Temporal perception of acoustically presented time series

  • Jirí Wackermann
  • Jakob Pacer
  • Marc Wittmann

Abstract

Data from three experiments on serial perception of temporal intervals are reported. Sequences of short acoustic signals (‘pips’) 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+δ 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. ‘Intervals of subjective uniformity’ (ISU) were obtained by fitting Gaus- sian psychometric functions to individual subjects’ responses. Progression towards longer base durations (T0 = 4.4 or 6 seconds) shifts the ISUs towards negative δ s, i. e., accelerating series. This finding is compatible with the phenomenon of ‘subjective shortening’ of past temporal intervals, accounted for by the lossy integration model of internal time representation.

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