研究者データベース

高橋 泰城(タカハシ タイキ)
文学研究院 人間科学部門 行動科学分野
准教授

基本情報

所属

  • 文学研究院 人間科学部門 行動科学分野

職名

  • 准教授

学位

  • 博士(理学)(東京大学)
  • 修士(理学)(東京大学)

J-Global ID

プロフィール

  • 東京大学 理学系研究科 物理学専攻 博士(理学)


    応用数学、人間適応生理学、行動経済学、行動ファイナンスの学術誌編集委員、国際量子科学技術相互推進組織(Quantum Interaction http://www.quantuminteraction.org/ )メンバー Organisation for Economic Co-operation and Development (MyOECDメンバー)環境省ナッジユニット(ベストナッジ賞選考委員)、日立北大ラボ連携研究

研究キーワード

  • 情報科学(量子情報論理)   応用数学   神経法学   社会物理   神経経済学   

研究分野

  • 人文・社会 / 認知科学 / 神経経済学、量子意思決定論、神経法学

学歴

  •         - 2001年   東京大学   理学系研究科   物理学専攻 理学博士
  •         - 2001年   東京大学
  •         - 1998年   東京大学   理学系研究科   物理学専攻 理学修士
  •         - 1998年   東京大学
  •         - 1996年   東京大学   理学部   物理学科 卒業 理学士
  •         - 1996年   東京大学
  •         - 1992年   開成高等学校 卒業

所属学協会

  • 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   

研究活動情報

論文

  • Brian C Howatt, María José Muñoz Torrecillas, Salvador Cruz Rambaud, Taiki Takahashi
    Frontiers in public health 7 165 - 165 2019年 [査読有り][通常論文]
     
    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.
  • Sarah E Stegall, Tyler Collette, Takuji Kinjo, Taiki Takahashi, Paul Romanowich
    Frontiers in public health 7 297 - 297 2019年 [査読有り][通常論文]
     
    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.
  • 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 2018年04月03日 [査読有り][通常論文]
     
    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.
  • María J Muñoz Torrecillas, Salvador Cruz Rambaud, Taiki Takahashi
    Frontiers in public health 6 176 - 176 2018年 [査読有り][通常論文]
     
    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.
  • Taiki Takahashi, Song-Ju Kim, Makoto Naruse
    Progress in biophysics and molecular biology 130 Pt A 103 - 105 2017年11月 [査読有り][通常論文]
     
    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.
  • Taiki Takahashi
    Progress in biophysics and molecular biology 130 Pt A 99 - 102 2017年11月 [査読有り][通常論文]
     
    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.
  • Yukako Inoue, Taiki Takahashi, Robert P Burriss, Sakura Arai, Toshikazu Hasegawa, Toshio Yamagishi, Toko Kiyonari
    Scientific reports 7 1 5335 - 5335 2017年07月13日 [査読有り][通常論文]
     
    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.
  • Salvador Cruz Rambaud, María J Muñoz Torrecillas, Taiki Takahashi
    Frontiers in pharmacology 8 416 - 416 2017年 [査読有り][通常論文]
     
    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.
  • Takayuki Fujii, Joanna Schug, Kuniyuki Nishina, Taiki Takahashi, Hiroyuki Okada, Haruto Takagishi
    Scientific reports 6 38662 - 38662 2016年12月08日 [査読有り][通常論文]
     
    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.
  • Keiko Ishii, Lili Gang, Taiki Takahashi
    Neuro endocrinology letters 37 6 427 - 432 2016年11月 [査読有り][通常論文]
     
    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.
  • Masafumi Hino, Yosuke Irie, Masato Hisakado, Taiki Takahashi, Shintaro Mori
    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN 85 3 2016年03月 [査読有り][通常論文]
     
    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.
  • Yu Ohmura, Taiki Takahashi, Nozomi Kitamura
    Behavioral Economics of Preferences, Choices, and Happiness 179 - 196 2016年01月01日 [査読有り][通常論文]
     
    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.
  • Taiki Takahashi
    Behavioral Economics of Preferences, Choices, and Happiness 117 - 122 2016年01月01日 [査読有り][通常論文]
     
