The role of number and familiarity of stimuli in the perception of brief temporal intervals.

The influence of stimulus number and familiarity on judged duration were investigated. The stimuli were slides with different numbers of stimulus elements of a familiar or unfamiliar nature. The task was to reproduce the durations of the slides, each shown for four intervals: 5, 9, 13, and 17 sec. The results show that the number of stimulus elements presented within a given interval affected its perceived duration, although the familiarity of those elements (as defined herein) did not. Finally, the shorter intervals sampled here were overestimated and the longer intervals were underestimated, thereby supporting Vierordt's law.