PROBLEMA recent review of the literature on the estimation of time(13) points out the dearth of data on the motivational aspects of time estimation, although with the paucity of cues available for this kind of judgment, motivational variables should be particularly relevant ('). The present study is concerned with the effects of anxiety and impulse control on the estimation of time.Previous investigators ( 3 -8 ) found that stress tends to increase S's estimation of the duration of "chronological" time. Rosenzweig and Koht ( 6 ) suggest that this is due to some kind of wishful-thinking mechanism, as if S wished that more time had elapsed and the stressful situation was over. An alternate explanation, based on a learning theory approach to stress and 12) is that time estimation under stress presents a much more complex stimulus situation, producing in S a greater number of response tendencies. This increase in associations and response tendencies may thus, assuming that the experience of duration is a function of the number of experienced stimuli (5), be responsible for the finding that stress increases the perceived duration of "chronological" time.In order to test this alternate explanation the present study investigated the relationship between S's level of general anxiety and the estimation of time under normal conditions. In the absence of specific stress, the wishful-thinking hypothesis is no longer relevant.A second objective of this study was to determine the relationship between impulse control or inhibition and the estimation of duration. In a number of studies ( 8 , 9, lo), it was found that time estimations, if obtained according to the production method") in which S is required to delineate certain periods of time, are good indices of a person's impulse control capacity. In these time estimation tasks, the impulsive Ss produce shorter periods of time. It is not clear, however, from these studies whether impulsivity actually influences S's perception of duration or only his tendency to accelerate the response by which he indicates that a specified period of time has elapsed. This ambiguity was resolved in the present study by asking S to estimate certain periods of already elapsed time rather than to delineate these time units.Spivack et al. (lo) have reported significant positive correlations between intelligence and time estimations which were obtained by the production method. But since this kind of task apparently measures 8's estimation of duration as well as his impulse control capacity(** lo), it is not clear whether intelligence is merely related to impulse control or also to the estimation of duration. The present study will investigate the relationship between intelligence and the verbal estimation of elapsed time, and if necessary control for impulsivity.
PROCEDUREThe Ss in this study were 36 undergraduate students a t the Bar-Ilan University in Israel. Each S was presented with the following time intervals, 20,5,20, and 5 secs., the beginning and end of each of which was marked by the cli...