Modeling homo sociologicus : social influence and interdependent behavior in economics

Economics has been criticized by other disciplines, and by some prominent economists themselves, for many of its methodological choices, in particular the specific assumptions in models. Some of these critiques have been appropriated by economists, giving rise to new sub-fields of economics. Critics from the field of history and sociology have long pointed out that the economic models of markets are not historically and institutionally embodied, as the real markets are. Various strands of institutional economics arose from such criticism. Claims by ecologists that natural capital is not completely substitutable with other forms of capital fostered the development of ecological economics. Likewise, criticism from psychologists that decision makers are irrational or boundedly rational foster the development of behavioral economics. This chapter concerns another example of persistent criticism, namely the assumption in economics that \emph{homo economicus} is an asocial animal, which does not hold on evolutionary, psychological or sociological grounds. How have economists responded to this criticism, and how successful have they been? To focus the discussion, I will review four strategies of model modification that aim to address the sociality of human behavior and interactions in the framework of rational choice. In particular, I will focus on modifications of game theory, which is the main analytical tool economists use to model interdependent choices. The perspective I adopt here reflects mainstream approaches to economic modeling, and I do not discuss more radical proposals to use entirely new frameworks such as complexity theory or network theory \citep[see e.g.][]{mason2007a}. This focus on the mainstream approaches is motivated as a useful way to highlight core characteristics of economic explanations of sociality. The review of four major approaches to modeling social influence in economics will indicate different interpretations of sociality, followed by a suggestion that the non-reductive and constructive interpretation brings economics closer to sociology and away from psychology and biology.Peer reviewe