Four experiments assessed the relative involvement of different working memory components in two types of reasoning tasks: propositional and spatial reasoning. Using the secondary-task methodology, visual, central-executive, and phonological loads were realised. Although the involvement of visuospatial resources in propositional reasoning has traditionally been considered to be small, an overall analysis of the present data suggests an alternative account. A theoretical analysis of the pattern of results in terms of Evans' (1984, 1989) twostage theory of reasoning is proposed and tested (...) in Experiments 3 and 4, in which direct evidence for the alternative account was obtained: significant disruption of propositional reasoning by a concurrent spatial load. (shrink)

We resolve the two problems that Hardman raises. The first problem arises from a misunderstanding: the crucial distinction is between one-model and multiple-model problems. The second problem illuminates a deeper principle: conclusions depend on the procedures for interpreting models. We describe an algorithm that obviates the problem and empirical work that reveals a new view of syllogistic reasoning.