Visual-auditory differences in duration discrimination depend on modality-specific, sensory-automatic temporal processing: Converging evidence for the validity of the Sensory-Automatic Timing Hypothesis

The Sensory-Automatic Timing Hypothesis assumes visual-auditory differences in duration discrimination to originate from sensory-automatic temporal processing. Although temporal discrimination of extremely brief intervals in the range of tens-of-milliseconds is predicted to depend mainly on modality-specific, sensory-automatic temporal processing, duration discrimination of longer intervals is predicted to require more and more amodal, higher order cognitive resources and decreasing input from the sensory-automatic timing system with increasing interval duration. In two duration discrimination experiments with sensory modality as a within- and a between-subjects variable, respectively, we tested two decisive predictions derived from the Sensory-Automatic Timing Hypothesis: (1) visual-auditory differences in duration discrimination were expected to be larger for brief intervals in the tens-of-milliseconds range than for longer ones, and (2) visual-auditory differences in duration discrimination of longer intervals should disappear when statistically controlled for modality-specific input from the sensory-automatic timing system. In both experiments, visual-auditory differences in duration discrimination were larger for the brief than for the longer intervals. Furthermore, visual-auditory differences observed with longer intervals disappeared when statistically controlled for modality-specific input from the sensory-automatic timing system. Thus, our findings clearly confirmed the validity of the Sensory-Automatic Timing Hypothesis.