Max Planck Institute for Human Development, Berlin, Germany
Undoubtedly one of the most important studies in evolutionary cognitive psychology is Cosmides' (1989) analysis of content effects on the Wason selection task in terms of adaptive cheater detection. However, in her landmark paper, Cosmides ventured beyond the confines of the selection task to argue for a bold new synthesis of evolutionary biology and cognitive psychology using Marr's (1982) concept of a computational theory as the bridge between these two disciplines. Following Marr's lead, Cosmides argued that cognitive psychology could not make progress unless it was informed by task analyses of the problems the mind was designed to solve. These task analyses would ultimately be supplied by evolutionary theory, which specializes in the study of natural design. Social Contract Theory, Cosmides' specific account of content effects on the Wason selection task, was merely one illustrative part of a larger programme, evolutionary psychology. Unfortunately, the double message of Cosmides' (1989) paper has generated a considerable amount of confusion as some appear to have confused Social Contract Theory as a general theory of reasoning whereas the true scope of the theory is much narrower. In this chapter I hope to dispel some of the confusion surrounding Social Contract Theory and, in the process, clarify where some of the difficulties facing the theory lie and where they do not.
Cosmides (1989) illustrated the benefits offered by an evolutionary perspective by making an example of the then puzzling literature on the Wason selection task. The Wason selection task was originally developed by Peter Wason (1968) as a test of people's ability to logically falsify a hypothesis. By then, the selection task had already generated a large literature, for while it is