TEMPORAL PROCESSING, RANGE EFFECT AND WEBER FRACTION

  • Simon Grondin
  • Nicolas Bisson
  • Caroline Gagnon

Abstract

The aim of this study was to measure the impact on threshold estimates, for temporaldiscrimination, of the range of comparison intervals on a psychometric function. Theexperiment included two standard interval durations (.2 and 1 s) and compared a conditionwhere all (8) comparison intervals were randomized within blocks with a condition whereonly pairs of intervals varied within blocks. The results revealed that the mode of presentation(totally randomized vs. only pairs of intervals within blocks) did not have an effect, whereasthe range of comparison intervals did have one, although the effect depended on the standardintervals. With brief intervals (.2 s), using a narrower range of comparison intervals led to asmaller mean difference threshold. The results show that the parameters selected for drawingpsychometric functions determine whether the Weber fraction remains constant between .2and 1 s.
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