Abstract
This study examined conditional reasoning with premises referring to associations between professions and traits that were either stereotypical (“Accountants like mathematics”) or counter-stereotypical (“Nurses like mathematics”). In the first study, participants were asked to rate the degree of certainty of MP and AC inferences based on an individual's profession (“John is an accountant”) or based on an individual trait (“John likes mathematics”), under pragmatic instructions or under strong logical instructions, using a context that required them to put themselves in the position of a fictitious actor. Results showed that both forms of inference were rated as more certain with stereotypical premises than with counter-stereotypical premises and that logical instructions increased the overall strength of inferences without reducing the difference between the two forms of premise. The second study presented both stereotypical premises and inferences with believable and unbelievable conclusions, with no additional context. Participants were given inferences under pragmatic instructions followed by logical instructions, or only under logical instructions. Results show that ratings for both MP and AC inferences were higher for stereotypical than counter-stereotypical items, with a similar difference for inferences with belief-consistent and belief-inconsistent conclusions. Logical instructions clearly reduce the influence of premise type, on both types of problems. Receiving pragmatic instructions initially reduced overall levels of normative responding for stereotypical, but not for classical belief-bias inferences. Individual differences in responding indicate that the debiasing effect of logical instructions depends on initial level of bias shown under pragmatic instructions. The results are interpreted as supporting dual-process theories of reasoning.