Collaborative Research: Investigating the Genetic Basis of Economic Behavior

合作、道德惩罚和其他形式的不完全理性经常成为人类行为的特征，这与经典的理性假设所得出的预测相矛盾。然而，同样的经济学研究表明，人类并不完全自私，但这些研究也表明，实验性游戏的玩法存在很大差异。相当一部分研究对象的行为完全是自私自利的，从标准微观经济学理论中得出的概念框架可以很好地解释这种行为。在另一个极端，类似的少数受试者表现出一致的强烈利他主义倾向。大多数人都处于行为连续体的这两个极端之间。如何解释这种差异？对于社会科学来说，这是一个关键问题--也许是关键问题。这个项目使用了一项基于双胞胎的研究设计，来评估遗传倾向、共同的环境和独特的经历在解释基本社交中广泛观察到的行为差异方面的相对贡献。双胞胎设计利用了两种不同类型的双胞胎的存在：同卵双胞胎(MZ)和异卵双胞胎(DZ)，他们100%分享他们的遗传物质；以及异卵双胞胎(DZ)，他们分享50%的遗传物质。将MZ双胞胎之间的经济博弈相关性与DZ双胞胎之间的相关性进行比较，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。类似的研究已经使用这些方法来确定，从宗教信仰到政治态度，各种行为和态度的遗传性都高得令人惊讶。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。确定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相关联，将提供令人信服的经验证据，表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，它将提供一个有用的平台，用于从总体上形成更完整和更稳健的人类行为理论。确定亲社会行为的差异至少部分是由遗传学解释的，这为更全面地理解驱动有目的行为的偏好铺平了道路。这个项目可以开始识别驱动有目的的行为的目的的来源，而不是把偏好当作给定的，或者完全是环境力量的产物。

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.