Illusory inferences from a disjunction of conditionals: a new mental models account.

(Johnson-Laird, P.N., & Savary, F. (1999, Illusory inferences: a novel class of erroneous deductions. Cognition, 71, 191-229.) have recently presented a mental models account, based on the so-called principle of truth, for the occurrence of inferences that are compelling but invalid. This article presents an alternative account of the illusory inferences resulting from a disjunction of conditionals. In accordance with our modified theory of mental models of the conditional, we show that the way individuals represent conditionals leads them to misinterpret the locus of the disjunction and prevents them from drawing conclusions from a false conditional, thus accounting for the compelling character of the illusory inference.

How can mental models theory account for content effects in conditional reasoning? A developmental perspective.

This article proposes a modification to Johnson-Laird's mental models theory applied to the interpretation of conditional statement of the form 'if ... then'. The model suggests that this interpretation is based on the construction of mental models supplied by establishing a correspondence between the semantic spaces associated with the antecedent and consequent of the statements. The construction of the models and the interpretation of the statements would depend on the nature of the semantic spaces involved, the interpretative context and the subject's knowledge and processing capacity. Three experiments show that the interpretation of conditional rules depends, for example, on whether or not the conditional rule possess binary terms (e.g. boy/girl). The developmental approach makes it possible to reveal phenomena which tend to remain hidden in studies of adult functioning. We show that the model accounts for a number of the reasoning biases described in the literature as well as for the interpretation of various conditional forms which do not have a truth-functional meaning.