Subjects with high Neuroticism and low Extraversion, Agreeableness and Openness may have high sAA. sAA has been demonstrated to be useful for examining the relationship between adrenergic activity and personality, in a non-invasive manner.
• Salivary testosterone levels and autism-spectrum quotient in adults

  Haruto Takagishi, Taiki Takahashi, Toshio Yamagishi, Mizuho Shinada, Keigo Inukai, Shigehito Tanida, Nobuhiro Mifune, Yutaka Horita, Hirofumi Hashimoto, Li Yang, Tatsuya Kameda

  NEUROENDOCRINOLOGY LETTERS 31 (6) 837 - 841 0172-780X 2010 [Refereed][Not invited]
   

  OBJECTIVES: The purpose of this study is to examine the relationship between salivary testosterone levels and autistic traits in adults. METHODS: A total of 92 male and female adults participated in the present study. Their salivary testosterone level (T) and score of Japanese version of Autism-spectrum Quotient (AQ) were assessed to examine the relationship between salivary testosterone level and autistic traits in adults. RESULTS: We observed a positive correlation between T and AQ in a group of both sexes. The correlation disappeared when we conducted correlation analysis by sex. However, although there was no sex difference in the score of the subscale of attention switching, attention switching was related to T. CONCLUSIONS: Although the relationship between T and AQ may mainly result from sex differences, the subscale of attention switching may be modulated by testosterone.
• Stress hormones predict hyperbolic time-discount rates six months later in adults

  Taiki Takahashi, Mizuho Shinada, Keigo Inukai, Shigehito Tanida, Chisato Takahashi, Nobuhiro Mifune, Haruto Takagishi, Yutaka Horita, Hirofumi Hashimoto, Kunihiro Yokota, Tatsuya Kameda, Toshio Yamagishi

  NEUROENDOCRINOLOGY LETTERS 31 (5) 616 - 621 0172-780X 2010 [Refereed][Not invited]
   

  OBJECTIVES: Stress hormones have been associated with temporal discounting. Although time-discount rate is shown to be stable over a long term, no study to date examines whether individual differences in stress hormones could predict individuals' time-discount rates in the relatively distant future (e.g., six month later), which is of interest in neuroeconomics of stress-addiction association. METHODS: We assessed 87 participants' salivary stress hormone (cortisol, cortisone, and alpha-amylase) levels and hyperbolic discounting of delayed rewards consisting of three magnitudes, at the time-interval of six months. For salivary steroid assays, we employed a liquid chromatography/mass spectroscopy (LC/MS) method. The correlations between the stress hormone levels and time-discount rates were examined. RESULTS: We observed that salivary alpha-amylase (sAA) levels were negatively associated with time-discount rates in never-smokers. Notably, salivary levels of stress steroids (i.e., cortisol and cortisone) negatively and positively related to time-discount rates in men and women, respectively, in never-smokers. Ever-smokers' discount rates were not predicted from these stress hormone levels. CONCLUSIONS: Individual differences in stress hormone levels predict impulsivity in temporal discounting in the future. There are sex differences in the effect of stress steroids on temporal discounting; while there was no sex defference in the relationship between sAA and temporal discounting.
• Theoretical Frameworks for Neuroeconomics of Intertemporal Choice

  Taiki Takahashi

  Journal of Neuroscience, Psychology, and Economics 2 (2) 75 - 90 1937-321X 2009/11 [Refereed][Not invited]
   

  Intertemporal choice has drawn attention in behavioral economics, econophysics, and neuroeconomics. In recent studies in mainstream economics, inconsistency in intertemporal choice (dynamic inconsistency) has mainly been focused whereas in behavioral economics of addiction, impulsivity/impatience in intertemporal choice has been extensively studied. Recent advances in neuroeconomic and econophysical studies on intertemporal choice have made it possible to study both impulsivity and inconsistency in intertemporal choice within a unified framework. In this paper, I propose the new frameworks for investigations into neuroeconomics of intertemporal choice. The importance of studying neurochemical and neuroendocrinological modulations of intertemporal choice and time perception (e.g., serotonin, dopamine, cortisol, testosterone, and epinephrine) is emphasized. © 2009 American Psychological Association.
• Tsallis' non-extensive free energy as a subjective value of an uncertain reward

  Taiki Takahashi

  PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIONS 388 (5) 715 - 719 0378-4371 2009/03 [Refereed][Not invited]
   

  Recent studies in neuroeconomics and econophysics revealed the importance of reward expectation in decision under uncertainty. Behavioral neuroeconomic studies have proposed that the unpreclictability and the probability of an uncertain reward are distinctly encoded as entropy and a distorted probability weight, respectively, ill the separate neural systems. However, previous behavioral economic and decision-theoretic models could not quantify reward-seeking and uncertainty aversion in a theoretically consistent manner. in this paper, we have: (i) proposed that generalized Helmholtz free energy in Tsallis' non-extensive thermostatistics can be utilized to quantify a perceived value of all uncertain reward, and (ii) empirically examined the explanatory powers of the models. Future study directions in neuroeconomics and econophysics by Utilizing the Tsallis' free energy model are discussed. (c) 2008 Elsevier B.V. All rights reserved.
• Cultural neuroeconomics of intertemporal choice

  Taiki Takahashi, Tarik Hadzibeganovic, Sergio A. Cannas, Takaki Makino, Hiroki Fukui, Shinobu Kitayama

  NEUROENDOCRINOLOGY LETTERS 30 (2) 185 - 191 0172-780X 2009/02 [Refereed][Not invited]
   

  According to theories of cultural neuroscience, Westerners and Easterners may have distinct styles of cognition (e.g., different allocation of attention). Previous research has shown that Westerners and Easterners tend to utilize analytical and holistic cognitive styles, respectively. On the other hand, little is known regarding the cultural differences in neuroeconomic behavior. For instance, economic decisions may be affected by cultural differences in neurocomputational processing underlying attention; however, this area of neuroeconomics has been largely understudied. In the present paper, we attempt to bridge this gap by considering the links between the theory of cultural neuroscience and neuroeconomic theory of the role of attention in intertemporal choice. We predict that (i) Westerners are more impulsive and inconsistent in intertemporal choice in comparison to Easterners, and (ii) Westerners more steeply discount delayed monetary losses than Easterners. We examine these predictions by utilizing a novel temporal discounting model based on Tsallis' statistics (i.e. a q-exponential model). Our preliminary analysis of temporal discounting of gains and losses by Americans and Japanese confirmed the predictions from the cultural neuroeconomic theory. Future study directions, employing computational modeling via neural networks, are outlined and discussed.
• Relationship between personality scales of impulsiveness and discounting of monetary gains and losses in smokers and never smokers.

  International Journal of Psychology Research in press  2009 [Refereed][Not invited]
  
• DECISION UNDER AMBIGUITY: EFFECTS OF SIGN AND MAGNITUDE

  Keigo Inukai, Taiki Takahashi

  INTERNATIONAL JOURNAL OF NEUROSCIENCE 119 (8) 1170 - 1178 0020-7454 2009 [Refereed][Not invited]
   

  Decision under ambiguity (uncertainty with unknown probabilities) has been attracting attention in behavioral and neuroeconomics. However, recent neuroimaging studies have mainly focused on gain domains while little attention has been paid to the magnitudes of outcomes. In this study, we examined the effects of the sign (i.e., gain and loss) and magnitude of outcomes on ambiguity aversion and the additivity of subjective probabilities in Ellsberg's urn problem. We observed that (i) ambiguity aversion was observed in both signs, and (ii) subadditivity of subjective probability was not observed in negative outcomes.
• Alcohol use and discounting of delayed and probabilistic gain and loss

  Taiki Takahashi, Yu Ohmura, Hidemi Oono, Mark Radford

  NEUROENDOCRINOLOGY LETTERS 30 (6) 749 - 752 0172-780X 2009 [Refereed][Not invited]
   

  OBJECTIVE: Little is known about the relationship between alcohol and discounting of loss, one of procrastinative behaviors. This study examined the relationship between the frequency of alcohol use and discounting delayed and probabilistic gain and loss, which is of interest in neuroeconomics of addiction. METHODS: Thirty-three subjects conducted tasks of delay and probability discounting of gain and loss. Their alcohol use was also assessed. RESULTS: The frequency of alcohol use was significantly correlated with the degree to which delayed monetary losses were discounted. CONCLUSIONS: Frequent use of alcohol may associate with an increased degree of procrastination. Further, the degrees of delay discounting of loss could be a predictor of a frequent alcohol intake.
• Salivary alpha-amylase levels and rejection of unfair offers in the ultimatum game

  Haruto Takagishi, Takayuki Fujii, Shinya Kameshima, Michiko Koizumi, Taiki Takahashi

  NEUROENDOCRINOLOGY LETTERS 30 (5) 643 - 646 0172-780X 2009 [Refereed][Not invited]
   

  OBJECTIVES: This study aimed to examine the role of emotions in rejection of unfair offers in an ultimatum game, which is of interest in neuroeconomics of fairness. METHODS: Thirty-seven participants played a one-shot ultimatum game as responders and decided whether to accept or reject the unfair offers by the proposers. Salivary alpha-amylase (sAA) was assessed before and after the ultimatum game. RESULTS: Forty-four percent of the participants rejected the unfair offers. While sAA levels of the participants who rejected the unfair offers increased between pre- and post-experiment, sAA levels of the participants who accepted the unfair offers remain unchanged. CONCLUSIONS: Emotional stress response was observed when participants rejected the unfair offers. Our results indicated that rejection of the unfair offers is a reflection of emotional arousal associated with adrenergic activations.
• Neural correlates of the rejection of unfair offers in the impunity game

  Haruto Takagishi, Taiki Takahashi, Akira Toyomura, Nina Takashino, Michiko Koizumi, Toshio Yamagishi

  NEUROENDOCRINOLOGY LETTERS 30 (4) 496 - 500 0172-780X 2009 [Refereed][Not invited]
   

  OBJECTIVES: This study examined the roles of the insula and the anterior cingulate activations in the rejection of unfair offers in the impunity game. METHODS: Fifteen participants played the impunity game in ten trials as responders during neuroimaging. RESULTS: About 45% of the unfair offers were rejected by the responders even when responders could not restore a fair outcome, which cannot be accounted for by social preference of inequity aversion. Imaging data showed that the right anterior insula was activated when participants faced and rejected unfair offers. CONCLUSIONS: The insula activation during a rejection of the unfair offers is the reflection of an emotional response, rather than social preference of inequity aversion. The role of emotion in the neuroeconomics of fairness was demonstrated.
• The relationship between impulsiveness and rejection behavior in the ultimatum game

  Haruto Takagishi, Taiki Takahashi, Toshio Yamagishi

  Impulsivity: Causes, Control and Disorders 217 - 225 2009 

  The purpose of this study is to examine the relationship between impulsiveness and behavioral responses in an economic game known as the ultimatum game. Thirty-one participants played the role of the responder in repeated one-shot ultimatum game. Following the ultimatum game, participants filled out the Barratt Impulsive Scale (BIS-11 Patton et al., 1995). Results showed that the higher the participant scored on impulsiveness, the more likely they were to accept highly unfair offers. This result implied that rejection behavior in the ultimatum game is less impulsive than accepting behavior. © 2009 by Nova Science Publishers, Inc. All rights reserved.
• Biophysics of risk aversion based on neurotransmitter receptor theory

  Taiki Takahashi

  NEUROENDOCRINOLOGY LETTERS 29 (4) 399 - 404 0172-780X 2008/08 [Refereed][Not invited]
   

  Decision under risk and uncertainty has been attracting attention in neuroeconomics and neuroendocrinology of decision-making. This paper demonstrated that the neurotransmitter receptor theory-based value (utility) function can account for human and animal risk-taking behavior. The theory predicts that (i) when dopaminergic neuronal response is efficiently coupled to the formation of ligand-receptor complex, subjects are risk-aversive (irrespective of their satisfaction level) and (ii) when the coupling is inefficient, subjects are risk-seeking at low satisfaction levels, consistent with risk-sensitive foraging theory in ecology. It is further suggested that some anomalies in decision under risk are due to inefficiency of the coupling between dopamine receptor activation and neuronal response. Future directions in the application of the model to studies in neuroeconomics of addiction and neuroendocrine modulation of risk-taking behavior are discussed.
• Salivary alpha-amylase levels and temporal discounting for primary reward under a simulated life-threatening condition

