No abstract

In the present study, which is based on Loeb's 1986 analysis, we used five levels of noise that varied in intermittency and meaningfulness, crossed with sex of subject and time of day. Memory tasks that differed in their reliance upon long-term, short-term free recall, and sequential short-term memory were used as dependent variables. A total of 160 subjects, 20 per block, participated in the 2 x 2 x 5 (Sexes x Time of Day x Noise Conditions) experimental design. Results support the prediction that white noise enhances performance on tasks with sequential short-term memory demands (anagrams: p < .05; random letter generation: p < .002). We found complex interactions by sex of subject, time of day, and type of noise for those tasks that placed a heavy demand on short-term working memory, i.e., complex sorting (Noise x Sex, p < .05) and random letter generation (Sex x Noise x Time of Day, p < .05). The predicted effects for anagrams were not supported. These results call into question previous generalizations about the effects of noise on performance (Broadbent, 1978; Dornic, Sarnelid, Larson, Svensson, & Fernaeus, 1982; Poulton, 1977), alternative interpretations are presented.

The present study investigates changes in auditory threshold during 4-6 week intervals for men, women on birth control pills, and normal cycling women not on birth control pills. Thresholds were determined at 250, 500, 1,000, 2,000, 4,000, 6,000, 8,000 Hz. Normal cycling females had significantly lower thresholds during first half of the menstrual cycle than during the second half. Females on birth control pills showed significantly and consistently lower thresholds than other listeners at several frequencies. Explanations for the phenomena are proposed.

It was suggested that insights into feature analysis of processes involved in form identification might be gained from an analysis of eye movements made by Ss as they identified patterns. Fixations were measured during identifications of histoforms, polygons, and Vargus 10 figures. Eye fixations were measured, and Ss rated sections of the figures in terms of their importance. Eye fixations were measured in terms of number of changes and duration of fixations, The number of changes in fixation were found to reflect only individual differences. Duration of fixation was found to vary significantly with location within figures, with fixations being longest where changes of contour occurred. There was also a tendency to look longer at the top of polygons and Vargus 10 figures and at the center of histoforms. Ratings of importance were highest for sections of figures fixated for longer duration-generally areas in which changes of contour were present.

The present review considers a series of studies of noise conducted in collaboration with Dr. Michel Loeb. This review attempts to provide a theoretical perspective as well as to summarize the most important findings of those studies. The work reviewed shows that noise effects interact with other variables, such that a noise effect on one sex is reversed for the other, and is also reversed at different times of the day. A second experiment confirmed this finding with a different arithmetic task. Further work indicated parallels between noise and fatigue, with aftereffects depending upon both work and noise. The final experiment repeated some of these findings with a different task battery of information processing tasks while showing that noise effects further depend on the meaningfulness of the noise background.