ABSTRACT
We introduced the Wason selection task in Chapter 3, together with arguments and evidence that subjects choose cards that appear relevant. In particular, the evidence from the inspection time experiments of Evans (1995b and in press) is that subjects focus their attention only on the cards they choose, even when thematic and deontic versions of the task are presented. Because the logical analysis of the selection task requires consequential reasoning about the hidden sides of each card, it is not surprising therefore that behaviour on this task often appears illogical or irrational2. However, as we have repeatedly argued, the tacit processes that underlie relevance typically produce behaviour that is rational!—serving the personal goals of the individual. Our purpose in this chapter is first to argue that subjects’ choices on various forms of the selection task are often rational1, provided that the task is viewed as one of decision making rather than deductive reasoning. Secondly, we will suggest a mechanism by which such rational1 choices come about—via the cueing of relevance that causes subjects to focus on particular mental models. Relevance serves rationality1 because it is closely linked to the current goal that the subject is pursuing.