  Taiki Takahashi, Koki Ikeda, Toshikazu Hasegawa

  NEUROENDOCRINOLOGY LETTERS 29 (4) 451 - 453 0172-780X 2008/08 [Refereed][Not invited]
   

  OBJECTIVES: This study was aimed to examine the relationships between salivary alpha-amylase (sAA, a non-invasive biological marker of adrenergic activities) levels and hyperbolic discounting for primary reward under simulated life-threatening condition, which is of interest in psychoneuroendocrinology and neuroeconomics of visceral influences on behavior. METHODS: We assessed degrees to which delayed primary reward (i.e., water) was discounted (hyperbolic discount rates) in 31 healthy male students. Participants' sAA were also assessed. RESULTS: We observed a positive correlation between sAA and hyperbolic discounting for primary reward. CONCLUSIONS: The result indicates that threat-induced visceral urge acutely prompts impulsivity in temporal discounting.
• Depressive patients are more impulsive and inconsistent in intertemporal choice behavior for monetary gain and loss than healthy subjects - An analysis based on Tsallis' statistics

  Taiki Takahashi, Hiderni Oono, Takeshi Inoue, Shuken Boku, Yuki Kako, Yuji Kitaichi, Ichiro Kusumi, Takuya Masui, Shidn Nakagawa, Katsuji Suzuki, Teruaki Tanaka, Tsukasa Koyama, Mark H. B. Radford

  NEUROENDOCRINOLOGY LETTERS 29 (3) 351 - 358 0172-780X 2008/06 [Refereed][Not invited]
   

  OBJECTIVES: Depression has been associated with impaired neural processing of reward and punishment. However, to date, little is known regarding the relationship between depression and intertemporal choice (delay discounting) for gain and loss. This examination is potentially important for advances in neuroeconomics of intertemporal choice, because depression is associated with reduced serotonergic activities in the brain. DESIGN AND SETTING: We compared impulsivity and inconsistency in intertemporal choice for monetary gain and loss between depressive patients and healthy control subjects. METHODS: We conducted delay discounting tasks for gain and loss in depressed and healthy control subjects. We then quantified impulsivity and inconsistency in the delay discounting with parameters in the q-exponential discount function based on Tsallis' statistics. RESULTS: We observed that depressive patients were more impulsive and time-inconsistent in intertemporal choice action for gain and loss, in comparison to healthy controls. MAIN FINDINGS: Depressed patients were more irrational in temporal discounting. Conclusions: The usefulness of the q-exponential discount function for assessing the impaired decision-making by depressive patients was demonstrated. Furthermore, biophysical mechanisms underlying the altered intertemporal choice by depressive patients are discussed in relation to impaired serotonergic neural systems.
• Psychophysics of time perception and intertemporal choice models

  Taiki Takahashi, Hidemi Oono, Mark H. B. Radford

  PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIONS 387 (8-9) 2066 - 2074 0378-4371 2008/03 [Refereed][Not invited]
   

  Intertemporal choice and psychophysics of time perception have been attracting attention in econophysics and neuroeconomics. Several models have been proposed for intertemporal choice: exponential discounting, general hyperbolic discounting (exponential discounting with logarithmic time perception of the Weber-Fechner law, a q-exponential discount model based on Tsallis's statistics), simple hyperbolic discounting, and Stevens' power law-exponential discounting (exponential discounting with Stevens' power time perception). In order to examine the fitness of the models for behavioral data, we estimated the parameters and AIC(C) (Akaike Information Criterion with small sample correction) of the intertemporal choice models by assessing the points of subjective equality (indifference points) at seven delays. Our results have shown that the orders of the goodness-of-fit for both group and individual data were [Weber-Fechner discounting (general hyperbola) > Stevens' power law discounting > Simple hyperbolic discounting > Exponential discounting], indicating that human time perception in intertemporal choice may follow the Weber-Fechner law. Indications of the results for neuropsychopharmacological treatments of addiction and biophysical processing underlying temporal discounting and time perception are discussed. (c) 2007 Elsevier B.V. All rights reserved.
• A comparison between Tsallis's statistics-based and generalized quasi-hyperbolic discount models in humans

  Taiki Takahashi

  PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIONS 387 (2-3) 551 - 556 0378-4371 2008/01 [Refereed][Not invited]
   

  Intertemporal choice has drawn attention in econophysics and neuroeconomics. Both impulsivity and inconsistency in intertemporal choice can be parametrized with a Tsallis's statistics-based q-exponential discount model. Although a recent neuroeconomic study has proposed a dual-self discounting model (a generalized quasi-hyperbolic discounting), no study to date has examined the relationship between the q-exponential and quasi-hyperbolic models. We empirically estimated the inconsistency parameter 1-q in the q-exponential discount function and the parameter of an internal conflict between dual selves in intertemporal choice by humans. We observed that (i) the inconsistency parameter in the q-exponential model is positively related to a conflict between selves within a subject and (ii) q-exponential discounting better fits group data, while quasi-hyperbolic discounting better fits individual data. Our results indicate that (i) inconsistent intertemporal decision-makers may experience strong internal conflict during intertemporal choice behavior, and (ii) the q-exponential and the quasi-hyperbolic discount models should respectively be utilized for group and individual data. The usefulness of the q-exponential and the quasi-hyperbolic in studies of addiction and economic behavior is discussed. (C) 2007 Elsevier B.V. All rights reserved.
• Sex hormonal modulation of hyperbolic discount factor in men

  Taiki Takahashi, Kikue Sakaguchi, Mariko Oki, Toshikazu Hasegawa

  Journal of Neuroscience, Psychology, and Economics 1 (1) 7 - 16 1937-321X 2008 [Refereed][Not invited]
   

  Hormones in the brain have many types of visceral influences on social behavior and economic decision-making. Although hormone-associated visceral effects attract attention in neuroeconomics, little is known regarding the relationship between sex hormones and hyperbolic discounting. Furthermore, although the "discount factor" (a parameter indicating patience in intertemporal choice) is economically relevant and has neural correlates, most neuroeconomic studies on intertemporal choice have been focusing on neuromodulation of logged discount rates, which sometimes results in difficulty in interpretation. This study was aimed to examine linear correlations between chronic sex hormone levels and hyperbolic discount factors of gains and losses in healthy male students. Participants' salivary sex hormone (testosterone) levels were also assessed. We observed a positive linear relationship between testosterone levels and hyperbolic discount factor of gains while no linear relationship between testosterone levels and discount factor of losses was observed. The results indicate that (i) chronic elevation in testosterone may be associated with patience (indicated by a discount factor) in intertemporal choice on gains, (ii) testosterone is unrelated to discounting of delayed losses. Implications for sex hormone-related visceral effects on problematic decision-making (e.g. addiction) and possible neuroendocrinological mechanism (e.g. conversion of testosterone into female hormones in the brain) are discussed. © 2008 Association for NeuroPsychoEconomics.
• A probabilistic choice model based on Tsallis' statistics

  Taiki Takahashi

  PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIONS 386 (1) 335 - 338 0378-4371 2007/12 [Refereed][Not invited]
   

  Decision under risk and uncertainty (probabilistic choice) has been attracting attention in econophysics and neuroeconomics. This paper proposes a probabilistic choice model based on a mathematical equivalence of delay and uncertainty in decision-making, and the deformed algebra developed in the Tsallis' non-extensive thermodynamics. Furthermore, it is shown that this model can be utilized to quantify the degree of consistency in probabilistic choice in humans and animals. Future directions in the application of the model to studies in econophysics, neurofinance, neuroeconomics, and social physics are discussed. (c) 2007 Elsevier B.V. All rights reserved.
• A comparison of intertemporal choices for oneself versus someone else based on Tsallis' statistics

  Talki Takahashi

  PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIONS 385 (2) 637 - 644 0378-4371 2007/11 [Refereed][Not invited]
   

  Impulsivity and inconsistency in intertemporal choice (discounting) have drawn attention in econophysics and neuroeconomics. Although it is well established that most people often show irrational discounting (e.g., hyperbolic discounting), little is known regarding whether the irrationality is mitigated or not, when the choice was performed by someone else instead of subject herself. This point is important for economic policy-making. In order to compare consistency and impulsivity in choices for oneself versus someone else, we experimentally estimated the consistency parameter q in Tsallis' statistics- based discount function for oneself and someone else, by assessing the points of subjective equality (indifference points) at 7 delays (I week to 25 years) in humans. We observed that (i) most people are more inconsistent when the outcomes of intertemporal choice are only relevant to someone else (q = -8.89) than when relevant to oneself (q = -2.63), and (ii) impulsivity, distinguished from inconsistency by utilizing the Tsallis statistics-based q-exponential discount function, is also larger in the choice for someone else than for oneself. Our results indicate that (i) leaving decision-making processes with some others may neither reduce impulsivity nor correct inconsistency and (ii) when q-exponential discounting is utilized, the definition range of q-parameter should be extended to q < 0, and smaller (q < 1) and larger (q> 1) values indicate more inconsistent discounting. Together, the usefulness of the q-exponential discounting for analyzing the dynamic consistency of economic policy was demonstrated in the present study. (C) 2007 Elsevier B.V. All rights reserved.
• Social evaluation-induced amylase elevation and economic decision-making in the dictator game in humans

  Taiki Takahashi, Koki Ikeda, Toshikazu Hasegawa

  NEUROENDOCRINOLOGY LETTERS 28 (5) 662 - 665 0172-780X 2007/10 [Refereed][Not invited]
   

  OBJECTIVE: Little is known regarding the relationship between social evaluation-induced neuroendocrine responses and generosity in game-theoretic situations. Previous studies demonstrated that reputation formation plays a pivotal role in prosocial behavior. This study aimed to examine the relationships between a social evaluation-induced salivary alpha-amylase (sAA) response and generosity in the dictator game. The relationship is potentially important in neuroeconomics of altruism and game theory. METHODS: We assessed sAA and allocated money in the dictator game in male students with and without social evaluation. RESULTS Social evaluation-responders allocated significantly more money than controls; while there was no significant correlation between social evaluation-induced sAA elevation and the allocated money. CONCLUSIONS: Social evaluation significantly increases generosity in the dictator game, and individual differences in trait characteristics such as altruism and reward sensitivity may be important determinants of generosity in the dictator game task.
• Economic decision-making in the ultimatum game by smokers

  Taiki Takahashi

  NEUROENDOCRINOLOGY LETTERS 28 (5) 659 - 661 0172-780X 2007/10 [Refereed][Not invited]
   

  OBJECTIVE: No study to date compared degrees of inequity aversion in economic decision-making in the ultimatum game between non-addictive and addictive reinforcers. The comparison is potentially important in neuroeconomics and reinforcement learning theory of addiction. METHODS: We compared the degrees of inequity aversion in the ultimatum game between money and cigarettes in habitual smokers. RESULTS: Smokers avoided inequity in the ultimatum game more dramatically for money than for cigarettes; i.e., there was a "domain effect" in decision-making in the ultimatum game. CONCLUSIONS: Reward-processing neural activities in the brain for non-addictive and addictive reinforcers may be distinct and the insula activation due to cue-induced craving may conflict with unfair offer-induced insula activation. Future studies in neuroeconomics of addiction should employ game-theoretic decision tasks for elucidating reinforcement learning processes in dopaminergic neural circuits.
• A hyperbolic decay of subjective probability of obtaining delayed rewards

  Taiki Takahashi, Koki Ikeda, Toshikazu Hasegawa

  BEHAVIORAL AND BRAIN FUNCTIONS 3 52  1744-9081 2007/09 [Refereed][Not invited]
   

