American Political Science Review


“Machiavellian” Intelligence as a Basis for the Evolution of Cooperative Dispositions

a1 University of Oregon
a2 Waseda University
a3 University of Illinois, Springfield
a4 University of Melbourne


How to promote cooperative behavior is classically solved by incentives that lead self-interested individuals in socially desirable directions, but by now well-established laboratory results show that people often do act cooperatively, even at significant cost to themselves. These results suggest that cooperative dispositions might be an evolved part of human nature. Yet such dispositions appear inconsistent with the “Machiavellian intelligence” paradigm, which develops the idea that our brains have evolved, in substantial part, for capturing adaptive advantage from within-group competition. We use simulation to address the evolutionary relationship between basic Machiavellian capacities and cooperative dispositions. Results show that selection on such capacities can (1) permit the spread of cooperative dispositions even in cooperation-unfriendly worlds and (2) support transitions to populations with high mean cooperative dispositions. We distinguish between “rationality in action” and “rationality in design”—the adaptive fit between a design attribute of an animal and its environment. The combination of well-developed Machiavellian intelligence, modest mistrust, and high cooperative dispositions appears to be a rational design for the brains of highly political animals such as ourselves.

c1 Professor, Department of Political Science, 936 PLC Hall, 1415 Kincaid Street, University of Oregon, Eugene, OR 97403-1284 (
c2 Professor, International College, Waseda University, Tokyo, Japan (
c3 Instructor, Political Science Department, University of Oregon, Eugene, OR 97403. (
c4 Assistant Professor, Political Studies Program, University of Illinois, Springfield, IL 62703 (
c5 Principal Research Fellow, ORYGEN Research Centre, and Associate Professor, Department of Psychology, University of Melbourne, Melbourne, Australia (