Temporal generalizations in humans: Three further studies.

Three experiments investigated human performance on variants of the temporal generalization procedure developed by Wearden (1992) from an experiment with animals by Church and Gibbon (1982). All experiments used short tone durations as stimuli to be judged, and chronometric counting was not spontaneously used by subjects. Experiment 1 studied the effects of extended exposure to a temporal generalization procedure, with a 400 ms standard duration. With increasing exposure, subjects' tendency to produce judgemental asymmetries (i.e. confusing a 500 ms stimulus more with the standard than a 300 ms one, a standard result in temporal generalization with human subjects) decreased, and this was modelled theoretically by assuming that subjects came to adopt stricter response criteria for durations longer than the standard than those which were shorter. Experiment 2 used standard durations which were at the end of a stimulus set ranging from 200 to 800 ms. Orderly generalization functions were obtained in these cases, and data were well-fitted by a standard model of temporal generalization. Experiment 3 used an 'episodic' variant of temporal generalization, involving the comparison of the durations of 2 stimuli present on a trial. Once again judgemental asymmetries were found, but standard models of temporal generalization failed to fit data from some cases. Overall, both experimental effects and theoretical treatments from temporal generalization studies were robust in the face of procedural variations.