The use of accurate versus heuristic auditory and visual cues for time-to-collision judgments

Abstract

Estimating time-to-collision (TTC) is needed when pedestrians cross a road and a vehicle is approaching. An accurate auditory cue to judge the TTC of a sound source approaching at constant velocity is provided by the ratio of an object’s instantaneous sound intensity to its instantaneous rate of change in sound intensity (auditory τ). However, heuristic-based auditory cues might also be used, as suggested by research in vision. We presented auditory and visual simulations of approaching objects. Auditory and visual TTC cues were decorrelated by slightly shifting auditory TTC against visual TTC. This permitted the estimation of cue weights for auditory cues (e.g., auditory τ, final sound pressure level) and visual cues (e.g., visual τ, final optical size) in three sensory conditions: auditory-only, visual-only, and audiovisual. Results showed that TTC estimates in the auditory-only condition were primarily based on an auditory heuristic cue (final sound pressure level) rather than on auditory τ. In the visual-only condition, visual τ was more important than the heuristic cues. In the audiovisual condition, participants relied more strongly on visual cues than auditory cues. We discuss the need for more refined auditory simulations to gain further insight into the cue weighting in everyday situations.