Auditory and visual temporal sensitivity: evidence for a hierarchical structure of modality-specific and modality-independent levels of temporal information processing.

The present study investigated modality-specific differences in processing of temporal information in the subsecond range. For this purpose, participants performed auditory and visual versions of a rhythm perception and three different duration discrimination tasks to allow for a direct, systematic comparison across both sensory modalities. Our findings clearly indicate higher temporal sensitivity in the auditory than in the visual domain irrespective of type of timing task. To further evaluate whether there is evidence for a common modality-independent timing mechanism or for multiple modality-specific mechanisms, we used structural equation modeling to test three different theoretical models. Neither a single modality-independent timing mechanism, nor two independent modality-specific timing mechanisms fitted the empirical data. Rather, the data are well described by a hierarchical model with modality-specific visual and auditory temporal processing at a first level and a modality-independent processing system at a second level of the hierarchy.