  Background: Hyperbolic discounting of delayed and probabilistic outcomes has drawn attention in psychopharmacology and neuroeconomics. Sozou's evolutionary theory proposed that hyperbolic delay discounting may be totally attributable to aversion to a decrease in subjective probability of obtaining delayed rewards (SP) which follows a hyperbolic decay function. However, to date, no empirical study examined the hypothesis, although this investigation is important for elucidating the roles of impatience, precaution, and uncertainty aversion in delay discounting processes. Methods: In order to (i) determine the functional form of the relation between delay until receipt and SP, and (ii) examine whether delay discounting is attributable to a decrease in SP, we assessed the subjects' SP and their delay and probability discounting. We examined the fitness of hyperbolic and exponential functions to the assessed SP, and relations between the SP, and delay/probability discounting, and subjective-probability discounting for delayed rewards. Results: The results demonstrated (a) SP decayed hyperbolically as delay increases, (b) a decay of SP was associated with delay discounting, and (c) subjective-probability discounting did not significantly correlate with delay discounting. Conclusion: Our results demonstrated (i) hyperbolic decay of SP is related to delay discounting, and (ii) delay discounting is, however, not attributable to precautious foresight in intertemporal choice. Further, a novel parameter of pure time preference is proposed.
• Sex differences in the relationship between cortisol levels and the Empathy and Systemizing Quotients in humans

  Yoshihisa Nakayama, Taiki Takahashi, Akio Wakabayashi, Hidemi Ono, Mark H. B. Radford

  NEUROENDOCRINOLOGY LETTERS 28 (4) 445 - 448 0172-780X 2007/08 [Refereed][Not invited]
   

  OBJECTIVE: Little is known regarding the relationship between cortisol (a stress hormone) levels and psychological cognitive styles. Baron-Cohen proposed two fundamental cognitive styles, which are measured by the Empathy Quotient (EQ) and the Systemizng Quotient (SQ). Previous studies have examined the influences of prenatal testosterone exposure on EQ and SQ scores. This study aimed to examine the relationships between morning cortisol levels and EQ and SQ scores, and the 'brain types' which were determined by two quotients in both sexes. These relationships are potentially important in the developmental psychopathology of autism and neuroeconomics of empathy. METHODS: We assessed morning cortisol levels with LC/MS (liquid chromatography-mass spectrometry) and ESQ in healthy male and female university students. CONCLUSIONS: Results indicate clear sex differences between brain types: i.e. Etype males and S-type females (participants with atypical cognitive styles) have significantly higher cortisol levels than S-type males and E-type females (participants ftl with typical cognitive styles). Implications for the role of sex in social adaptation of autistic patients are discussed.
• Empirical estimation of consistency parameter in intertemporal choice based on Tsallis' statistics

  Taiki Takahashi, Hidemi Oono, Mark H. B. Radford

  PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIONS 381 338 - 342 0378-4371 2007/07 [Refereed][Not invited]
   

  Impulsivity and inconsistency in intertemporal choice have been attracting attention in econophysics and neuroeconomics. Although loss of self-control by substance abusers is strongly related to their inconsistency in intertemporal choice, researchers in neuroeconomics and psychopharmacology have usually studied impulsivity in intertemporal choice using a discount rate (e.g. hyperbolic k), with little effort being expended on parameterizing subject's inconsistency in intertemporal choice. Recent studies using Tsallis' statistics-based econophysics have found a discount function (i.e. q-exponential discount function), which may continuously parameterize a subject's consistency in intertemporal choice. In order to examine the usefulness of the consistency parameter (0 <= q <= 1) in the q-exponential discounting function in behavioral studies, we experimentally estimated the consistency parameter q in Tsallis' statistics-based discounting function by assessing the points of subjective equality (indifference points) at seven delays (1 week-25 years) in humans (N = 24). We observed that most (N = 19) subjects' intertemporal choice was completely inconsistent (q = 0, i.e. hyperbolic discounting), the mean consistency (0 <= q <= 1) was smaller than 0.5, and only one subject had a completely consistent intertemporal choice (q = 1, i.e. exponential discounting). There was no significant correlation between impulsivity and inconsistency parameters. Our results indicate that individual differences in consistency in intertemporal choice can be parameterized by introducing a q-exponential discount function and most people discount delayed rewards hyperbolically, rather than exponentially (i.e. mean q is smaller than 0.5). Further, impulsivity and inconsistency in intertemporal choice can be considered as separate behavioral tendencies. The usefulness of the consistency parameter q in psychopharmacological studies of addictive behavior was demonstrated in the present study. (c) 2007 Elsevier B.V. All rights reserved.
• Comparison of probabilistic choice models in humans

  Taiki Takahashi, Hidemi Oono, Mark Hb Radford

  BEHAVIORAL AND BRAIN FUNCTIONS 3 20  1744-9081 2007/04 [Refereed][Not invited]
   

  Background: Probabilistic choice has been attracting attention in psychopharmacology and neuroeconomics. Several parametric models have been proposed for probabilistic choice; entropy model, Prelec's probability weight function, and hyperbola-like probability discounting functions. Methods: In order to examine ( i) fitness of the probabilistic models to behavioral data, ( ii) relationships between the parameters and psychological processes, e. g., aversion to possible non-gain in each probabilistic choice and aversion to unpredictability, we estimated the parameters and AICc ( Akaike Information Criterion with small sample correction) of the probabilistic choice models by assessing the points of subjective equality at seven probability values ( 95%-5%). We examined both fitness of the models parametrized by utilizing AICc, and the relationships between the model parameters and equation-free parameter of aversion to possible non-gain. Results: Our results have shown that ( i) the goodness of fitness for group data was [ Entropy model>Prelec's function>General hyperbola>Simple hyperbola]; while Prelec's function best fitted individual data, ( ii) aversion to possible non-gain and aversion to unpredictability are distinct psychological processes. Conclusion: Entropy and Prelec models can be utilized in psychopharmacological and neuroeconomic studies of risky decision-making.
• Two-month stabitity of hyperbotic discount rates for delayed monetary gains in abstinent inpatient alcoholics

  Taiki Takahashi, Aizo Furukawa, Tomohiro Miyakawa, Hitoshi Maesato, Susumu Higuchi

  NEUROENDOCRINOLOGY LETTERS 28 (2) 131 - 136 0172-780X 2007/04 [Refereed][Not invited]
   

  OBJECTIVES: Alcohol dependence has been associated with disrupted neuroendocrine systems, impulsivity in intertemporal choice (delay discounting). However, little is known regarding stability of discount rates in alcoholics. This study examined both differential stability (stability of individual differences) and absolute stability (stability of group mean) of hyperbolic discount rates for monetary gains in severe alcoholic inpatients (diagnosed with DSM-IV) over a 2-month period during abstinence. METHODS: We estimated male alcoholics' discount rates for delayed monetary rewards on the basis of their pattern of choices between smaller immediate rewards (1,100-8,000 yen) and larger, delayed rewards (2,500-8,500 yen; at delays from 1 week to 6 months), two times at 2-month time-interval during hospitalized alcohol withdrawal. RESULTS: It was observed that the alcoholics' mean hyperbolic discount rates for gains had both differential and absolute stability over 2 months, although a slight non-significant decrease in the group mean of the discount rates was observed. CONCLUSIONS: The results indicate that abstinent alcoholic's discount rates are stable over a relatively long-term period. The usefulness of assessing discount rates of addicts in psychoneuroendocrinology and neuroeconomics of addiction is discussed.
• Salivary alpha-amylase levels and hyperbolic discounting in male humans

  Taiki Takahashi, Koki Ikeda, Hirokata Fukushima, Toshikazu Hasegawa

  NEUROENDOCRINOLOGY LETTERS 28 (1) 17 - 20 0172-780X 2007/02 [Refereed][Not invited]
   

  OBJECTIVE: Little is known regarding the role of the sympathetic-adrenal-medullary (SAM) system in self-control and impulsivity in intertemporal choice (delay discounting), although the roles of dopaminergic and serotonergic systems have been extensively examined. This study was aimed to examine the relationships between salivary alpha-amylase (sAA, a non-invasive biological marker of adrenergic/SAM activities) levels and hyperbolic discounting, which is of interest in psychoneuroendocrinology and neuroeconomics. METHODS: We assessed degrees to which delayed monetary gains were discounted (hyperbolic discount rates) in healthy male students. Participants' sAA were also assessed. RESULTS: We observed negative relationships between sAA and hyperbolic discounting of small, medium, and large monetary gains. CONCLUSIONS: The results indicate that subjects with low sAA are impulsive in intertemporal choice. Implications for the roles of adrenergic and SAM systems in self-control in intertemporal choice are discussed.
• Non-reciprocal altruism may be attributable to hyperbolicity in social discounting function

  Taiki Takahashi

  MEDICAL HYPOTHESES 68 (1) 184 - 187 0306-9877 2007 [Refereed][Not invited]
   

  Humans show altruism even for chance acquaintances whom they will never meet again (non-reciprocal altruism). With respect to evolutionary and economic perspectives, reciprocal altruism is not actually puzzling, because reciprocal altruism maximizes subjects' benefit/fitness in the tong run; while non-reciprocal (pure) altruism still presents a challenge to evolutionary biology and neuroeconomics. Understanding neuropsychological bases of nonreciprocal altruism/generosity for unrelated people is also important for neuropsychiatry, because several types of impulsive psychiatrics (e.g., social phobia, substance abusers, psychopaths) often have reduced altruism/generosity for other people, which is associated with their problematic/impulsive social behavior. Regarding the relationship between impulsivity and reciprocal altruism, it has been shown that subjects who are impulsive in intertemporal choice (having a large time-discounting rate) have tow degrees of reciprocal altruism, which is in line with economic theories and neuropharmacologically treatable with serotonin/norepinephrine reuptake inhibitors. However, little is known regarding the relationship between non-reciprocal altruism and discounting behavior, and neuropsychological processing underlying the relationship. Recently, Jones and Rachlin reported that generosity for other individuals with different social distances follows a hyperbolic discounting function, which has been employed to describe inconsistent time-discounting. In this study, I propose that non-reciprocal (pure) altruism may be, at least partially, attributable to hyperbolicity of a social discounting function (inconsistency in "interpersonal choice"). Neuropsychological mechanisms underlying interpersonally-inconsistent social discounting and possible implications for neuropsychopharmacological treatments for impulsive psychiatrics' problematic social behavior are discussed. (c) 2006 Elsevier Ltd. All. rights reserved.
• Hyperbolic discounting may be reduced to electrical coupling in dopaminergic neural circuits

  Taiki Takahashi

  MEDICAL HYPOTHESES 69 (1) 195 - 198 0306-9877 2007 [Refereed][Not invited]
   

  Loss of self-control in drug addicts (e.g. cocaine and amphetamine dependent patients) has been associated with hyperbolic discounting of delayed rewards (i.e., inconsistency in intertemporal choice). Neurobiophysical mechan\isms underlying hyperbolic discounting are stilt unknown in spite of recent extensive work in neuroeconomics. Understanding of neuronal mechanisms of hyperbolic discounting is important for establishing neuropharmacological. treatment of addiction. At the cognitive level, previous studies have indicated that psychophysics of time-estimation (i.e., Weber-Fechner law and Steven's power law of time-perception) may explain inconsistency in intertemporal choice. Regarding neuronal substrates of time-estimation, drugs of abuse dramatically change time-estimation, indicating that dopaminergic activities may mediate time-estimation. With respect to neuronal changes induced by drugs of abuse, recent studies have revealed that gap junction proteins (e.g., connexin 36) in dopamine neurons are increased by an self-administration of dopaminergic drugs such as cocaine and amphetamine. However, it has been yet to be examined how the enhanced electrical coupling due to substance administration induces addiction. Furthermore, a recent biophysical modelling study has demonstrated that the effect of the psychophysical laws are potentiated by non-synaptic electrical coupling between neurons via gap junctions. Based on these current findings, we hypothesized that hyperbolic discounting may be reduced to biophysical characteristics of dopamine neural circuits, that is, electrical coupling between time-encoding dopaminergic neurons via gap junctions. The present hypothesis states that drugs of abuse may induce addiction by exacerbating subject's impulsivity (a discount rate) and inconsistency (hyperbolicity) in intertemporal choice partly due to enhanced expression of gap junction proteins in dopaminergic neurons. Possible psychopharmacological treatments of impulsivity in drug addicts implied by our present hypothesis, e.g., administration of a gap junction blocker, are discussed. (C) 2006 Elsevier Ltd. All rights reserved.
• Three-month stability of delay and probability discounting measures

