Social memory, social stress, and economic behaviors

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 prisonerfs 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 hormonefs action on social cognition- related brain regions.neuroeconomics, hormone, trust, game theory, social cognition, stress, social memory

A neuroeconomic theory of rational addiction and\ud nonlinear time-perception.

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

Neuroeconomics of suicide.

Suicidal behavior is a leading cause of injury and death worldwide. Suicide has been associated with psychiatric illnesses such as depression and schizophrenia, as well as economic uncertainty, and social/cultural factors. This study proposes a neuroeconomic framework of suicide. Neuroeconomic parameters (e.g., risk-attitude, probability weighting, time discounting in intertemporal choice, and loss aversion) are predicted to be related to suicidal behavior. Neurobiological and neuroendocrinological substrates such as serotonin, dopamine, cortisol (HPA axis), nitric oxide, serum cholesterol, epinephrine, norepinephrine, gonadal hormones (e.g., estradiol and progesterone), dehydroepiandrosterone (DHEA) in brain regions such as the orbitofrontal/dorsolateral prefrontal cortex and limbic regions (e.g., the amygdala) may supposedly be related to the neuroeconomic parameters modulating the risk of suicide. The present framework puts foundations for ―molecular neuroeconomics‖ of decision-making processes underlying suicidal behavior

Cultural Neuroeconomics of Intertemporal Choice

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\ud 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 briefly outlined and discussed

A hyperbolic decay of subjective probability of obtaining delayed rewards

<p>Abstract</p> <p>Background</p> <p>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.</p> <p>Methods</p> <p>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.</p> <p>Results</p> <p>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.</p> <p>Conclusion</p> <p>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.</p