Effects of Low-Pass Filtering on the Rate of Learning and Retrieval from Memory of Speech-Like Stimuli

Abstract

Ten pairs of auditory-visual stimuli were utilized in a paired-associate learning task and a retrieval from auditory memory task presented to two groups of normal-hearing subjects. One group heard unfiltered auditory stimuli and the other group heard the same stimuli under low-pass filtering conditions. The number of trials required to learn the pairs was the measure for the learning task. The number of items recalled after presentation of strings of the auditory stimuli, ranging in length from two to nine items, was the measure of auditory retrieval. Comparison of performance between the two groups indicated that the group that heard filtered auditory stimuli required a significantly greater number of trials to learn the pairs to specifications, and performed significantly poorer in recall of five-item strings of stimuli than the group that heard unfiltered auditory stimuli. There was no difference between the two groups' performance in recall of two-, seven-, and nine-item strings. The effects of filtering are discussed with regard to their implications for understanding certain deficits associated with hearing loss.