  Yu Ohmura, Taiki Takahashi, Nozomi Kitamura, Paul Wehr

  EXPERIMENTAL AND CLINICAL PSYCHOPHARMACOLOGY 14 (3) 318 - 328 1064-1297 2006/08 [Refereed][Not invited]
   

  Psychopharmacologists are interested in delay and probability discounting because the tendency to discount the value of future and uncertain rewards has been linked with drug dependency. However, relatively little is known about the long-term stability of discounting measures typically studied in clinical psychopharmacology. To evaluate the stability of discounting over a 3-month period, the authors compared points of subjective equality (indifference points) with those collected from the same subjects 3 months earlier. Seven delay periods, ranging from 1 week to 25 years, and 7 probability values, ranging from.95 to .05, were assessed in an undergraduate sample (n = 22, delay discounting; n = 18, probability discounting). The authors examined both differential stability (stability of individual differences) and absolute stability (stability of the group mean) of delay and probability discounting measures as well as their respective indifference points. The results demonstrate that standard delay and probability discounting parameters (e.g., hyperbolic k and area under the curve) had both differential stability and absolute stability across 3 months. Moreover, most indifference points in the delay and probability discounting tasks demonstrated both differential and absolute stability. All together, these results suggest that delay and probability parameters are stable enough to predict future behavior, such as substance abuse. Additional findings indicated that a hyperbolic function fitted the data better than an exponential function and that delay and probability discounting parameters were not significantly correlated.
• Testosterone levels and discounting delayed monetary gains and losses in male humans

  Taiki Takahashi, Kikue Sakaguchi, Mariko Oki, Seijiro Homma, Toshikazu Hasegawa

  NEUROENDOCRINOLOGY LETTERS 27 (4) 439 - 444 0172-780X 2006/08 [Refereed][Not invited]
   

  OBJECTIVES: Although impulsivity has been associated with androgens (e.g., testosterone), little is known regarding the relationship between testosterone levels and impulsivity in intertemporal choice (delay discounting). This study was aimed to examine the relationship between delay discounting of gains and losses and testosterone levels, which is of interest in neuroendocrinology and neuroeconomics. METHODS: We assessed degrees to which delayed monetary gains and losses were discounted (hyperbolic discounting rate) in healty male students (age: 22.4 +/- 2.67). Participants) salivary testosterone levels were also assessed by utilizing liquid chromatography/mass spectroscopy (LC/MS) method. RESULTS: Non-linear curve fitting analysis showed an inverted-U relationship between delay discounting of gains and salivary testosterone levels; while no relationship between salivary testosterone levels and delay discounting of losses was observed. CONCLUSIONS: The results indicate that (i) testosterone may enhance delay discounting rate of gains in non-impulsive subjects, (ii) testosterone may have an opposite (reducing) effect on delay discounting rate of gains in impulsive subjects, and (iii) tcstostcrone is unrelated to subject's sensitivity to future bad outcomes. Implications for evaluating the effects of testosterone treatment and anti-androgenic therapy on impulsive behavior often observed in psychiatrics (e.g., pathological gambling, credit card debt, substance misuse, and needle-sharing) are discussed.
• Distinct neuropsychological processes may mediate decision-making under uncertainty with known and unknown probability in gain and loss frames

  Keigo Inukai, Taiki Takahashi

  Medical Hypotheses 67 (2) 283 - 286 0306-9877 2006 [Refereed][Not invited]
   

  Decision-making under uncertainty has been studied in psychiatry, economic psychology, and neuroeconomics. Psychiatric patients (e.g., drug addicts) often show low degrees of aversion to potential danger. Investigation into neuropsychological processing underlying decision under uncertainty is important for medical treatments of neuropsychiatric disorders. In economic decision theory, choices under uncertainty with and without known probabilities of outcomes have been discriminated. Regarding decision-making under uncertainty with known probabilities (risk), Kahnemann-Tversky's prospect theory revealed that people tend to avoid uncertainty in potential gains (i.e., risk-aversion in a gain-frame) on the contrary, prefer uncertainty in potential losses (i.e., risk-seeking in a loss-frame). Regarding choices between possible gains with known and unknown probabilities, Ellsberg demonstrated that, in a gain-frame, people tend to avoid uncertainty with unknown probabilities, more dramatically than uncertainty with known probabilities. This can be explained by risk/uncertainty aversion in the gain-frame, suggesting that uncertainty with known and unknown probabilities (i.e., risk and Knightian uncertainty, respectively) may possibly be processed by similar neuropsychological processing in the gain-frame. However, in spite of accumulating evidence in neuroimaging and neuroeconomic studies, it is still unknown whether probability and Knightian uncertainty in the loss-frame are mediated by similar neuropsychological processes as well. We propose that distinct neuropsychological processes may mediate potential losses with known and unknown probabilities, based on recent findings in neuroeconomics and our experiment. Importance of examining subjects' degree of Knightian uncertainty aversion for the prediction/treatment of drug addicts' risky behavior (e.g., needle-sharing) is also discussed. © 2006 Elsevier Ltd. All rights reserved.
• A mathematical framework for probabilistic choice based on information theory and psychophysics

  T Takahashi

  MEDICAL HYPOTHESES 67 (1) 183 - 186 0306-9877 2006 [Refereed][Not invited]
   

  Risky decision-making (e.g. reward dependency) has been associated with substance abuse, psychopathy and pathological gambling; conversely, marked sensitivity to risk and uncertainty have been observed in anxiety disorder patients. In economic decision theory, probability and uncertainty have been dissociated. Frank Knight defined uncertainty as loss of information on the probability distribution of outcomes for choices (i.e., unpredictabitity), which is referred to as Knightian uncertainty (also as ambiguity). However, even when the probability distribution of outcomes is known, there are different degrees of predictability. In information theory, this type of degrees of uncertainty/unpredictabitity has been parametrized by introducing Shannon entropy. In the present paper, we show: (i) a mathematical framework combining Shannon entropy in information theory and Weber's law in psychophysics is capable of parametrizing subject's level of both aversion to probabilistic uncertainty (exaggerated in anxiety disorder patients) and reward dependency (enhanced in drug addicts and pathological gamblers), and (ii) this framework has an analogue in thermodynamics, therefore this can readily be utilized in studies in the nascent fields of neuroeconomics and econophysics as well. Future study directions for elucidating maladaptive personality characteristics in neuropsychiatric patients by using the present framework are discussed. (c) 2006 Published by Elsevier Ltd.
• Queuing theory under competitive social foraging may explain a mathematical equivalence of delay and probability in impulsive decision-making

  T Takahashi

  MEDICAL HYPOTHESES 67 (2) 276 - 279 0306-9877 2006 [Refereed][Not invited]
   

  Intertemporal and probabilistic decision-making has been studied in psychiatry, ecology, and neuroeconomics. Because drug addicts and psycopaths often make risky decisions (e.g., drug misuse and aggression), investigation into types of impulsivity in intertemporal and probabilistic choices (delay and probability discounting) are important for psychiatric treatments. Studies in behavioral ecology proposed that delay and probability discounting are mediated by the same psychological process, because a decrease in probability of winning corresponds to an increase in delay until winning. According to this view, odds-against winning (= 1/p-1) in probabilistic choice corresponds to delay in intertemporal choice. This hypothesis predicts that preference of gambling (low degree of probability discounting) may be associated with patience, rather than impulsivity or impatience, in intertemporal choice (low degree of delay discounting). However, recent empirical evidence in psychiatric research employing pathological gamblers indicates that pathological gamblers are impulsive in intertemporal choice (high degrees of delay discounting). However, a hyperbolic discounting function (usually adopted to explain intertemporal choice) with odds-against (instead of delay) explain experimental data in probabilistic choice dramatically well. Therefore, an alternative explanation is required for the hypothetical equivalence of odds-against to delay. We propose that queuing theory (often adopted for analyzing computer network traffic) under a competitive social foraging condition may explain the equivalence. Our hypothesis may help understand impulsivity of psychiatrics in social behavior (e.g., aggression and antisocial behavior) in addition to non-social impulsivity in reward-seeking (e.g., substance misuse). (c) 2006 Elsevier Ltd. All rights reserved.
• Time-estimation error following Weber-Fechner law may explain subadditive time-discounting

  Taiki Takahashi

  MEDICAL HYPOTHESES 67 (6) 1372 - 1374 0306-9877 2006 [Refereed][Not invited]
   

  Impulsivity in drug addicts have been associated with impatience in intertemporal choice, i.e., high degrees to which delayed rewards are discounted, indicating the importance of reducing the degree of discounting in drug addicts. Intertemporal choice (delay discounting) has been attracting attention in neuropsychopharmacology and behavioral neuroeconomics. Recently, behavioral economists have reported that impatience/impulsivity in intertemporal choice is increased if a delay period is presented as a sum of divided time-blocks, which is referred to as subadditive discounting (i.e., "total patience" over the delay period is larger than the "sum of patience" over divided delay periods). This finding implies that abstinent drug addicts may more readily relapse into addiction if an abstinence period is presented as a series of shorter abstinent periods, rather than a single block of a tong abstinence period. Therefore, understanding of neuropsychological processing underlying subadditive discounting is important for establishing medical treatments of drug addiction, although to date, no study has addressed this question. In this study, we propose that time-estimation following Weber-Fechner law, formerly introduced for explaining hyperbolic discounting, may also explain subadditive discounting. Our present hypothesis also predicts that possibility of relapse into drug dependence can be decreased by helping abstinent patients to perceive time-duration of an abstinence/withdrawal period precisely. (c) 2006 Elsevier Ltd. All rights reserved.
• Social memory, social stress, and economic behaviors

  T Takahashi

  BRAIN RESEARCH BULLETIN 67 (5) 398 - 402 0361-9230 2005/11 [Refereed][Not invited]
   

  Social memory plays a pivotal role in social behaviors, from mating behaviors to cooperative behaviors based on reciprocal altruism. More specifically, social/person recognition memory is supposed, by behavioral-economic and game-theoretic analysis, to be required for tit-for-tat like cooperative behaviors to evolve under the N-person iterated prisoner's dilemma game condition. Meanwhile, humans are known to show a social stress response during face-to-face social interactions, which might affect economic behaviors. Furthermore, it is known that there are individual differences in a social stress response, which might be reflected in individual differences in various types of economic behaviors, partially via different capacities of social memory. In the present study, we investigated the acute effects of social stress-induced free cortisol (a stress hormone) elevation on hippocampus-dependent social memory by utilizing the Trier social stress test (consisting of a public speech and a mental arithmetic task). We also examine the correlation between an economic behavior-related personality trait (i.e., general trust scale) and social stress-induced cortisol elevations. We found that (1) social stress acutely impairs social memory during social interaction and (2) interpersonal trust reduces social stress response. Together, interpersonal trust may modulate economic behaviors via stress hormone's action on social cognition-related brain regions. (c) 2005 Elsevier Inc. All rights reserved.
• Discounting delayed and probabilistic monetary gains and losses by smokers of cigarettes

  Y Ohmura, T Takahashi, N Kitamura

  PSYCHOPHARMACOLOGY 182 (4) 508 - 515 0033-3158 2005/11 [Refereed][Not invited]
   

  Rationale: Nicotine dependence has been associated with impulsivity and discounting delayed/uncertain outcomes. Objectives: This study had two main objectives: (1) to examine the relationship between the number of cigarettes consumed per day and the degree to which delayed and uncertain monetary gains and losses are discounted by smokers, and (2) to determine the relationship between the estimated dose of nicotine intake per day and the degree to which four types of discounting occur. Methods: Twenty seven habitual smokers and 23 never smokers participated in this experiment. They were required to choose between immediate and delayed monetary rewards (or losses), or between guaranteed and probabilistic rewards (or losses). Results: The degree to which delayed monetary gains were discounted was significantly and positively correlated with both the number of cigarettes smoked and the estimated dose of nicotine intake per day. Conversely, there was no relationship between smoking and the remaining three types of discounting. Also, mild smokers in our sample did not differ from never smokers in discounting monetary gains or losses. Conclusions: In general, our results suggest that both the frequency of nicotine self-administration, as well as the dosage, are positively associated with greater delay discounting of gains. One neuropsychopharmacological explanation for this effect is that chronic nicotine intake may induce neuroadaptation of the neural circuitry involved in reward processing.
• Cortisol levels and prospective and retrospective memory in humans

