Temporal perception of acoustically presented time series
Data from three experiments on serial perception of temporal intervals are reported. Sequences of short acoustic signals (â€˜pipsâ€™) separated by periods of silence were presented to the observers (N = 24, 16, 12). The inter-pip intervals were generated to form geometric or alternating se- ries, while the modulus 1+Î´ of the stimulus series and the base duration T0 (in the range from 1.1 to 6 seconds) were varied as independent parameters. The observers had to judge whether the pips sequences were accelerating, decelerating, or uniform, or to distinguish regular from irregular sequences. â€˜Intervals of subjective uniformityâ€™ (ISU) were obtained by fitting Gaus- sian psychometric functions to individual subjectsâ€™ responses. Progression towards longer base durations (T0 = 4.4 or 6 seconds) shifts the ISUs towards negative Î´ s, i. e., accelerating series. This finding is compatible with the phenomenon of â€˜subjective shorteningâ€™ of past temporal intervals, accounted for by the lossy integration model of internal time representation.