Subjects were shown either a list of non‐associated words or a list on which words could be organized into related groups. In Expt 1 either no orienting instructions were given or subjects had to rate the words for Pleasantness (semantic orienting task). The three‐way interaction of noise x list type x orienting task was significant. Eighty‐five dBC white noise compared with 65 dBC improved performance on the non‐associated list with no orienting task and increased recall in the original sequence, but had the reverse effect with semantic orienting. With the associated list noise had no marked effects in the non‐orienting condition, and improved performance in the orienting condition. It is concluded that in noise maintenance rehearsal tends to be adopted unless instructions induce an alternative strategy, and in the latter event noise reinforces use of the alternative strategy. In Expt 2, all subjects carried out a physical orienting task, rating the words for the sounds they contained. Noise aided performance on the non‐associated list and impaired it on the associated list. This result is taken to be compatible with the above interpretation of noise effects.

Eighty-five compared with 65 dBC white noise presented at input was found to improve the free recall of subjects expecting a recall test and to impair that of subjects anticipating a recognition test, suggesting that noise enhances differences in strategies between recall and recognition test expectations.presentation showed that test expectations had no effect on recall in the morning but influenced performance in the afternoon. Thus noise appears to reinforce the instructions and morning presentation to override them. task requirements. The results of a similar experiment examining the interaction between test expectations and time ofIt was concluded that the effects of noise and time of day must be considered in relation to the Influences of noise and time of presentation have typically been interpreted in terms of the inverted-U relationship between arousal and performance where an intermediate level of arousal is considered optimal for successful performance on a variety of tasks. For tasks involving short-term memory, however, an interpretation solely in these terms is somewhat limited, particularly in view of the more recent suggestion that arousal may affect performance qualitatively by influencing the types of strategy which subjects spontaneously adopt. Thus, for example, Folkard (1979Folkard ( , 1981 and Folkard & Monk (1979) have suggested that subjects place greater reliance on maintenance rehearsal in the morning (low arousal), and elaboration processing in the afternoon (high arousal). Conversely, the majority of studies using white noise have found that noise produces an increase in €he reliance on order information, suggesting it enhances the extent to which subjects subvocally rehearse or link items in order to aid retrieval. all obtained results where high intensity white noise tended to improve the retention of order information, although some studies have not produced an effect of noise on ordered recall (Miller