Time Estimation among Schizophrenics 1

Abstract

Studies of time estimation among schizophrenics have sometimes been difficult to integrate with one another because of differing methodologies and inconsistent definitions. The present study should increase clarity by employing several methods of time estimation within the same study and maintaining a consistent definition of overestimation and underestimation across tasks. 26 schizophrenic and 26 control subjects were given three types of time-estimation tasks. Longer Interval Estimation involved judging, at different points in the interview/testing session, how much time had passed. Verbal Estimation required subjects to judge the length of brief intervals signalled by the examiner. Operative Estimation required subjects to indicate when a specified number of seconds had passed. Schizophrenic subjects were significantly more inaccurate than controls in the Verbal and Operative Estimation tasks. Moreover, with overestimation defined consistently as judging more time to have passed than actually has, both Verbal and Operative Estimation results indicated schizophrenics were significantly more likely to overestimate. These results indicate support for the suggestion that schizophrenics have a disturbed sense of time, with real (clock) time experienced as passing more slowly than is actually the case. Long Interval Estimation produced quite different results, but it was felt that the retrospective and unfocused nature of the time judgments in this task made it a less valid indicator of ability to estimate.