Integration of Auditory and Tactile Information in Time-to-Contact Estimation

This study investigated the integration of auditory and tactile information in time-to-contact (TTC) estimation for objects moving with constant velocity (Experiment 1) and constant acceleration (Experiment 2). Participants estimated TTC using a prediction-motion task under auditory, tactile, and audio-tactile conditions to determine whether people can use vibrotactile stimuli to judge TTC and whether concurrent cues improve judgments compared to single modalities. Analyses of absolute constant error revealed a sensory modality effect in Experiment 2, where audio-tactile stimuli produced lower error than tactile alone, but not in Experiment 1. Variable error showed greater audio-tactile precision over tactile-only stimuli across both experiments, though audio-tactile performance never differed from auditory-only cues. These findings are consistent with the revised tau theory, in which people combine first-order information from several sources to make TTC estimations.