    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.
  • Tomokazu Tsurugizawa, Shinsuke Tokuda, Tokiko Harada, Taiki Takahashi, Norihiro Sadato
    PloS one 11 4 e0154083  2016年 [査読有り][通常論文]
     
    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.
  • Shintaro Mori, Masafumi Hino, Masato Hisakado, Taiki Takahashi
    PROCEEDINGS OF ECCS 2014: EUROPEAN CONFERENCE ON COMPLEX SYSTEMS 1 - 10 2016年 [査読有り][通常論文]
     
    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.
  • Nobuye Ishibashi-Ohmura, Taiki Takahashi
    NeuroQuantology 13 3 293 - 298 2015年09月01日 [査読有り][通常論文]
     
    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.
  • Chong Chen, Taiki Takahashi, Shin Nakagawa, Takeshi Inoue, Ichiro Kusumi
    Neuroscience and biobehavioral reviews 55 55 247 - 67 2015年08月 [査読有り][通常論文]
     
    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.
  • Bo Hou, Mariko Murata, Ahmad Shah Said, Hiroshi Sakaida, Sawako Masuda, Taiki Takahashi, Zhe Zhang, Kazuhiko Takeuchi
    Allergy & rhinology (Providence, R.I.) 6 1 33 - 8 2015年01月 [査読有り][通常論文]
     
    Japanese cedar pollinosis is the predominant seasonal allergic rhinitis in Japan, and it has increased in prevalence during the past 10 years. Sublingual immunotherapy (SLIT) is considered a safe and effective treatment for pollinosis. Micro-RNAs (miRNAs) are a class of short single-stranded RNA molecules that posttranscriptionally silence gene expression and may mediate allergic immune responses. The aim of this study was to investigate the miRNA alteration in asymptomatic subjects sensitized to Japanese cedar pollen under prophylactic SLIT under part of a randomized, double-blind, placebo-controlled, multiple-center trial. Analysis was undertaken in 15 asymptomatic subjects sensitized to Japanese cedar pollen-specific IgE (ImmunoCAP class ≥2) who participated in 2013. The SLIT group (n = 6) received standardized Japanese cedar pollen extract and the placebo group (n = 9) received an inactive placebo for 5 months covering the cedar pollen season. Changes in serum miRNAs were measured by real-time quantitative polymerase chain reaction to determine whether SLIT had effects on profiles of circulating miRNA. Seven subjects in the placebo group developed pollinosis symptoms, whereas no subjects in the SLIT group did (p = 0.007). Serum hsa-miR-223 was significantly up-regulated in postseason compared with preseason samples. The hsa-let-7b was significantly more down-regulated in postseason than in preseason samples from the placebo group; however, no significant differences were observed in those from the SLIT group. A significant decrease in circulating let-7b was also observed in the subjects who developed symptoms. Prophylactic SLIT was effective in preventing the development of pollinosis. Alterations in miRNA expression occurred in asymptomatic, sensitized subjects during cedar pollen season.
  • 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 2015年 [査読有り][通常論文]
     
    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.
  • Chong Chen, Taiki Takahashi, Si Yang
    Frontiers in psychology 6 222 - 222 2015年 [査読有り][通常論文]
  • Taiki Takahashi, Shinsuke Tokuda, Masato Nishimura, Ryo Kimura
    ENTROPY 16 10 5537 - 5545 2014年10月 [査読有り][招待有り]
     
    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.
  • Taiki Takahashi
    Topics in cognitive science 6 1 104 - 7 2014年01月 [査読有り][通常論文]
     
    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.
  • Taiki Takahashi, Haruto Takagishi, Hirofumi Nishinaka, Takaki Makino, Hiroki Fukui
    Neuro endocrinology letters 35 6 510 - 7 2014年 [査読有り][通常論文]
     
    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.
  • Shintaro Mori, Masato Hisakado, Taiki Takahashi
    Journal of the Physical Society of Japan 82 8 2013年08月 [査読有り][通常論文]
     
    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.
  • Shoko Yamane, Hiroyasu Yoneda, Taiki Takahashi, Yoshio Kamijo, Yasuhiro Komori, Fumihiko Hiruma, Yoshiro Tsutsui
    Journal of Socio-Economics 45 47 - 56 2013年08月 [査読有り][通常論文]
     
