Ingelise J. Loy
Robert J. Zatorre
Dept. of Psychol., McGill Univ., and Montreal Neurological Inst., 3801 University St., Montreal, PQ H3A 2B4, Canada
Memory for the location of auditory stimuli was tested after delays of 1 min, 30 min, or 24 h. Eleven environmental sounds were presented to 22 subjects in each of 11 different free-field positions, spaced evenly in a semicircle around the subject in the horizontal plane. Initial localization acuity was recorded upon presentation of each stimulus. To test memory for location, target stimuli were presented over headphones, and subjects attempted to recall the original position. Memory for location was significantly less accurate than initial localization, even after 1 min. Male subjects' accuracy decreased over time, but there was no effect of delay for female subjects. A large effect of stimulus position was also noted, with stimuli coming from central locations remembered better than those coming from the extremes, an effect not accounted for by azimuthal differences in localization accuracy. Analysis of the error distributions indicated that this pattern was largely due to the presence of right--left reversals. These reversals suggest the existence of two separate components to auditory spatial memory: side and azimuth, and that these two parts can be dissociated.