This paper was presented at the THIRD INTERNATIONAL CONFERENCE ON THINKING.
British Psychological Society. Cognitive Psychology Section. University
College London. August, 1996"This experiment explores the effect of the scenario’s availability,
instruction (true/false vs. violation) and presentation order on performance
in different versions of Wason’s selection task. Each subject was given
three problems corresponding to the content of the three different rules
(abstract content, thematic-permission and thematic-norm). The main
analyses are presented in terms of matching and logical index (Pollard and
Evans, 1987).
The matching and logical index were influenced by the contents of
the rules. Also there exist an interaction between instructions and content in
the logical index. In the abstract version, as in the thematic-obligation, the
logical indices are superior on the individuals that receive violation
instructions, whilst that in the thematic-permission the best performance
was registered with true/false instructions. The results are not consistent
with syntactic theories of human reasoning, and are discussed in terms of
pragmatic and semantic theories of human reasoning