    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.
  • 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 2013年03月 [査読有り][通常論文]
     
    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.
  • Taiki Takahashi
    Neuro endocrinology letters 34 7 615 - 7 2013年 [査読有り][通常論文]
     
    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.
  • Taiki Takahashi, Ruokang Han
    Applied Mathematics 4 11 1520 - 1525 2013年 [査読有り][通常論文]
     
    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年 [査読有り][通常論文]
  • Towards a physical theory of quantum decision making.
    Taiki Takahashi
    Topics in Cognitive Science 2013年 [査読有り][招待有り]
  • 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年 [査読有り][通常論文]
  • The q-Exponential Social Discounting Functions of Gain and Loss
    T Takahashi
    Applied Mathematics 4, 445-448 2013年 [査読有り][通常論文]
  • 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年 [査読有り][通常論文]
  • 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年 [査読有り][通常論文]
  • 高橋 泰城
    科学哲学 46 2 17 - 30 2013年 [査読有り][招待有り]
  • Ruokang Han, Taiki Takahashi
    PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIONS 391 24 6568 - 6576 2012年12月 [査読有り][通常論文]
     
    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年12月 [査読有り][通常論文]
  • Emotion Interference Solves Social Dilemma
    Taiki Takahashi
    Theoretical Economics Letters 2, 446-449 2012年12月 [査読有り][通常論文]
  • A nonlinear neural population coding theory of quantum cognition and decision making
    Takahashi Taiki, Taksu Cheon
    World Journal of Neuroscience 2, 183 - -186 2012年12月 [査読有り][通常論文]
  • Taksu Cheon, Taiki Takahashi
    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN 81 10 2012年10月 [査読有り][通常論文]
     
    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.
  • Shintaro Mori, Masato Hisakado, Taiki Takahashi
    Physical review. E, Statistical, nonlinear, and soft matter physics 86 2 Pt 2 026109 - 026109 2012年08月 [査読有り][通常論文]
     
    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 5 10-14  2012年08月 [査読有り][招待有り]
  • Tempospect Theory of Intertemporal Choice
    Takahashi Taiki, Ruokang Han
    Psychology 3 (8) 555-557 - 555-557 2012年08月 [査読有り][通常論文]
  • Taiki Takahashi
    Neuro endocrinology letters 33 7 667 - 73 2012年 [査読有り][通常論文]
     
    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.
  • Taiki Takahashi
    NEUROQUANTOLOGY 10 4 688 - 691 2012年 [査読有り][通常論文]
     
    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.
  • 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年11月 [査読有り][通常論文]
     
    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
    ...
  • Taiki Takahashi
    PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIONS 390 5 902 - 905 2011年03月 [査読無し][通常論文]
     
    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.
  • Taiki Takahashi
    NEUROENDOCRINOLOGY LETTERS 32 3 221 - 225 2011年 [査読無し][通常論文]
     
    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年 [査読無し][通常論文]
  • Taksu Cheon, Taiki Takahashi
    PHYSICS LETTERS A 375 2 100 - 104 2010年12月 [査読有り][通常論文]
     
    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.
  • Taiki Takahashi
    MEDICAL HYPOTHESES 75 4 393 - 396 2010年10月 [査読無し][通常論文]
     
    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.
  • Taiki Takahashi
    MEDICAL HYPOTHESES 75 4 356 - 358 2010年10月 [査読無し][通常論文]
     
    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.
  • Taiki Takahashi
    PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIONS 389 17 3600 - 3603 2010年09月 [査読無し][通常論文]
     
    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.
  • 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 2010年 [査読無し][通常論文]
     
    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.
  • 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 2010年 [査読無し][通常論文]
     
    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.
  • 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 2010年 [査読無し][通常論文]
     
    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.
  • Taiki Takahashi
    Journal of Neuroscience, Psychology, and Economics 2 2 75 - 90 2009年11月 [査読有り][通常論文]
     
    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.
  • Taiki Takahashi
    PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIONS 388 5 715 - 719 2009年03月 [査読無し][通常論文]
     
