Noise and the "rehearsal-masking hypothesis"

This study examines the proposal that continuous loud noise impairs short-term recall by masking the inner speech necessary to rehearse material in memory (Poulton, 1976 a, 1977 b). The "masking hypothesis" contrasts with previous theories which relate recall impairment in noise to the latter's action in over-arousing the individual or inducing changes in attentional deployment. Separate groups performed a visual, serial eight-consonant recall task in either 92 dBA "noise" or 75 dBA "quiet" and in "normal" or "suppressed" rehearsal conditions. The masking hypothesis predicted that noise would impair recall relative to quiet in normal rehearsal conditions. But where the rehearsal of both groups was already suppressed by a concurrent articulatory task, recall would not differ between the groups through noise-masking then being irrelevant. Total correct recall scores appeared to confirm the masking hypothesis but the pattern of serial order recall showed differences between noise and quiet in suppressed rehearsal conditions which seemed better explained by an attentional influence of noise. Further, reduced commission and acoustic confusion errors in noise were not consistent with the predictions of the masking hypothesis. It was concluded that noise-masking could not be refuted but that attentional changes due to the arousing action of noise might also be active determinants of recall.