Does reasoning occur on the Wason selection task, or are card selections determined purely on the basis of heuristic processes? To answer this question two relevance-based theories of reasoning are compared: (1) the theory of Evans (1984, 1989; Evans & Over, 1996), which takes the heuristic viewpoint, and (2) the theory of Sperber, Cara, and Girotto (1995), which takes the reasoning viewpoint. In three experiments, the effect of removing matching cards from the selection task array is examined. It is argued (...) that the Sperber et al. theory makes clearer predictions about the results of these manipulations, which are confirmed, and that the Evans theory can only accommodate them if it allows the operation of reasoning processes. The results are also discussed in relation to Roth's (1979) account of the selection task, mental models theory, and information gain theory. (shrink)

Mental models theorists have proposed that reasoners tend to focus on what is explicit in their mental models, and that certain debiasing procedures can induce them to direct their attention to other relevant information. For instance, Green and Larking 1995; also Green, 1995a facilitated performance on the Wason selection task by inducing participants to consider counterexamples to the conditional rule. However, these authors acknowledged that one aspect of their data might require some modification to the mental models theory. This research (...) is discussed here, and it is suggested that the results may be better accommodated by mental inference rules theory than by mental models theory. (shrink)

Can the understanding/acceptance principle help us to decide between alternative normative theories? There is little evidence that this principle can successfully be applied; there are no strong normative statements in Stanovich & West's target article. There is also no evidence for success of rational norms when applied to real life decisions.