  Y Nakayama, T Takahashi, MHB Radford

  NEUROENDOCRINOLOGY LETTERS 26 (5) 599 - 602 0172-780X 2005/10 [Refereed][Not invited]
   

  OBJECTIVES: The aim of this study was to examine (i) the influence of cortisol on both prospective and retrospective memory performance and (ii) the role of emotional valence in both types of memory. METHODS: Thirty-four male students participated in a memory task, which measured both prospective and retrospective memory performance. Baseline salivary cortisol levels were assessed. RESULTS: Spearman s rank order correlation analysis showed a significant positive correlation between salivary cortisol levels and retrospective memory performance for neutral words. Cortisol levels were not significantly correlated with prospective memory performance for either negative nor neutral words. CONCLUSIONS: The present results indicate chronic cortisol levels are positively associated with retrospective memory at relatively low concentration ranges, but not prospective memory, in healthy young men. Implications for evaluating the beneficial effects of low-dose cortisol treatment on posttraumatic stress disorder is discussed.
• Anxiety, reactivity, and social stress-induced cortisol elevation in humans

  T Takahashi, K Ikeda, M Ishikawa, N Kitamura, T Tsukasaki, D Nakama, T Kameda

  NEUROENDOCRINOLOGY LETTERS 26 (4) 351 - 354 0172-780X 2005/08 [Refereed][Not invited]
   

  OBJECTIVES: Traditionally, it has been hypothesized that highly anxious/emotionally reactive subjects may have exaggerated social stress response. We examined the relationship between self-reported anxiety, emotional reactivity, and social stress response. METHODS: We investigated the relationship between personality scales of trait-state anxiety, subjective autonomic reactivity, and salivary cortisol levels before and after social stress exposure (Trier Social Stress Test) in 20 men. RESULTS: Significant positive correlations between anxiety, subjective autonomic reactivity, and basal cortisol levels were observed, while neither anxiety nor subjective autonomic reactivity was correlated with social stress-induced cortisol elevation. CONCLUSIONS: The present results indicate (i) subjects with higher degrees of trait anxiety/subjective autonomic reactivity have higher basal cortisol levels, and (ii) in contrast to the traditional view, anxious personality is not strongly associated with exaggerated cortisol response to social stress.
• Interpersonal trust and social stress-induced cortisol elevation.

  Taiki Takahashi, Koki Ikeda, Miho Ishikawa, Nozomi Kitamura, Takafumi Tsukasaki, Daisuke Nakama, Tatsuya Kameda

  Neuroreport 16 (2) 197 - 9 0959-4965 2005/02/08 [Refereed][Not invited]
   

  A neuroendocrine correlate of interpersonal trust is relatively unknown. We investigated the relationship between an interpersonal trust-related personality (General Trust Scale) and cortisol elevation induced by social stress in 20 men. Spearman's rank order correlation analysis revealed a significant negative correlation between social stress-induced cortisol elevation and General Trust Scale. The present results indicate subjects with higher degrees of interpersonal trust have lower levels of neuroendocrine response to social stress. NeuroReport 16:197-199 (C) 2005 Lippincott Williams Wilkins.
• Loss of self-control in intertemporal choice may be attributable to logarithmic time-perception

  T Takahashi

  MEDICAL HYPOTHESES 65 (4) 691 - 693 0306-9877 2005 [Refereed][Not invited]
   

  Impulsivity and loss of self-control in drug-dependent patients have been associated with the manner in which they discount delayed rewards. Although drugs of abuse have been shown to modify perceived time-duration, little is known regarding the relationship between impulsive decision-making in intertemporat choice and estimation of time-duration. In classical economic theory, it has been hypothesized that people discount future reward value exponentially. In exponential discounting, a temporal discounting rate is constant over time, which has been referred to as dynamic consistency. However, accumulating empirical evidence in biology, psychopharmacology, behavioral neuroscience, and neuroeconomics does not support the hypothesis. Rather, dynamically inconsistent manners of discounting delayed rewards, e.g., hyperbolic discounting, have been repeatedly observed in humans and non-human animals. In spite of recent advances in neuroimaging and neuropsychopharmacological study, the reason why humans and animals discount delayed rewards hyperbolically is unknown. In this study, we hypothesized that empirically-observed dynamical inconsistency in intertemporal choice may result from errors in the perception of time-duration. It is proposed that perception of temporal duration following Weber's law might explain the dynamical inconsistency. Possible future study directions for elucidating neural mechanisms underlying inconsistent intertemporal choice are discussed. (c) 2005 Elsevier Ltd. All rights reserved.
• 1P251 Neuroendocrine modulation of social cognition and economic decision-making

  Takahashi T.

  Seibutsu Butsuri 一般社団法人 日本生物物理学会 45 S94  2005 [Refereed]
  
• Cortisol levels and time-discounting of monetary gain in humans

  T Takahashi

  NEUROREPORT 15 (13) 2145 - 2147 0959-4965 2004/09 [Refereed][Not invited]
   

  This study was conducted to examine the relationship between cortisol levels and preference to a small immediate over a larger delayed monetary reward. The degree of preference to a small immediate reward (a time-discounting rate) was investigated with an economic decision-making task in which each subject made an inter-temporal choice between (a) 10 000 yen available immediately and (b) an equal or larger amount of money after a delay of one year. The time-discounting rate was defined as [the required minimal amount of the delayed monetary gain for (b) to be preferred]-10 000/10 000. Low cortisol levels were shown to associate with a large time-discounting rate, indicating that subjects with low cortisol levels may be impulsive in inter-temporal choice.
• Social stress-induced cortisol elevation acutely impairs social memory in humans

  T Takahashi, K Ikeda, M Ishikawa, T Tsukasaki, D Nakama, S Tanida, T Kameda

  NEUROSCIENCE LETTERS 363 (2) 125 - 130 0304-3940 2004/06 [Refereed][Not invited]
   

  Although stress is known to affect the memory process, little has been elucidated regarding its effect on social memory. In this study, 30 subjects' social memory (face-name association memory) performance was tested. Twenty subjects were exposed to social stress with a subsequent test of social memory, while the remaining ten subjects served as controls. Free cortisol was determined via saliva samples taken before and after the social stress exposure. Because stress hormones might have biphasic actions on neurons, we separated the subjects with cortisol elevations between high and low responders. The high responders had significantly impaired social memory. Furthermore, we observed a negative relation between social stress-induced cortisol elevation and social memory. These results indicate that social stress acutely impairs social memory. (C) 2004 Elsevier Ireland Ltd. All rights reserved.
• ラット脳海馬における環境ホルモンBisphenol-Aの作用の解析

  田辺 伸聡, 高橋 泰城, 服部 高明, 岡田 和嗣, 舩江 良彦, 川戸 佳

  生物物理 (一社)日本生物物理学会 43 (Suppl.1) S232 - S232 0582-4052 2003/08
• Hippocampal cytochrome P450s synthesize brain neurosteroids which are paracrine neuromodulators of synaptic signal transduction.

  Keisuke Shibuya, Norio Takata, Yasushi Hojo, Aizo Furukawa, Nobuaki Yasumatsu, Tetsuya Kimoto, Taihei Enami, Kumiko Suzuki, Nobuaki Tanabe, Hirotaka Ishii, Hideo Mukai, Taiki Takahashi, Taka-aki Hattori, Suguru Kawato

  Biochimica et biophysica acta 1619 (3) 301 - 16 0006-3002 2003/02/17 [Refereed][Not invited]
   

  Hippocampal pyramidal neurons and granule neurons of adult male rats are equipped with a complete machinery for the synthesis of pregnenolone, dehydroepiandrosterone, 17beta-estradiol and testosterone as well as their sulfate esters. These brain neurosteroids are synthesized by cytochrome P450s (P450scc, P45017alpha and P450arom) from endogenous cholesterol. Synthesis is acutely dependent on the Ca(2+) influx attendant upon neuron-neuron communication via N-methyl-D-aspartate (NMDA) receptors. Pregnenolone sulfate, estradiol and corticosterone rapidly modulate neuronal signal transduction and the induction of long-term potentiation via NMDA receptors and putative membrane steroid receptors. Brain neurosteroids are therefore promising neuromodulators that may either activate or inactivate neuron-neuron communication, thereby mediating learning and memory in the hippocampus.
• Hippocampal cytochrome P450s synthesize brain neurosteroids which are paracrine neuromodulators of synaptic signal transduction

  K Shibuya, N Takata, Y Hojo, A Furukawa, N Yasumatsu, T Kimoto, T Enami, K Suzuki, N Tanabe, H Ishii, H Mukai, T Takahashi, T Hattoria, S Kawato

  BIOCHIMICA ET BIOPHYSICA ACTA-GENERAL SUBJECTS 1619 (3) 301 - 316 0304-4165 2003/02 [Refereed][Not invited]
   

  Hippocampal pyramidal neurons and granule neurons of adult male rats are equipped with a complete machinery for the synthesis of pregnenolone, dehydroepiandrosterone, 17beta-estradiol and testosterone as well as their sulfate esters. These brain neurosteroids are synthesized by cytochrome P450s (P450scc, P45017alpha and P450arom) from endogenous cholesterol. Synthesis is acutely dependent on the Ca2+ influx attendant upon neuron-neuron communication via N-methyl-D-aspartate (NMDA) receptors. Pregnenolone sulfate, estradiol and corticosterone rapidly modulate neuronal signal transduction and the induction of long-term potentiation via NMDA receptors and putative membrane steroid receptors. Brain neurosteroids are therefore promising neuromodulators that may either activate or inactivate neuron-neuron communication, thereby mediating learning and memory in the hippocampus. (C) 2002 Elsevier Science B.V. All rights reserved.
• Morphological changes of hippocampal CA1 pyramidal cells caused by 17beta-estradiol

  Tsurugizawa T., Takahashi T., Kawato S.

  Seibutsu Butsuri 一般社団法人 日本生物物理学会 43 S240  2003 [Refereed]
  
• Corticosterone acutely prolonged N-methyl-D-aspartate receptor-mediated Ca2+ elevation in cultured rat hippocampal neurons

  T Takahashi, T Kimoto, N Tanabe, TA Hattori, N Yasumatsu, S Kawato

  JOURNAL OF NEUROCHEMISTRY 83 (6) 1441 - 1451 0022-3042 2002/12 [Refereed][Not invited]
   

  This work reports the first demonstration that corticosterone (CORT) has a rapid and transient effect on NMDA receptor-mediated Ca2+ signaling in cultured rat hippocampal neurons. Using single cell Ca2+ imaging, CORT and agonists of glucocorticoid receptors were observed to modulate the NMDA receptor-mediated Ca2+ signals in a completely different fashion from pregnenolone sulfate. In the absence of steroids, 100 mum NMDA induced a transient Ca2+ signal that lasted for 30-70 s in 86.1% of the neurons prepared from postnatal rats (3-5 days old). After pre-treatment with 0.1-100 mum CORT for 10-20 min, NMDA induced extremely prolonged Ca2+ elevation. This prolonged Ca2+ elevation was terminated by the application of MK-801 and followed by washing out of CORT. The proportion of CORT-modulated neurons within the NMDA-responsive cells increased from 25.1 to 95.5% when the concentration of CORT was raised from 0.1 to 50 mum. Substitution of BSA-conjugated CORT produced essentially the same results. When hippocampal neurons were preincubated with 10 mum cortisol and 1 mum dexamethasone for 20 min, a very prolonged Ca2+ elevation was also observed upon NMDA stimulation. The CORT-prolonged Ca2+ elevation caused a long-lasting depolarization of the mitochondrial membrane, as observed with rhodamine 123. In contrast, incubation with 100 mum pregnenolone sulfate did not considerably alter the time duration of NMDA-induced transient Ca2+ elevation, but caused a significant increase in the peak amplitude of Ca2+ elevation in hippocampal neurons. These results imply that high levels of CORT induce a rapid and non-genomic prolongation of NMDA receptor-mediated Ca2+ elevation, probably via putative membrane surface receptors for CORT in the hippocampal neurons.
• 脳海馬における細胞内シグナル伝達系の,環境ホルモンによるかく乱作用の解析

  田辺 伸聡, 服部 高明, 高橋 泰城, 川戸 佳

  環境ホルモン学会研究発表会要旨集 日本内分泌撹乱物質学会 5回 288 - 288 2002/11
• 1M1030 The endocrine disruptor bisphenol-A evokes intracellular calcium signalling in hippocampal neurons

  Tanabe N., Hattori T., Takahashi T., Kawato S.

