Practical versus pragmatic: enlarging the selection task, extending reasoning

In the selection task, individuals generally do not follow the deductive rules of standard logic. In the present research, a new abstract selection task was designed by extending the range of cards that the participants face (inspired by Manktelow, Sutherland and Over, 1995). It was used in two experiments to test predictions about the matching bias and the probabilistic approach of reasoning. By multiplying the number of cards, we showed a reduction of the pq response, indicating that the matching bias may partly be due to practical features of the task (experiment 1). Surprisingly, half of the participants unsystematically turned over specific cards in some categories. The post hoc justifications allowed us to distinguish several possible interpretations of the task, and differing strategies, (either deductive or inductive) in a bid to uncover contradictions. The result was replicated with a short-time procedure. It also showed a progression of the logical p not-q response (experiment 2). We thus propose that a distinction be made between a pragmatic and a practical component of the matching bias. The features of the task also define a range of deductive and inductive strategies to solve the problem.

, 2016