Collaborative Research: Investigating the Genetic Basis of Economic Behavior

合作、道德惩罚和其他形式的不完美理性经常是人类行为的特征，这与从经典理性假设中得出的预测相矛盾。然而，同样的经济学研究表明，人类并非完全自利，也证明了实验游戏玩法的广泛差异。少数研究对象的行为是非常自利的，可以用标准微观经济学理论的概念框架很好地解释。在另一个极端，类似的少数受试者表现出一贯的强烈利他主义倾向。大多数人都处于这两个行为连续体的两端之间。如何解释这种差异呢？这是一个关键问题——也许是社会科学的关键问题。答案有望阐明偏好的来源，从而阐明人们为什么会做他们所做的事情。本项目采用基于双胞胎的研究设计来评估遗传易感性、共同环境和独特经历在解释基本社会互动中广泛观察到的行为变化方面的相对贡献。双胞胎设计利用了两种不同类型的双胞胎：同卵双胞胎（MZ），他们共享100%的遗传物质；和异卵双胞胎（DZ），他们共享50%的遗传物质。比较MZ双胞胎和DZ双胞胎在经济博弈中的相关性，提供了一种将观察到的行为差异划分为遗传、共同环境（即双胞胎共同的环境部分）和独特环境成分的方法。类似的研究使用这些方法来确定，从宗教信仰到政治态度，各种各样的行为和态度都有惊人的高遗传水平。然而，到目前为止，还没有大规模的研究估计亲社会行为的遗传基础。建立亲社会行为具有遗传成分，并将特定基因与亲社会行为特征联系起来，将提供令人信服的经验证据，证明经济行为不仅仅是环境或制度激励的产物。这不仅有助于解释为什么观察到的行为并不总是符合主流经济理论，更重要的是，它将为制定更完整、更有力的人类行为理论提供一个有用的平台。亲社会行为的变化至少部分可以用遗传学来解释，这为更全面地理解驱动有目的行为的偏好铺平了道路。这个项目可以开始确定驱动目的性行为的目的的来源，而不是将偏好视为给定的，或完全作为环境力量的产物。

Cooperation, moralistic punishment and other forms of imperfect rationality frequently characterize human behavior, in contradiction to the predictions derived from classic assumptions of rationality. Yet the same economic studies that show that humans are not entirely self-interested also demonstrate wide variation in experimental game play. The behavior of a significant minority of research subjects is quite self-interested and is explained well by conceptual frameworks drawn from standard microeconomic theory. On the other extreme, a similar minority of subjects exhibit consistent strongly altruistic tendencies. Most people are spread between these two ends of the behavioral continuum. What explains this variation? This is a key question--perhaps the key question--for the social sciences. The answer promises to illuminate the source of preferences and so shed light on why people do what they do.This project uses a twin-based research design to assess the relative contributions of genetic predisposition, shared environment, and unique experiences in accounting for the broadly observed behavioral variation in fundamental social interaction. The twin design takes advantage of the existence of two distinct types of twin pairs: Monozygotic (MZ) twins, who share 100 percent of their genetic material; and dizygotic (DZ) twins, who share 50 percent of their genetic material. Comparing the correlation in economic game play between MZ twin pairs with the correlation between DZ twin pairs provides a means to partition the observed variance in behaviors into genetic, common environmental (i.e., that part of the environment common to both twins), and unique environmental components. Similar studies have used these methods to establish that there are surprisingly high levels of heritability for a wide range of behaviors and attitudes, ranging from religiosity to political attitudes. Thus far, however, no large scale study has estimated the genetic basis of pro-social behaviors.Establishing that pro-social behavior has a heritable component and correlating specific genes with pro-social behavioral traits would provide convincing empirical evidence that economic behavior is not just a product of environmental or institutional incentives. This would not only help to explain why observed behavior does not always comport with mainstream economic theory, but more importantly it would provide a useful platform for formulating more complete and robust theories of human behavior generally. Establishing that variation in pro-social behaviors is explained at least partially by genetics paves the way for a more complete understanding of the preferences that drive purposive behavior. Rather than taking preferences as given, or as wholly products of environmental forces, this project could begin to identify the source of the purposes that drive purposive behavior.