Proceedings of the Annual Meeting of the Cognitive Science Society

This study explored the effects c: a goal and subject's knowledge in similsirity judgements. W e hypothesized that the process of computing similarity consist of two phases: the processes of explanation and feature comparison. W h e n a goal is salient and the knowledge required to achieve it is available, people compute similarity by explaining the goal in terms of a given state by using domain knowledge. Thus, in this case, rated similarity should be a function of the distance between the goal and the state. W h en the explanation fails, the judgements should instead to be based on the feature comparison. Expert, novice, and naive subjects were asked to solve the Tower of Hanoi puzzle. The subjects were required to judge the similarity between the goal and various states of the puzzle. The results showed that their judgements differed, depending on their expertise. While experts' ratings were best characterized by the number of operators necessary to transform a given state to the goal, those of naive subjects were completely based on the number of shared features. The second experiment revealed that the experts' judgements of similarity are not be due to learned contiguity through practice.