  Seibutsu Butsuri 一般社団法人 日本生物物理学会 42 (2) S74  2002 [Refereed]
  
• 海馬における17β・エストラジオール合成とその作用

  服部 高明, 小南 思郎, 北條 泰嗣, 高橋 泰城, 川戸 佳

  日本内分泌学会雑誌 (一社)日本内分泌学会 77 (2) 310 - 310 0029-0661 2001/09
• P450研究の新展開 バイオシグナル・ジェネレーターとしての機能を考える 脳ニューロステロイドの作用とその産生を行うP450

  川戸 佳, 木本 哲也, 北条 康嗣, 服部 高明, 高橋 泰城

  生化学 (公社)日本生化学会 73 (8) 658 - 658 0037-1017 2001/08
• Synthesis and action of estradiol in rat hippocampus

  Hattori T, Hojo Y

  Seibutsu Butsuri 一般社団法人 日本生物物理学会 41 S147  2001 [Refereed]
  
• Synthesis and action of estradiol in hippocampus

  Hattori T., Takahashi T., Kawato S.

  Seibutsu Butsuri 一般社団法人 日本生物物理学会 40 S53  0582-4052 2000 [Refereed]
  

MISC

• Behavioral neuroeconomics toward a post-Covid19 society

  Takahashi T.  Proceedings of the Conference of Transdisciplinary Federation of Science and Technology  2020-  A-3-2  2020  

  For preventing and controlling Covid-19 infections, it is important to incorporate models in behavioral economics into optimal control policies. Also, the pandemic significantly impacts our psychological states such as anxiety and fear. It is therefore important to incorporate findings in neuroeconomics -- a discipline studying the neural information processing underlying economic decisions -- into policy making. In this talk, models in behavioral economics such as hyperbolic discounting are introduced in relation to decisions over the future post-Covid-19 age.
• Mathematical Physics Models for Economy Behavior Analysis

  Takahashi Taiki  JSAP Annual Meetings Extended Abstracts  2019.2-  249  -249  2019/09/04  [Invited]
  
• 解題深書 セイラーの行動経済学研究と意思決定会計学

  高橋 泰城  企業会計 = Accounting  70-  (3)  419  -422  2018/03
• Information cascade and collective experiments

  Mori S., Hisakado M., Takahashi T.  Proceedings of the Conference of Transdisciplinary Federation of Science and Technology  2017-  B-1-1  2017  

  Collective intelligence is a mechanism to aggregate information held by many agents and generate useful information. In order for the generated information to be useful, it is a sufficient condition that the agents should independently generate information to be aggregated. On the other hand, in the case of humans, as they give priority to the return of each individual, not to the accuracy of the collective intelligence, they often use social learning and imitate the choices and actions of others. Independence of information to be aggregated is not preserved and the collective intelligence mechanism does not function. We conducted an information cascade experiment using two-choice general knowledge quizzes. When quizzes are easy, collective intelligence functions and the correct answer rate improves. However, when the quizzes are difficult, it becomes random whether the correct answer rate improves or deteriorates This change is a phase transition due to a change in the number of stable states of nonlinear Polya urn process. The essence of the phase transition is whether the in uence of the rst subject's choice (Domino effect) percolates or not in the innitely long subjects' sequence.
• Rationality and intelligence in Neuroeconomics

  Takahashi T.  Proceedings of the Conference of Transdisciplinary Federation of Science and Technology  2017-  B-1-4  2017  

  Recently, neuroeconomics---a unified discipline of economics and neuroscience---has been developed. Research topics of neuroeconomics include neural processing underlying decision under risk, intertemporal choice, and social preferences. Studies in neuroeconomics have revealed that human judgment and decision making usually violates classical rationality (e.g., Kolmogorovian probability theory, exponential time-discounting, von Neumann-Morgenstern’s expected utility theory). We observed that rationality and intelligence defined in terms of neuroeconomics is related to human intelligence and rationality in terms of cognitive science. These findings are relevant to problems in financial markets, artificial intelligence, and robotics.
• A psychophysical comparison between intertemporal choices for self and others

  Shinsuke Tokuda, Taiki Takahashi  INTERNATIONAL JOURNAL OF PSYCHOLOGY  51-  353  -353  2016/07  [Not refereed][Not invited]
  
• 日本における数理心理学の展開XXI

  吉野 諒三, 高橋 泰城, 竹村 和久, 繁桝 算男, 中川 正宣  日本心理学会大会発表論文集  77-  SS-071  -SS-071  2013/09/19  [Not refereed]
  
• 26aXZD-12 Max-Min Strategy in an Information cascade Experiment

  Mori S., Hisakado M., Takahashi T.  Meeting abstracts of the Physical Society of Japan  68-  (1)  326  -326  2013/03/26
• 20pAE-13 Information cascade is phase transition ?

  Mori S., Hisakado M., Takahashi T.  Meeting abstracts of the Physical Society of Japan  67-  (2)  296  -296  2012/08/24
• 20pAE-14 Information cascade for subjects with private information

  Irie Y., Mori S., Hisakado M., Takahashi T.  Meeting abstracts of the Physical Society of Japan  67-  (2)  296  -296  2012/08/24
• Testosterone diminishes reciprocity in a trust game

  Haruto Takagishi, Taiki Takahashi, Toshio Yamagishi  NEUROSCIENCE RESEARCH  71-  E282  -E282  2011  [Not refereed][Not invited]
  
• 25pTH-11 Breaking of sure-thing principle in quantum decision theory and associated inequalities

  Dehare H., Takahashi T., Cheon T.  Meeting abstracts of the Physical Society of Japan  65-  (2)  292  -292  2010/08/18
• Decisions under ambiguity: Effects of sign and magnitude

  Keigo Inukai, Taiki Takahashi  INTERNATIONAL JOURNAL OF PSYCHOLOGY  43-  (3-4)  496  -496  2008/06  [Not refereed][Not invited]
  
• Mood-congruent effects and the impact of stress hormone on prospective and social memory

  中山 義久, 高橋 泰城, Radford Mark H. B.  The Annals of the Hokkaido Psychological Society  (28)  19  -32  2005
• Expression analysis of enzymes and receptors for sex steroids in the rat brain

  Ishii H, Furukawa A, Hojo Y, Takahashi T, Kawato S  Seibutsu Butsuri  43-  (0)  S236  -S236  2003/08  [Not refereed][Not invited]
  
• 脳海馬神経伝達でのニューロステロイド効果のイメージング

  高橋泰城, 高田則雄, 渋谷啓介, 川戸佳  バイオイメージング  11-  (3)  73  -74  2002/10/21  [Not refereed][Not invited]
  
• 社会問題〜今科学は【○!10】 記憶学習機能の動的解析手法と求められる技術 脳ニューロステロイドを中心に

  川戸 佳, 木本 哲也, 高橋 泰城  バイオサイエンスとインダストリー = Bioscience & industry  60-  (6)  50  -53  2002/06/01
• 脳海馬神経に対する神経ステロイド(第4世代の神経情報伝達物質)効果のCaイメージング解析

  木本 哲也, 川戸 佳, 高橋 泰城, 服部 高明  バイオイメージング  9-  (3)  88  -89  2000/11/01
• acute effects of glucocorticoids on NMDA-induced Ca2+ signaling in hippocampal neurons

  Takahashi T., Kimoto T., Takata N., Kawato S.  Seibutsu Butsuri  40-  (1)  S211  2000/08/05  [Not refereed][Not invited]
  
• acute effects of steroids on NMDA-induced Ca^<2+> signaling in hippocampal neurons

  高橋泰城, 木本哲也, 高田則雄, 山口和彦, 川戸佳  Seibutsu Butsuri  39-  (1)  S61  1999/09/02  [Not refereed][Not invited]
  
• Steroids potentiate Nitric Oxide production in rat hippocampal CA1 region: Real-time fluorescence microscopic imaging

  Takata N., Kimoto T., Takahashi T., Kojima H., Kominami S., Nagano T., Kawato S.  Seibutsu Butsuri  39-  (1)  S209  1999/09/02  [Not refereed][Not invited]
  
• Mechanisms of Glia Neuron Communication and Emotional Brain : steroid/Ca/NO signal

  Kawato S., Kimoto T., Takahashi T., Takata N.  Biophysics  38-  (2)  S103  1998/09/07  [Not refereed][Not invited]
  
• Reguration of Ca^<2+> signaling via glutamate receptors in rat hippocampal neurons by steroids

  Takahashi T., Kimoto T., Takata N., Yamaguchi K., Kawato S.  Biophysics  38-  (2)  S136  1998/09/07  [Not refereed][Not invited]
  
• Real-time fluorescence microscopic imaging of Nitric Oxide signal in Rat brain cultured neurons.

  Takata N., Kimoto T., Takahashi T., Kojima H., Nagano T., Kawato S.  Biophysics  38-  (2)  S137  1998/09/07  [Not refereed][Not invited]
  

Books etc

• セルフ・コントロールの心理学 : 自己制御の基礎と教育・医療・矯正への応用

  高橋 雅治, 高橋泰城 
  北大路書房 2017 (ISBN: 9784762829734)
• 時間・自己・物語

  信原 幸弘, 佐金 武, 太田 紘史, 中山 康雄, 伊佐敷 隆弘, 米田 英嗣, 福田 敦史, 高橋 泰城 
  春秋社 2017 (ISBN: 9784393323700)
• 思春期学

  笠井 清登, 藤井 直敬, 福田 正人, 長谷川 真理子, 長谷川 寿一, 高橋泰城 
  東京大学出版会 2015 (ISBN: 9784130111416)
• 時を編む人間 : 人文科学の時間論

  田山 忠行, 小川 健二, 高橋 泰城, 野村 益寛, 権 錫永, 小杉 康, 田口 茂, 千葉 恵 
  北海道大学出版会 2015 (ISBN: 9784832933941)
• Hayek and Behavioral Economics (Archival Insights into the Evolution of Economics)

  Roger Frantz, Robert Leeson (Hayek's sensory order, gestalt neuroeconomics and quantum psychophysics)
  Palgrave Macmillan 2013/01 369

  
• リチャード・セイラーの行動経済学研究と意思決定会計学

  高橋 泰城 
  Accounting(企業会計) 2017年 12 月号

Presentations

• COVID-19とデータ科学  [Invited]

  高橋 泰城

  統計数理研究所公開シンポジウム  2023/03  オンライン  統計数理研究所
  
• 科学技術と社会とのコミュニケーション  [Invited]

  本多 敏, 西浦 博, 高橋 泰城, 松井 知子

  第15回日本統計学会春季集会  2021/03
• 行動神経経済学の医療イノベーションへの応用  [Invited]

  高橋泰城

  横幹技術フォーラム 第57回  2020/12  横幹技術協議会、横幹連合
  
• Moodleを利用した学生向けオンラインCOVID-19健康教育ツールについて

  川原由佳子, 高橋泰城

  第58回全国大学保健管理研究集会  2020/11  京都市勧業館みやこめっせ  公益社団法人 全国大学保健管理協会 国立大学法人 京都大学
  
• Hayek’s Sensory Order, Gestalt Neuroeconomics, and Quantum Psychophysics  [Invited]

  Taiki Takahashi

  Institute for Economic Studies, Keio University. Applied Economics Workshop  2020/10
• 行動神経経済学とAI研究  [Invited]

  高橋 泰城

  人工知能学会全国大会(第34回)  2020/06
• 高齢化社会への行動神経経済学の応用  [Invited]

  高橋泰城

  経団連 21世紀政策研究所  2019/11
• 経済行動分析のための数理物理モデル

  高橋 泰城

  応用物理学会秋季学術講演会  2019/09
• ベーシック・インカムと行動経済学

  高橋泰城, 武川正吾, 村上慎司

  行動経済学会 第１２回大会  2018/12
• 神経経済学・量子意思決定論による行動分析の展開  [Invited]

