The mental model theory of spatial reasoning re-examined: the role of relevance in premise order.

The effect of premise order on spatial reasoning was investigated using a paradigm introduced by Byrne & Johnson-Laird in 1989. Three kinds of problems were developed: the first of these was expected to prompt one mental model, whereas the second and third were expected to prompt two mental models. The two-model problems differed from each other by the position (first or last) of a premise which was responsible for an indeterminacy. On the basis of Sperber & Wilson's Relevance theory, published in 1986 and 1995, it was predicted and observed that a two-model problem with the crucial premise in the last position was easier than a two-model problem with the crucial premise in the first position. Moreover, it was predicted and observed that the two-model problem with the crucial premise in the last position was as easy as the one-model problem. Implications of these results for the standard mental model theory of spatial reasoning are discussed.