Judgment of time as a function of serial position and stress.

Abstract

The effects of the serial position of judgment and mild stress induced upon judgment of a 15-sec. interval by the production method were explored. An experimental group (N=20) received shock at the end of certain trials, and a control group (N=20) never received shock. The S was forewarned at the beginning of each time interval of the type of consequences to be received at the end of the interval. Statistically significant serial position gradients for temporal judgments were found in both groups. These gradients were more-or-less linear, and ran from over-estimation in the earlier trials to underestimation in the later trials. The experimental group gave significantly greater overestimation when compared with the control group, but the direction and slope of the serial position gradient was not significantly altered. It is argued that the serial position gradient does not result either from time-order error, or from an improvement in ability to judge time. Greater overestimation of the interval by the experimental group (relative to the control group) is interpreted in terms of an anxious set induced by the expectation of shock.