Why we are so good at catching cheaters

Data that appear to exhibit a 'cheater detection' effect on performance in the Wason Selection task are widely interpreted as implying that deontic re asoning is effected by a domain specific, cognitive module. The 'cheater de tection module' is said to offer a clear example of an effect of evolutiona ry selection on human cognitive architecture. This interpretation depends c ritically on assuming that deontic conditionals and their indicative contro ls an identical in structure, hence that the asymmetries in S's performance must be effects of content variables. I argue that this assumption is untr ue and that structural features of deontic conditionals predict the 'cheate r detection' data without assumptions about either the architecture or the history of cognition. According to this analysis, the putative cheater dete ction effect on the Wason task is actually a materials artifact. (C) 2000 P ublished by Elsevier Science B.V. All rights reserved.