INFORMATIONAL PROCESSING OF COMPLEX SOUND .2. CROSS-DIMENSIONAL ANALYSIS

A series of experiments investigated listeners ability simultaneously to process information across different acoustic dimensions. On each trial, the listener heard a pair of brief n-tone sequences (n = 1 to 12). The frequency, intensity, and duration of each tone in the sequence varied randomly from trial to trial. On average, the values of these three parameters were greater for one sequence, the target, than the other, the nontarget. The listener’s task was to identify the target on each trial. For an ideal observer in this task, d performance grows as the square root n. Obtained d grew at a rate slightly less than the square root of n. Close to cube root of n growth was observed when the average difference occurred in only one of the three tone parameter values within a block of trials. Although performance fell short of ideal, optimum weights were consistently given to each tone and each parameter. The results are consistent with a model in which performance depends predominantly on the information content of the sounds regardless of how the information is “packaged” in the stimulus. Transmitted information is estimated to be 0.9-2.0 bits within a single acoustic dimension, 2.1-3.0 bits when distributed across dimensions. © 1990, Acoustical Society of America. All rights reserved.