The solution of an inferential problem as a function of stimulus materials

Stimulus materials were varied in three ways to assess the effect on performance of problems involving implicational rules. The three factors were natural versus arbitrary relationship between the terms of the problem, concrete versus abstract problem material and order of the presentation of the terms in the rules. The natural relationship condition facilitated performance compared with the arbitrary relationship condition. This difference was explained in terms of differential cognitive load. A significant interaction between materials and order factors was attributed to semantic differences in the rules.