    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.
  • Taiki Takahashi, Tarik Hadzibeganovic, Sergio A. Cannas, Takaki Makino, Hiroki Fukui, Shinobu Kitayama
    NEUROENDOCRINOLOGY LETTERS 30 2 185 - 191 2009年02月 [査読無し][通常論文]
     
    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年 [査読無し][通常論文]
  • Keigo Inukai, Taiki Takahashi
    INTERNATIONAL JOURNAL OF NEUROSCIENCE 119 8 1170 - 1178 2009年 [査読無し][通常論文]
     
    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.
  • Taiki Takahashi, Yu Ohmura, Hidemi Oono, Mark Radford
    NEUROENDOCRINOLOGY LETTERS 30 6 749 - 752 2009年 [査読無し][通常論文]
     
    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.
  • Haruto Takagishi, Takayuki Fujii, Shinya Kameshima, Michiko Koizumi, Taiki Takahashi
    NEUROENDOCRINOLOGY LETTERS 30 5 643 - 646 2009年 [査読無し][通常論文]
     
    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.
  • Haruto Takagishi, Taiki Takahashi, Akira Toyomura, Nina Takashino, Michiko Koizumi, Toshio Yamagishi
    NEUROENDOCRINOLOGY LETTERS 30 4 496 - 500 2009年 [査読無し][通常論文]
     
    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.
  • Taiki Takahashi
    NEUROENDOCRINOLOGY LETTERS 29 4 399 - 404 2008年08月 [査読無し][通常論文]
     
    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.
  • Taiki Takahashi, Koki Ikeda, Toshikazu Hasegawa
    NEUROENDOCRINOLOGY LETTERS 29 4 451 - 453 2008年08月 [査読無し][通常論文]
     
    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.
  • 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 2008年06月 [査読無し][通常論文]
     
    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.
  • Taiki Takahashi, Hidemi Oono, Mark H. B. Radford
    PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIONS 387 8-9 2066 - 2074 2008年03月 [査読無し][通常論文]
     
    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.
  • Taiki Takahashi
    PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIONS 387 2-3 551 - 556 2008年01月 [査読無し][通常論文]
     
    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.
  • Taiki Takahashi, Kikue Sakaguchi, Mariko Oki, Toshikazu Hasegawa
    Journal of Neuroscience, Psychology, and Economics 1 1 7 - 16 2008年 [査読無し][通常論文]
     
    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.
  • Taiki Takahashi
    PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIONS 386 1 335 - 338 2007年12月 [査読無し][通常論文]
     
    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.
  • Talki Takahashi
    PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIONS 385 2 637 - 644 2007年11月 [査読無し][通常論文]
     
    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.
  • Taiki Takahashi, Koki Ikeda, Toshikazu Hasegawa
    NEUROENDOCRINOLOGY LETTERS 28 5 662 - 665 2007年10月 [査読無し][通常論文]
     
    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.
  • Taiki Takahashi
    NEUROENDOCRINOLOGY LETTERS 28 5 659 - 661 2007年10月 [査読無し][通常論文]
     
    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.
  • Taiki Takahashi, Koki Ikeda, Toshikazu Hasegawa
    BEHAVIORAL AND BRAIN FUNCTIONS 3 52  2007年09月 [査読無し][通常論文]
     
    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.
  • Yoshihisa Nakayama, Taiki Takahashi, Akio Wakabayashi, Hidemi Ono, Mark H. B. Radford
    NEUROENDOCRINOLOGY LETTERS 28 4 445 - 448 2007年08月 [査読無し][通常論文]
     
    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.
  • Taiki Takahashi, Hidemi Oono, Mark H. B. Radford
    PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIONS 381 338 - 342 2007年07月 [査読無し][通常論文]
     
    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.
  • Taiki Takahashi, Hidemi Oono, Mark Hb Radford
    BEHAVIORAL AND BRAIN FUNCTIONS 3 20  2007年04月 [査読無し][通常論文]
     
    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.
  • Taiki Takahashi, Aizo Furukawa, Tomohiro Miyakawa, Hitoshi Maesato, Susumu Higuchi
    NEUROENDOCRINOLOGY LETTERS 28 2 131 - 136 2007年04月 [査読無し][通常論文]
     
