A Two-Stage Model of Conditional Reasoning

Abstract

Conditional reasoning, or reasoning from propositions expressed in the form if P then q, is particularly interesting to investigate because several previous studies have shown people to perform very poorly at this task. The well-known Wason card selection paradigm dramatically reveals the gap between normatively applied (formal) logical rules as opposed to human performance in such reasoning task. Wason(l966) presented his subjects with four cards showing symbols as given in the picture. They were informed that each card had a letter on one side and a number on the other. Then, they were given a rule such as: If a card has a vowel on one side, then it hαg aη even number on the other side.