Echo avoidance in a computational model of the precedence effect

The precedence effect, though a topic of continuous theoretical interest in hearing research, so far cannot be predicted explicitly by a model. Zurek (1987) reviewed the precedence effect and gave a general structure for the model of the precedence effect. However, it is still not clear how the inhibition of localization is generated. This paper proposes a computational echo-avoidance model by assuming that the precedence effect is caused by the inhibition of sound localization which depends on the estimated sound-to-echo ratio. We assume there is a neural echo-estimation mechanism in the human auditory system. It is found that a temporal pattern of aftereffect with delay and decay features, which is adopted from the previous psychological tests on the increase of the perceptual threshold of interaural time difference following a preceding impulsive sound, can be used for echo estimation. The time variance of the precedence effect is briefly discussed. The results of psychological experiments, e.g. equal-level and unequal-level paired click tests, Haas's tests and Franssen's tests, are interpreted consistently This model can also give criteria for an available onset and an explanation of why the precedence effect occurs in transient onsets. (C) 1999 Elsevier Science B.V. All rights reserved.