Rhyme or Reason: An investigation into the physiological underpinnings of the Wason selection task

University of Minnesota Ph.D. dissertation. August 2008. Major: Psychology. Advisor: Charles R. Fletcher. 1 computer file (PDF); viii, 196 pages.The Wason Selection task is a deceptively simple task that can take on many different forms. When its form is abstract, participants scratch at their heads and fail to grasp the underlying logic. However, changing its form to a story, or a familiar situation almost instantaneously elicits the correct response. The explanation for this thematic effect has led to a substantial amount of consternation within the field and two opposing theories have pushed their way to the forefront. Social Contract Theory argues that humans have evolved a specialized cheater detection mechanism that enables us to reason about social interactions and cost-benefit deals. When the thematic form of the task is in the form of a social contract, this reasoning mechanism is chosen pre-emptively as the ‘weapon of choice’ in solving the problem. Relevance theory, on the other hand, argues that the thematic effect is due to mechanisms of discourse comprehension. However, changing the task so that it looks more like a story, triggers the comprehension mechanisms that we have already developed through other social interactions. According to Relevance theory, the Wason Selection task is not a reasoning task at all, and should not be tested as such. Through three experiments, this study develops and tests a new, within-subjects procedure as well as new sets of materials. After ensuring that the new procedure and materials elicit this thematic effect and other common findings, a physiological experiment is conducted. Based on the predictions of Social Contract theory and related physiological work in emotional reasoning (e.g. Bechara, 2002), it was predicted that Wason tasks would elicit greater Galvanic skin responses when compared to matched Comprehension stories. Participants did have a significantly higher galvanic skin response for the Wason tasks, indicating a higher level of anxiety. This finding shows that there is a sort of reasoning beyond discourse comprehension involved in the Wason task. A discussion centered on the implications for future imaging studies and the Wason task as a whole is included