    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.
  • Taiki Takahashi, Koki Ikeda, Hirokata Fukushima, Toshikazu Hasegawa
    NEUROENDOCRINOLOGY LETTERS 28 1 17 - 20 2007年02月 [査読有り][通常論文]
     
    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.
  • Taiki Takahashi
    MEDICAL HYPOTHESES 68 1 184 - 187 2007年 [査読無し][通常論文]
     
    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.
  • Taiki Takahashi
    MEDICAL HYPOTHESES 69 1 195 - 198 2007年 [査読無し][通常論文]
     
    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.
  • Yu Ohmura, Taiki Takahashi, Nozomi Kitamura, Paul Wehr
    EXPERIMENTAL AND CLINICAL PSYCHOPHARMACOLOGY 14 3 318 - 328 2006年08月 [査読無し][通常論文]
     
    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.
  • Taiki Takahashi, Kikue Sakaguchi, Mariko Oki, Seijiro Homma, Toshikazu Hasegawa
    NEUROENDOCRINOLOGY LETTERS 27 4 439 - 444 2006年08月 [査読無し][通常論文]
     
    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.
  • Keigo Inukai, Taiki Takahashi
    Medical Hypotheses 67 2 283 - 286 2006年 [査読無し][通常論文]
     
    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.
  • T Takahashi
    MEDICAL HYPOTHESES 67 1 183 - 186 2006年 [査読無し][通常論文]
     
    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.
  • T Takahashi
    MEDICAL HYPOTHESES 67 2 276 - 279 2006年 [査読無し][通常論文]
     
    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.
  • Taiki Takahashi
    MEDICAL HYPOTHESES 67 6 1372 - 1374 2006年 [査読無し][通常論文]
     
    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.
  • T Takahashi
    BRAIN RESEARCH BULLETIN 67 5 398 - 402 2005年11月 [査読無し][通常論文]
     
    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.
  • Y Ohmura, T Takahashi, N Kitamura
    PSYCHOPHARMACOLOGY 182 4 508 - 515 2005年11月 [査読無し][通常論文]
     
    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.
  • Y Nakayama, T Takahashi, MHB Radford
    NEUROENDOCRINOLOGY LETTERS 26 5 599 - 602 2005年10月 [査読無し][通常論文]
     
    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.
  • T Takahashi, K Ikeda, M Ishikawa, N Kitamura, T Tsukasaki, D Nakama, T Kameda
    NEUROENDOCRINOLOGY LETTERS 26 4 351 - 354 2005年08月 [査読無し][通常論文]
     
    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.
  • T Takahashi, K Ikeda, M Ishikawa, N Kitamura, T Tsukasaki, D Nakama, T Kameda
    NEUROREPORT 16 2 197 - 199 2005年02月 [査読有り][通常論文]
     
    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.
  • Takahashi T, Ikeda K, Ishikawa M, Kitamura N, Tsukasaki T, Nakama D, Kameda T
    NeuroReport 16 197 - 199 2005年 [査読無し][通常論文]
  • T Takahashi
    MEDICAL HYPOTHESES 65 4 691 - 693 2005年 [査読無し][通常論文]
     
    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.
  • T Takahashi
    NEUROREPORT 15 13 2145 - 2147 2004年09月 [査読無し][通常論文]
     
    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.
  • T Takahashi, K Ikeda, M Ishikawa, T Tsukasaki, D Nakama, S Tanida, T Kameda
    NEUROSCIENCE LETTERS 363 2 125 - 130 2004年06月 [査読無し][通常論文]
     
    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.
  • 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 2003年02月17日 [査読有り][通常論文]
     
    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.
  • 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 2003年02月 [査読無し][通常論文]
     
    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.
  • T Takahashi, T Kimoto, N Tanabe, TA Hattori, N Yasumatsu, S Kawato
    JOURNAL OF NEUROCHEMISTRY 83 6 1441 - 1451 2002年12月 [査読無し][通常論文]
     
    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.

