Estimation of time: Effects of locus of control, mental arithmetic and length of target interval

The estimation of time is often regarded as a cognitive process. Several theories have been suggested to explain the relationship between the information processing load and the estimated length of the target interval. These models, however, mainly explain the process of judging intervals during which attention is directed towards the passage of time. Also, more importantly, they often do not include variables measuring individual differences, which could account for some of the contradictory results obtained. According to the findings in this study, when a demanding task is performed, all subjects do not become less accurate as predicted by the existing models. The results of the present study show instead clear differences in the estimations between individuals labeled as having an internal or external locus of control. When performing mental arithmetic, these two groups are affected differently in their estimations of intervals of varying length, which might be explained in terms of the alleged difference in information processing capacity described in other studies.