Proceedings of the Annual Meeting of the Cognitive Science Society

The paper describes a theory of temporal reasoning and its implementation in a computer program. The theory postulates that individuals construct mental models, and it predicts that inferences that call for only one model to be constructed, such as: a happens before b. b happens before c. d happens while b. e happens while c. What is the temporal relation between d and e? will be easier than those that call for multiple models, such as a problem identical to the previous one except for its first premise: a happens before c. Experiment 1 showed that subjects were faster and more accurate with one-model problems than with multiple-model problems. They look more time to read a premise leading to multiple models than the corresponding premise in a one-model problem. Experiment 2 showed that if the question came first and was presented with all the premises, then subjects can ignore an irrelevant premise. As predicted, the difference between one-model and multiple-model problems with valid conclusions then disappeared. Experiment 3 showed that the size of a model, i.e., the number of events in it, and the distance apart of the critical events, also affected performance.