書籍

講演・口頭発表等

その他活動・業績

受賞

  • 2012年12月 行動経済学会 奨励賞
  • 2007年 Best paper award (Association for Neuropsychoeconomics)
  • 2005年 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

共同研究・競争的資金等の研究課題

  • 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 科学技術振興事業団:JST戦略的創造研究推進事業
    研究期間 : 2017年 -2022年 
    代表者 : 津田一郎
  • ソフトコンピューティング 基盤研究(C)
    研究期間 : 2017年04月 -2021年03月 
    代表者 : 守真太郎
  • 光工学・光量子科学 挑戦的萌芽
    研究期間 : 2015年04月 -2018年03月 
    代表者 : 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。
  • 文部科学省:科学研究費補助金(挑戦的萌芽研究)
    研究期間 : 2013年 -2015年 
    代表者 : 守 真太郎, 高橋 泰城
     
    情報カスケードにおいてシステムサイズ(被験者数)が無限大の極限で、集団選択が必ず正しくなるのか、誤る確率が正なのかを明らかにした。結論は、二択のクイズを用いた場合、クイズの難易度がある臨界値を超えた場合、壺の選択では実験を実施したすべての場合で、集団選択が誤る確率が正であることを示した。二択のクイズについては、この事実はすでに我々が報告していたが、今回の結果は、この相転移現象の秩序変数のシステムサイズ依存性を理論的に明らかにした上での結果であり、集合知や社会的学習の研究において統計力学の手法の有効性を明らかにするものである。また、従来はヒトがベイズ的な推定と選択を行うなら、壺の選択問題で集団選択が誤る確率はゼロに収束するとされていたことを否定し、ヒトは合理的にハードし、その結果集団選択が間違いうることがかなり一般的な事象であることを明確にしたものである。これは、市場におけるバブルなどのマクロな現象のメカニズムを実験室実験と統計物理学の手法で物理現象として明らかにした画期的なものである。また、情報カスケードなどの非常に相関の強い二値の確率過程に対し、統計物理のスケーリングの観点から見る視点を提案しさまざまなモデルの普遍類を明らかにした。普遍類は大きく分けて3つあり、それぞれの臨界指数を厳密に評価した。また、集団知における被験者が参照できる人数と個人レベルでの正答率、緩和時間のトレードオフの関係を明らかにした。
  • 文部科学省:科学研究費補助金(新学術領域研究(研究領域提案型))
    研究期間 : 2011年 -2015年 
    代表者 : 長谷川 眞理子, 高橋 泰城, 西田 淳志, 佐々木 司
     
    【分担班】長谷川は、西田と連携しながら、東京ティーンコホートの設立と、その研究体制の確立を行った。また、最近の日本における少年犯罪のデータおよび、児童虐待事件のデータをさらに付け加え、データ入力と分析を行っている途中である。西田は、平成24年9月より、約2年間にわたる第一期訪問調査を開始した。現時点までの調査協力率は39%であり、これに基づくと平成26年8月の第一期調査終了時には約5,500名程度の10歳児コホートが構築されることが期待できる。佐々木は、東大教育学部附属中等教育学校での精神保健調査を継続・解析した。この調査は、西田・長谷川の10-11歳児の地域コホート調査と連携し、それに続く中高生の発達、生活習慣、精神的健康を調査、同年代での自己制御の発達と関連諸要因に関する縦断的解析を進めている。高橋は、時間割引における自己制御が、報酬を待っている時と損失を待っているときの待ち時間の違いによって説明できることを、数理モデルおよび行動実験により示した。また、時間割引における合理性の破れも、時間間隔の知覚の性質により説明できる理論を提唱した。【公募班】西谷は、小学生~若年成人を対象に、社会性・自己制御能力計測、内分泌機能計測、遺伝子多型計測、環境因子計測を実施し、思春期前期~中期を境に、重要な社会的刺激である表情・視線の処理様式に変化が起こる可能性を見出した。藤澤は、双生児のいる約1000家庭を対象に質問紙調査を実施した。予備的解析の結果から、行動抑制の制御・注意の制御・行動始発の制御の個人差が、遺伝要因と非共有環境要因で説明されることが示された。文東は、コホート研究のマーカーにDNAメチル化を用いるため、個人間のメチル化変動が大きいDNA部位を選択することを目的として、約100名分の健常者のDNAメチル化データを取得した。
  • 文部科学省:科学研究費補助金(基盤研究(C))
    研究期間 : 2012年 -2014年 
    代表者 : 亀坂 安紀子, 高橋 泰城
     
