Abstract:

The precedence effect states that the first sound wave arriving at a listener has more influence on the perception of location than later arriving echoes. When a source plus echoes is perceived approximately at the location of the source, the image is said to be ``fused.'' The following set of experiments introduces a new procedure to estimate fusion of clicks. Listeners are presented with a source click plus a single echo click at a variety of delays. Stimuli are rated between a value of ``0'' and ``100,'' with ``0'' indicating a single source and ``100'' indicating more than one source. These ratings are used to determine delays which are perceived as a single source (receive a rating of ``0'') and delays which are perceived as multiple sources (receive a rating of ``100''). These anchor stimuli are then presented on each trial. The stimulus which received a rating of ``0'' is presented first, followed by the sound to be rated. The stimulus which received a rating of ``100'' is presented last. This procedure was used to determine fusion as a function of location and number of echoes presented. [Research supported by a program project grant from NIDCD.]