The omnidirectional aspect of the auditory channel makes it the method of choice for many situations requiring operator warnings, including situations requiring the operator of a motor vehicle to be warned of an impending collision. Ideally, an auditory warning system minimizes localization errors and response times. This article reviews the literature that bears on these concerns. Sound localization has been studied extensively. Although much is known about factors that affect errors, little is known about factors that influence response time. Three experiments were performed in an attempt to identify the separate influence of each of several different factors. All trials used a single broadband noise signal emanating from one of a subset of six loudspeakers equally spaced around the participant in the azimuthal plane. Both the site of the subset and the balance of relative probabilities from speaker to speaker were altered to evaluate the relationship between information content and the dependent variable, choice reaction time. Choice reaction time was found to be related to the information content of the sound stimulus in all cases. It was also found to be related to the presence of pairs of speakers that were symmetrically opposed in front of and behind the participant. Models of choice reaction time in a sound localization task have clear implications for practice. For example, they suggest that multiple auditory collision warnings may endanger drivers.
Abstract