Ulric B. and Evelyn L. Bray Seminar

The study of decision making lies at the heart of economics and much of the social sciences. We report the results of several studies to seek a deeper understanding of economic decision making at the level of molecular genetics. Specific findings under social decision making include altruistic giving in a Dictator Game being linked to the arginine vasopressin 1a receptor (AVPR1a) and fairness preferences in the Ultimatum Game being jointly associated with gene (DRD4) x environment (season-of-birth) and that gender difference in fairness preference is further linked to sex-hormone genes. For individual decision making, we have developed a neurochemistry-based model of a reference-dependent valuation function together with a reference-dependent saliency function that links neurochemical properties at the gene level to observable risky choice. This was tested in two studies. One links attitude towards even-chance risks over gains and over losses to a dopamine polymorphism DAT1 and a serotonergic polymorphism STin2 and another links attitude towards longshot risks to the monoamine oxidase A (MAOA) gene. We further carried out a genome-wide-association (GWA) study of 1800 Han Chinese subjects from Singapore (~1100) and Beijing (~700) who participated in incentivized laboratory experiments on individual and social decision making and were inventoried for personality traits, facets of social cognition, and religious-spiritual orientation, and identified specific genes at GWA significance (p < 5 x 10-8) for some decision making phenotypes.