  高橋泰城

  日本行動計量学会第46回大会  2018/09  慶應義塾大学三田キャンパス
• Neural and Quantum Computation in Decision Making over Time and under Uncertainty  [Invited]

  Taiki Takahashi

  Unconventional Computation and Natural Computation - 17th International Conference  Fontainebleau, France
• 意思決定・社会性の行動神経経済学・量子意思決定理論  [Invited]

  高橋泰城

  電子情報通信学会  2017/08  ピパの湯 ゆ～りん館（北海道美唄市）
• 神経経済学の応用  [Not invited]

  高橋泰城

  第７回横幹連合コンファレンス  2016/11  慶應義塾大学 日吉キャンパス
  
• Psychophysical neuroeconomics: bio-psycho-social preferences  [Invited]

  Taiki Takahashi

  Collective behaviour in the big data era: can we enhance collective intelligence in human groups?  2016/04  Toulouse  Adrien BLANCHET, Matthieu ROY, Clément SIRE, Guy THERAULAZ
  
• Integrating Neuroscience and Mathematics to Elucidate Mental Activities  [Invited]

  Takahashi Taiki

  AAAS American Association for Advances in Science  2016/02  ワシントンDC
• ニューロエコノミクスセミナー ～ 消費者の「本質」に迫る新たなマーケティングの可能性 ～

  高橋 泰城

  ワテラスコモンホール(神田)  株式会社NTTデータ経営研究所
  
• 情報カスケードにおけるドミノ効果の計測  [Not invited]

  守真太郎, 日野雅文, 久門正人, 高橋泰城

  計測自動制御学会システム・情報部門学術講演会講演論文集(CD-ROM)  2014/11
• 時間知覚と聴覚sustained fieldの相関  [Not invited]

  宮崎茜, HAN Ruokang, 角屋智香, 高橋泰城, 久住一郎, 横澤宏一

  日本生体磁気学会誌  2014/05
• Molecular Neuroeconomics of Crime and Punishment  [Invited]

  Taiki Takahashi

  The 7th ECPR General Conference  2013/09  Bordeaux
• Toward a general theory of decision making  [Invited]

  Takahashi Taiki

  THIRD SYMPOSIUM ON BIOLOGY OF DECISION MAKING (SBDM 2013)  2013/05
• 2択クイズの情報カスケード実験とゲーム論的最適戦略  [Not invited]

  守真太郎, 久門正人, 高橋泰城

  日本物理学会講演概要集  2013/03
• 自己情報がある場合の情報カスケード実験  [Not invited]

  入江洋介, 守真太郎, 久門正人, 高橋泰城

  日本物理学会講演概要集  2012/08
• 情報カスケード転移の検証  [Not invited]

  守真太郎, 久門正人, 高橋泰城

  日本物理学会講演概要集  2012/08
• Full day tutorial on Quantum models of cognition and decision  [Invited]

  Jerome R. Busemeyer, Peter Bruza, Taiki Takahashi, Jennifer Trueblood

  34th Annual Meeting of the Cognitive Science Society  Sapporo, Japan
• サイコパス傾向にみられる近視眼性に関する研究  [Not invited]

  西中宏吏, 高橋泰城, 福井裕輝

  国立精神・神経医療研究センター精神保健研究所年報  2012/03
• 量子的意思決定論におけるSure Thing Principleの破れと不等式  [Not invited]

  出晴裕子, 高橋泰城, CHEON T

  日本物理学会講演概要集  2010/08
• サイコパス傾向にみられる近視眼性に関する研究  [Not invited]

  西中宏吏, 高橋泰城, 牧野貴樹, 福井裕輝

  司法精神医学  2010/03
• 不確実な環境下における行動選択の解明―確率割引モデルによる分析―  [Not invited]

  牧野貴樹, 高橋泰城, 福井裕輝

  国立精神・神経センター精神保健研究所年報  2009/03
• サイコパス傾向と脳内意思決定メカニズム―強化学習理論を用いた記述  [Not invited]

  牧野貴樹, 高橋泰城, 福井裕輝

  司法精神医学  2009/03
• Iowa Gambling Task行動選択と確率に対する認知的確率割引の相関分析  [Not invited]

  牧野貴樹, 高橋泰城, 西中宏吏, 福井裕輝

  日本生物学的精神医学会プログラム・講演抄録  2009
• サイコパス傾向にみられる意思決定:ニューロエコノミクスによる検討  [Not invited]

  西中宏吏, 高橋泰城, 牧野貴樹, 福井裕輝

  日本生物学的精神医学会プログラム・講演抄録  2009
• 抑うつと衝動性の関係についての研究  [Not invited]

  大野秀実, RADFORD Mark. H. B, 高橋泰城

  日本心理学会大会発表論文集  2007/07
• 社会的記憶のストレスホルモンによる制御と対人信頼度  [Not invited]

  高橋泰城

  日本内分泌学会雑誌  2006/09
• 展望的記憶および社会的記憶における気分一致効果とストレスホルモンの影響  [Not invited]

  中山義久, 高橋泰城, ラドフォード マーク・H

  北海道心理学研究  2005/11
• 気分一致効果とストレスホルモンが展望的および社会的記憶に与える影響  [Not invited]

  北海道心理学研究  2005
• ラット脳海馬における環境ホルモンビスフェノール‐Aの作用の解析  [Not invited]

  田辺伸聡, 高橋泰城, 岡田和し, 船江良彦, 川戸佳

  日本内分泌かく乱化学物質学会研究発表会要旨集  2003/12
• 脳海馬における細胞内シグナル伝達系の,環境ホルモンによるかく乱作用の解析  [Not invited]

  田辺伸聡, 服部高明, 高橋泰城, 川戸佳

  日本内分泌かく乱化学物質学会研究発表会要旨集  2002/11
• 女性ホルモンや環境ホルモンのラット海馬長期増強に対する作用機構  [Not invited]

  高橋泰城, 野沢知則, 高田則雄, 川戸佳

  日本内分泌かく乱化学物質学会研究発表会要旨集  2002/11
• 脳海馬神経細胞における細胞内シグナル伝達系の,環境ホルモンによるかく乱作用の解析  [Not invited]

  田辺伸聡, 服部高明, 高橋泰城, 川戸佳

  日本生物物理学会年会講演予稿集  2002/11
• 脳海馬神経伝達でのニューロステロイド効果のイメージング  [Not invited]

  高橋泰城, 高田則雄, 渋谷啓介, 川戸佳

  バイオイメージング  2002/10
• 社会問題 今科学は 10) 記憶学習機能の動的解析手法と求められる技術 脳ニューロステロイドを中心に  [Not invited]

  川戸佳, 木本哲也, 高橋泰城

  バイオサイエンスとインダストリー  2002/06
• 海馬における17β‐エストラジオール合成とその作用  [Not invited]

  服部高明, 小南思郎, 北条泰嗣, 高橋泰城, 川戸佳

  日本生物物理学会年会講演予稿集  2001/10
• 天然および合成ストレスホルモンが海馬神経細胞に与える急性作用の解析  [Not invited]

  高橋泰城, 木本哲也, 安松信明, 田辺伸聡, 川戸佳

  日本神経科学大会プログラム・抄録集  2001/09
• 海馬における17β‐エストラジオール合成とその作用  [Not invited]

  服部高明, 小南思郎, 北条泰嗣, 高橋泰城, 川戸佳

  日本内分泌学会雑誌  2001/09
• 天然および合成ストレスホルモンが海馬神経細胞に与える急性作用の解析  [Not invited]

  高橋泰城, 木本哲也, 安松信明, 田辺伸聡, 川戸佳

  神経化学  2001/09
• 脳ニューロステロイドの作用とその産生を行うP450  [Not invited]

  川戸佳, 木本哲也, 北条康嗣, 服部高明, 高橋泰城

  生化学  2001/08
• 脳海馬神経に対する神経ステロイド(第4世代の神経情報伝達物質)効果のCaイメージング解析  [Not invited]

  川戸佳, 高橋泰城, 服部高明, 木本哲也

  バイオイメージング  2000/11
• 海馬神経細胞に対するコルチコステロンの急性効果  [Not invited]

  高橋泰城, 高田則雄, 服部高明, 木本哲也, 川戸佳

  日本神経科学大会プログラム・抄録集  2000/09
• 海馬ニューロンのNMDA受容体を介したカルシウム信号に対するステロイド急性効果  [Not invited]

  高橋泰城, 木本哲也, 高田則雄, 山口和彦, 川戸佳

  日本生物物理学会年会講演予稿集  1999/09
• ステロイドによる海馬スライスでのNO産生増強の可視化解析  [Not invited]

  高田則雄, 木本哲也, 高橋泰城, 小島宏建, 小南思朗, 長野哲雄, 川戸佳

  日本生物物理学会年会講演予稿集  1999/09
• ステロイドによる海馬スライスでのNO産生増強の可視化解析  [Not invited]

  高田則雄, 木本哲也, 高橋泰城, 小島宏建, 長野哲雄, 川戸佳

  日本神経科学大会プログラム・抄録集  1999/07
• 海馬ニューロンのグルタミン酸受容体を介したカルシウム信号のステロイドによる制御機構  [Not invited]

  高橋泰城, 木本哲也, 高田則雄, 山口和彦, 川戸佳

  日本生物物理学会年会講演予稿集  1998/09
• 培養脳神経細胞でのNO信号の蛍光顕微イメージング  [Not invited]

  高田則雄, 木本哲也, 高橋泰城, 小島宏建, 長野哲雄, 川戸佳

  日本生物物理学会年会講演予稿集  1998/09
• グリアと神経細胞の交信機構と情動脳(ステロイド/Ca/NO信号)  [Not invited]

  川戸佳, 木本哲也, 高橋泰城, 高田則雄

  日本生物物理学会年会講演予稿集  1998/09
• 副腎皮質細胞と脳細胞における細胞間Ca波のイメージング  [Not invited]

  高橋泰城, 木本哲也, 阿相ひろ晃, 西村大助, 川戸佳

  バイオイメージング  1997/10

Association Memberships

• 日本アルコール・薬物医学会   日本人間行動進化学会   生物物理学会   行動経済学会   JAPANESE MEDICAL SOCIETY OF ALCOHOL & DRUG STUDIES   

Research Projects

• Study on a methodology that gives a bird's-eye view of interdisciplinary relationships based on statistics and machine learning

  Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Research (Pioneering)

  Date (from‐to) : 2021/07 -2025/03 

  Author : 松井 知子, 村上 大輔, 椿 広計, 高橋 泰城, 船渡川 伊久子, 山形 与志樹

   

  COVID-19のパンデミックが世界経済に与える影響は、2008年の世界金融危機よりも深刻であり、COVID-19が経済や気候に与える影響を予測することは、現在、大きな関心事となっている。本研究では、経済への確率的ショックを含むように拡張したDICE（Dynamic Integrated Climate-Economy）モデルを用いて、COVID-19のようなショックイベントが経済や気候に与える影響を検討した。DICEモデルの基礎となる状態変数に確率的な要素を取り入れ、再帰的な動的計画問題として解くことを試みた。ショックイベントによって引き起こされるジャンププロセスとして、離散的な確率的ショック変数を追加してDICEモデルを拡張し、ストレス状態と通常状態における経済をモデル化した。この拡張モデルをショックイベントが100年に1度ランダムに発生し、それが5年間続くと仮定して、最適確率制御問題としていくつかのシナリオで解いた。その結果、各ショックイベント後に世界の総生産が完全に回復するならば、COVID-19のショックイベントが気温や炭素濃度に与える影響は、保守的に5年間で年間の総生産が10%減少した場合でも重大ではないことを示した。しかし、ショックイベントによって生産高が5％減少し、再帰的に生産性の低下をもたらして次の期間に伝播した場合には、長期的な気温低下は0.1℃であるものの、炭素濃度に与える影響は大きいことを示した。決定論的なDICEモデルを用いた場合には、気温低下はより大きくなることを示した（約0.25℃）。
• 脳領域／個体／集団間のインタラクション創発原理の解明と適用

