[Forecast ability of the auditory system during perception of gradually or abruptly moving short sound images].

The ability to localize endpoints of sound image trajectories was studied in comparison with stationary sound image positions. Sound images moved either gradually or abruptly to the left or right from the head midline. Different types of sound image movement were simulated by manipulating the interaural time delay. Subjects were asked to estimate the position of the virtual sound source, using the graphic tablet. It was revealed that the perceived endpoints of the moving sound image trajectories, like stationary stimulus positions, depended on the interaural time delay. The perceived endpoints of the moving sound images simulated by stimuli with the final interaural time delay lower than 200 micros were displaced further from the head midline as compared to stationary stimuli of the same interaural time delays. This forward displacement of the perceived position of the moving target can be considered as "representational momentum" and can be explained by mental extrapolation of the dynamic information, which is necessary for successive sensorimotor coordination. For interaural time delays above 400 micros, final positions of gradually and abruptly moving sound sources were closer to the head midline than corresponding stationary sound image position. When comparing the results of both duration conditions, it was shown that in case of longer stimuli the endpoints of gradually moving sound images were lateralized further from the head midline for interaural time delays above 400 micros.