Conditional reasoning is one of the key components of logical reasoning. Studies examining the way that children and adults make conditional inferences have shown that while there are some clear developmental patterns, there is also a great deal of variation in performance due to factors such as problem content. Such variation is difficult to model without an explicit process model. In the following we propose a variant of mental model theory that can explain much of the empirical data. This model (...) suggests that the development of conditional reasoning can be explained, at least partly, by such factors as the capacity of working memory, the range of knowledge available to a reasoner and his/her ability to access this knowledge on-line. (shrink)

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)

Four experiments examined the strategies that individuals develop in sentential reasoning. They led to the discovery of five different strategies. According to the theory proposed in the paper, each of the strategies depends on component tactics, which all normal adults possess, and which are based on mental models. Reasoners vary their use of tactics in ways that have no deterministic account. This variation leads different individuals to assemble different strategies, which include the construction of incremental diagrams corresponding to mental models, (...) and the pursuit of the consequences of a single model step by step. Moreover, the difficulty of a problem (i.e., the number of mental models required by the premises) predisposes reasoners towards certain strategies. Likewise, the sentential connectives in the premises also bias reasoners towards certain strategies, e.g., conditional premises tend to elicit reasoning step by step whereas disjunctive premises tend to elicit incremental diagrams. (shrink)

Inferences about spatial, temporal, and other relations are ubiquitous. This article presents a novel model-based theory of such reasoning. The theory depends on 5 principles. The structure of mental models is iconic as far as possible. The logical consequences of relations emerge from models constructed from the meanings of the relations and from knowledge. Individuals tend to construct only a single, typical model. They spontaneously develop their own strategies for relational reasoning. Regardless of strategy, the difficulty of an inference depends (...) on the process of integration of the information from separate premises, the number of entities that have to be integrated to form a model, and the depth of the relation. The article describes computer implementations of the theory and presents experimental results corroborating its main principle. (shrink)

The present paper focuses on the heuristic selection process preceding the actual transitive reasoning process. A part of the difficulty of transitive reasoning lies in the selection of the relevant problem aspects. Two experiments are presented using the paradigm introduced by Markovits, Dumas, and Malfait (1995), in which children were asked to make “higher than” inferences about arrays of coloured blocks. In order to discriminate between genuine transitive inference and a simple strategy of relative position, Markovits et al. interspersed white (...) blocks with the coloured blocks, such that the relative position strategy leads to erroneous responses. However, we argue that the white blocks cause confusion due to their ambiguity, which interferes with the heuristic selection process. Two methodological adaptations were introduced, which are hypothesised to facilitate the selection process and improve transitive reasoning: (1) the white blocks were replaced by coloured blocks, and (2) a less abstract context was added to the experimental design. The colour manipulation leads to a clear increase in the use of a transitive strategy by 9-year-old children; 8-year-old children mainly used the relative position strategy. When adding a context story, 9-year-old children used the transitive strategy regardless of the colour of the interspersed blocks. The overall performance of 8-year-olds improved slightly. These results are interpreted as support for a dual-process model of transitive reasoning. (shrink)