  JST：CREST

  Date (from‐to) : 2017 -2022 

  Author : Ichiro Tsuda
• 集合知の情報集約過程の定量的記述と社会的学習の影響

  ソフトコンピューティング 基盤研究(C)

  Date (from‐to) : 2017/04 -2021/03 

  Author : 守真太郎
• a genealogy of self-interest

  Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)

  Date (from‐to) : 2015/04 -2018/03 

  Author : TAISHIDO Masanori, TAKAHASHI Satoshi, MURAI Akihiko

   

  This research project has been performed to clarify a genealogy of economic agents on which economics traditionally has been based, from “the birth of economics” in Scottish enlightenment to current behavioral economics or neuroeconomics. In this analysis, it has become clear that not only the historical context of the advent of “homo economicus ”or the idea of “self-interest ”is very important, but also that it has involved various and diversified images of human including altruism and sociability.
• Psycho-biological foundations of norm enforcement

  Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Exploratory Research

  Date (from‐to) : 2015/04 -2018/03 

  Author : Kiyonari Toko

   

  Endogenous testosterone (T) is generally considered to enhance social dominance, but the results of economic game experiments that have examined the relationship between decision making and T are inconsistent. We explored the relationship between pre-existing social status and salivary T level among members of a rugby team at a Japanese university, where a strong seniority norm maintains hierarchical relationships. We analyzed participants’ level of acquiescence (how much more they offered beyond the lowest offer they would accept) based on their decisions both as proposer and responder in a series of one-shot Ultimatum Games. In summary, our results consistently suggest that T may enhance socially dominant behavior among higher-status persons, and that the effect of T on lower-status persons merits further investigation.
• 単一光子を用いた意思決定機能構築の研究

  光工学・光量子科学 挑戦的萌芽

  Date (from‐to) : 2015/04 -2018/03 

  Author : 成瀬誠

   

  意思決定問題は、情報通信技術の広範かつ重要な応用の根底にあり、機械学習・人工知能の基礎問題として熱心に研究されている。しかし、動的に変化する不確実な環境での意思決定とは、ベターな選択肢の探索と速やかな決断という難しいトレードオフを孕んだ「多本腕バンディット問題（Multi-armed bandit problem (MAB)」であり、その解決は容易ではない。本研究提案者らは、世界に先駆けてMABを近接場光を介した光励起輸送を用いて解決可能であることを発見した（Sci. Rep. 2013）。本研究の目的は、光の量子性をさらに積極利用することにより、人工知能の時代における光及び光技術による新たな価値として、単一光子を用いた意思決定機能の可能性を示すことである。本年度は、フランス・グルノーブルの研究チームと連携し、単一光子の確率性と粒子性を基礎として、ナノダイヤモンドを用いた単一光子源と偏光制御を用いた独自のシステムを構築し、的確で速やかな意思決定を物理的に実現することに世界で初めて成功した。単一光子の場としての性質（非局所性）が探索に活かされ、粒子としての性質が決断に直結している。本研究はScientific Reports誌に掲載され、内外の多くのメディアに報道された。中でもMIT Technology Review誌は“First Demonstration of Photonic Intelligence（世界発の光知能）”として大きく取り上げた。また、これらの結果を踏まえた理論モデル構築に着手した。
• Adolescent Mind & Self-Regulation, steering committee

  Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)

  Date (from‐to) : 2011/04 -2016/03 

  Author : Kasai Kiyoto, HASEGAWA Mariko, TAKAHASHI Taiki, NISHIDA Atsushi, SASAKI Tsukasa, Fujii Naotaka, HAGIWARA Hiroko, HASHIMOTO Ryuichiro, SAKAI Hiromu, FUKUDA Masato, OKANOYA Kazuo, YAMASAKI Syudo, YAMAWAKI Shigeto, MURAI Toshiya, TANAKA Satoshi

   

  The steering committee of the Adolescent Mind & Self-Regulation has consolidated our two key concepts, or “Adolescence” and “Self-regulation”, which evolved into a textbook “the Science of Adolescence (University of Tokyo Press)”. Comprehensive management for each research stages (A01-A03) has led to a great deal of trans-disciplinary achievements among humanities and sciences. A lot of cooperation works with other academic fields have resulted in establishment of the UTIDAM, an official multidisciplinary-research institute in University of Tokyo. The committee have also created an international network engaging in research for adolescence, and have got a leading position in East Asia. Outreach and public-relation to the public and adolescents have been emphasized throughout the study period.
• Experimental econophysics of social learning and collective intelligence

  Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research

  Date (from‐to) : 2013 -2015 

  Author : Mori Shintaro, TAKAHASHI TAIKI, HISAKADO MASATO, HINO MASAFUMI

   

  It has been considered that the social learning where agents get information from the behaviors and choices of other agents is the most important factor in the description and the understanding of social and economical phenomena. We have controlled the uncertainty of the information of human collectives in an information cascade experiment and showed that there occurs a phase transition of non-linear Polya urn. Theoretically, we clarify when the phase transition becomes continuous or discontinuous and the universality class of the former continuous one. Furthermore, we study several ideas how to increase the accuracy of collective intelligence in information cascade.
• Developmental Process of Self-Regulation in Adolescence

  Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research

  Date (from‐to) : 2011 -2015 

  Author : HIRAIWA-HASEGAWA Mariko, OKAZAKI Yuji, ANDO Shuntaro, YAMASAKI Syudo, KAORI Endo

   

  We broke into 3 teams and studied the developmental process of self-regulation. First, Tokyo TEEN Cohort team has constituted the first large-scale adolescent cohort (N=4,478) in Japan and conducted a 2-wave large scale longitudinal survey. The survey based on community, and recruited participants randomly from three municipalities in Tokyo using the resident register. Results showed that self-regulation is based on language acquisition from an early age, and develops with the maturation of understanding of vocabulary and grasp of grammar. Second, Twin study team conducted a longitudinal study at Secondary School of the Faculty of Education, the University of Tokyo, which is a combined junior high and high school and a school where many twins belong. They found factors which have impact on self-regulation of daily habits. Finally, Neuroeconomics team showed a biological foundation of self-regulation.
• Behavioral Finance and New Trends in Economic Analysis

  Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research

  Date (from‐to) : 2012 -2014 

  Author : KAMESAKA Akiko, TAKAHASHI Taiki

   

  This project aimed to proceed economic or financial analysis taking in recent results in other fields such as psychology etc., and have done researches on behavioral economics and finance. This project's output includes publication in professional journals, oral presentation at international conferences, invited speeches at international and domestic meetings. The project leader started to conduct investor survey with Prof. Robert Schiller, winner of Nobel prize.
• Time-inconsistent Behavior and Efficacy of Self-control

  Ministry of Education, Culture, Sports, Science and Technology：Grants-in-Aid for Scientific Research(基盤研究(B))

  Date (from‐to) : 2008 -2011 

  Author : Fumihiko HIRUMA, 須斎 正幸, 筒井 義郎, 池田 新介, 高橋 泰城

   

  Time discount rate is an important factor determining decision-making between present and future. The higher(lower) time discount rate implies the present-biased(future-oriented) decision-making. Our survey studies revealed that the respondents who have higher cognitive ability and stronger self-control tend to have lower time discount rate. This result implies the possibility of education as a tool to amend the time discount rate.
• Neuroeconomic studies on neurochemical bases of decision-making

  Ministry of Education, Culture, Sports, Science and Technology：Grants-in-Aid for Scientific Research(若手研究(B))

  Date (from‐to) : 2008 -2011 

  Author : Taiki TAKAHASHI

   

  Previous neuroeconomic studies employed neuroimaging techniques to examine economic decision-making processes in a manner which we can only see neural correlate of decision making processes. In this research project, we utilized psychophysical theory and quantum decision theory to extend neuroeconomic theories and elucidated molecular mechanism underlying economic decision making, which has been impossible by traditional neuroeconomic approaches.
• ニューロエコノミクスの研究拠点形成に向けて:金融理論の基盤再考

  文部科学省：科学研究費補助金(萌芽研究, 挑戦的萌芽研究)

  Date (from‐to) : 2008 -2009 

  Author : 筒井 義郎, 大竹 文雄, 藤田 一郎, 晝間 文彦, 高橋 泰城

   

  時間割引は多くの経済実験において、少額を早く受け取るオプションと多額を遅く受け取るオプションのどちらを選択するか、というタスクで測定される。本研究課題は、(1)遅れ(現在から最初のオプションまでの時間)と期間(2つのオプションの間の時間)を明示的に分離して、それぞれが時間割引に与える効果を特定する、(2)喫煙が時間割引に対してもたらす効果について明らかにする、という2つの課題を主たる目的とする。(1)については、これまでに行った実験の結果を論文にまとめ、本年度6月にJournal of Risk and Uncertaintyに掲載した。(2)については、昨年度早稲田大学で行った、非喫煙者と喫煙者、断煙者と非断煙者を比較する実験の結果を分析した。その結果、喫煙者は非喫煙者に比べて高い時間割引を示すことが明らかにされた。また、断煙者は非断煙者よりも、お金に対しては高い割引率を示すが、タバコについては、むしろ忍耐強くなるという結果を得た。この後者の結果の頑健性については疑問があり、詳細な実験条件設定に問題がある可能性を検討して、それらを改良した実験を本年1月と2月に大阪大学において実施した。その結果は現在解析中であるが、おおむね、喫煙者は非喫煙者に比べて高い時間割引を示す点にでは早稲田実験と同じである。断煙者と非断煙者を比べると、お金については両者の時間割引には差がなく、タバコについては、断煙者の方がよりせっかちになるという結果が得られた。今年度の実験結果の方が直観に整合的であるが、両方の結果をどのようにまとめていくかは検討中である。一方、fMRI実験については、早稲田大学健康科学部の正木教授の協力が得られ、本年2月と3月に、異時点間選択を行っている喫煙者の脳画像を撮像した。引き続き、行動実験の結果をまとめつつ、断煙者および非喫煙者についても撮像していく。
• 社会的認知・経済学的意思決定を制御する神経ホルモンの研究

  文部科学省：科学研究費補助金(萌芽研究)

  Date (from‐to) : 2005 -2007 

  Author : 高橋 泰城

   

  (1) 覚醒度に関連する神経ホルモンの唾液中アミラーゼや男性ホルモンのテストステロンが大きい時間割引率と関連する。(2) 時間割引の意思決定の際に知覚されている心理時間が、心理物理学で見出されている(スティーブンスのべき乗則というよりもむしろ)ウェーバー・フェヒナー則に従っていることにより、時間割引関数が(指数関数ではなく)双曲型関数によって記述されていることが考えられる。(3) 双曲型時間割引が、時間知覚に関連するドーパミン作動性神経回路の非シナプズ的電気的結合(ギャップジャンクション)によって担われているという可能性が考えられる(4) 時間割引の意思決定を、遅延報酬の受取人ではなく、ほかの人が代りにおこなうと、時間割引関数の双曲性(時間非整合性、非合理性)が強まってしまう(5) 意識下の感情が意思決定において重要な役割を果たすことを主張する「ソマティックマーカー仮説」の論拠となっているアイオワ・ギャンブリング課題における行動が、双曲型確率割引関数によって説明可能である(6) 時間割引や不確実性下の意思決定を記述する上で、Tsallis非加法的統計力学におけるq-指数関数が有効である(7) 喫煙者は、お金の分配における不平等性を嫌うほどには、タバコの分配の不平等性を嫌うわけではなく、依存性薬物と通常の報酬の価値判断を担う神経メカニズムが異なっている(8) 遅延報酬を手に入れることができる確率の主観的見積もりは、遅延時間の増加にともなって双曲型の減衰を示すが、時間割引が完全に不確実性回避に帰着されるわけではない(9) 結果の確率すら不明な不確実性下での意思決定は、結果の符号と大きさに依存し、従来提唱されてきた劣加法的主観確率仮説が完全に正しいわけではない
• 行動神経経済学

  Date (from‐to) : 2001
• 青春脳

  文部科学省：新学術領域

Social Contribution

• 内閣府 応用脳科学 コンソーシアム ＮＴＴデータ経営研究所 神経経済学 セミナーシリーズ

  Role : Lecturer