    本研究課題は、最新の行動ファイナンス、行動経済学、幸福度の分析を進めることを目的としており、平成24年度には以下の通り多くの成果をあげることができた。行動ファイナンス分野については、海外の共同研究者であるノアスミス氏と新たにファイナンス実験を行った他、ワシントン州立大学教授のJohn Nofsinger 氏と東日本大震災前後の投資家行動の分析を進め論文を執筆し、専門ジャーナルに投稿した。また、単著論文として執筆した震災前後の投資家行動に関する論文が、財務省財務総合政策研究所発行英文専門雑誌 Public Policy Review に掲載された。また、これらの研究結果について、海外の大学のセミナーなどで報告を行った。行動経済学分野では、日本の大規模アンケート調査のデータを使用した時間割引率についての分析結果が Psychology という専門雑誌に掲載された。もうひとつの大きな分析テーマである幸福度などの心理指標の分析では、研究を進めた結果として予想をはるかに超える成果が得られた。特に東日本大震災前後の日本人の幸福度や価値観の変化の分析結果は、海外からも注目され、その結果世界各国の政府代表やノーベル経済学賞受賞者であるスティグリッツらが参加したOECDの世界フォーラムでも報告する機会が与えられた。また、欧州経済研究所セミナー(於 スウェーデン大使館)、国内の大きなイベント(FPフェア)、大学主催シンポジウム、学会パネルディスカッション、新聞、海外メディアなど多様な媒体で研究成果を公表する機会があった。それらの研究成果の一部は、『日本の家計行動のダイナミズムVIII-東日本大震災が家計に与えた影響』 瀬古美喜・照山博司・山本勲・樋口義雄編、慶應義塾大学出版会の第9章「東日本大震災の幸福感への影響」として2012年6月に出版された。
  • 文部科学省:科学研究費補助金(基盤研究(B))
    研究期間 : 2008年 -2011年 
    代表者 : 晝間 文彦, 須斎 正幸, 筒井 義郎, 池田 新介, 高橋 泰城
     
    時間割引率は人々の現在と将来にかかわる意思決定を決める重要な要因で、時間割引率が高いほど現在を重視した(せっかちな)、低いほど将来を重視した(我慢強い)意思決定を意味する。この研究では、時間割引率がどのような要因に関係しているかをアンケートによって調べたが、時間割引率は自制力が高いほど、認知能力が高いほど、低いことが明らかとなった。これは時間割引率に対する教育の有効性を示唆するものである。
  • 文部科学省:科学研究費補助金(若手研究(B))
    研究期間 : 2008年 -2011年 
    代表者 : 高橋 泰城
     
    神経経済学の研究においては、従来、脳機能イメージング法により、意思決定と相関する神経活動を計測し、経済学的意思決定の過程を分析するという方法が主として用いられてきた。本研究計画においては、これまでの方法では解明が不可能であった、経済学的意思決定の分子機構の解明、および神経経済学の理論を拡張するため、心理物理学や量子意思決定理論の枠組みを採用し、意思決定の神経化学基盤の解明をすすめることができた。
  • 文部科学省:科学研究費補助金(萌芽研究, 挑戦的萌芽研究)
    研究期間 : 2008年 -2009年 
    代表者 : 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。
  • 文部科学省:科学研究費補助金(萌芽研究)
    研究期間 : 2005年 -2007年 
    代表者 : 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
    研究期間 : 2001年
  • 青春脳
    文部科学省:新学術領域

教育活動情報

主要な担当授業

  • 博士論文指導特殊演習
    開講年度 : 2019年
    課程区分 : 博士後期課程
    開講学部 : 文学研究科
  • 行動実験調査法特別演習
    開講年度 : 2019年
    課程区分 : 修士課程
    開講学部 : 文学研究科
    キーワード : 行動経済学、神経経済学、量子情報科学
  • 博士論文指導特殊演習Ⅰ
    開講年度 : 2019年
    課程区分 : 博士後期課程
    開講学部 : 文学院
  • 行動実験調査法特別演習
    開講年度 : 2019年
    課程区分 : 修士課程
    開講学部 : 文学研究科
    キーワード : 行動経済学、プロスペクト理論、双曲割引、社会的選好、量子確率、リーマン幾何学、神経経済学、量子情報科学
  • 修士論文・特定課題指導特殊演習
    開講年度 : 2019年
    課程区分 : 修士課程
    開講学部 : 文学研究科
  • 行動実験調査法特別演習
    開講年度 : 2019年
    課程区分 : 修士課程
    開講学部 : 文学院
    キーワード : 行動経済学、神経経済学、量子情報科学
  • 修士論文・特定課題指導特殊演習
    開講年度 : 2019年
    課程区分 : 修士課程
    開講学部 : 文学院
  • 行動実験調査法特別演習
    開講年度 : 2019年
    課程区分 : 修士課程
    開講学部 : 文学院
    キーワード : 行動経済学、プロスペクト理論、双曲割引、社会的選好、量子確率、リーマン幾何学、神経経済学、量子情報科学
  • 社会・制度モジュール特殊科目B
    開講年度 : 2019年
    課程区分 : 学士課程
    開講学部 : 現代日本学プログラム課程
    キーワード : 行動科学、社会心理学、進化、文化、適応、比較認知科学
  • 行動システム科学概論
    開講年度 : 2019年
    課程区分 : 学士課程
    開講学部 : 文学部
    キーワード : 行動科学、社会心理学、進化、文化、適応、比較認知科学
  • 社会の認識
    開講年度 : 2019年
    課程区分 : 学士課程
    開講学部 : 全学教育
    キーワード : 行動経済学、神経経済学、量子情報科学、意思決定会計
  • 社会・制度モジュール特殊科目B
    開講年度 : 2019年
    課程区分 : 学士課程
    開講学部 : 現代日本学プログラム課程
    キーワード : 行動経済学、心理会計、社会物理、統計力学、ネットワーク科学
  • 英語演習
    開講年度 : 2019年
    課程区分 : 学士課程
    開講学部 : 全学教育
    キーワード : 行動経済学、神経経済学、量子意思決定理論や量子社会科学、意思決定の行動生物物理学
  • 行動科学演習
    開講年度 : 2019年
    課程区分 : 学士課程
    開講学部 : 文学部
    キーワード : 行動経済学、心理会計、社会物理、統計力学、ネットワーク科学
  • 行動科学特殊演習
    開講年度 : 2019年
    課程区分 : 学士課程
    開講学部 : 文学部
    キーワード : 行動経済学、神経経済学、量子情報科学
  • 行動科学特殊演習
    開講年度 : 2019年
    課程区分 : 学士課程
    開講学部 : 文学部
    キーワード : 行動経済学、神経経済学、量子情報科学、行動ゲーム理論、プロスペクト理論、双曲割引、ホジキン・ハクスレー方程式、ヒルベルト空間
  • 行動科学実験実習
    開講年度 : 2019年
    課程区分 : 学士課程
    開講学部 : 文学部
    キーワード : 行動科学、社会心理学、進化、文化、適応

大学運営

委員歴

  • 2017年08月 - 現在   Journal of Addiction & Recovery   EDITORIAL BOARD
  • 2016年04月 - 現在   横幹連合   基幹役員
  • 2016年 - 現在   International Journal of Applied and Experimental Mathematics   Editorial board member
  • 2014年 - 現在   Adaptive Human Behavior and Physiology (Springer)   Editorial board member
  • 2011年03月 - 現在   行動経済学会   理事
  • - 現在   北海道大学 脳科学研究教育センター   基幹教員
  • - 現在   Journal of Behavioral Economics and Finance   編集委員
  • - 現在   人間行動進化学会   編集委員
  • - 現在   新潟県立大学 実証社会科学研究センター   運営委員
  • - 現在   薬物アルコール学会   評議員
  • 2017年09月 - 2018年09月   Frontiers in Applied Mathematics and Analysis   Topic Editor

社会貢献活動

  • 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
    役割 : 講師


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