Types of music, schedules of background stimulation, and visual vigilance performance.

Studies demonstrating that background auditory stimulation affects vigilance performance have both practical implications, especially in industrial settings, and theoretical implications, especially for arousal theory. Davenport (1974) investigated the effects of background music on an observer's monitoring efficiency in a visual vigilance task. His music was background-type instrumental music, and he used continuous music, music under a fixed interval temporal schedule, music under a variable interval temporal schedule, and music under a random interval temporal schedule. Responding to vertical signals made on a static sine-wave pattern on an oscilloscope was best under the random interval, followed closely by the variable interval, with the other two schedules being similar and less effective. As a follow-up, the present study examined effects of different types of music on performance on a signal detection task, using thrce of the same temporal schedules. This study employed the same type of relaxing instrumental music along with a more vigorous form of contemporary vocal and instrumental rock music (both at 70 db). On the basis of arousal theory and in accordance with previous studies, the vigilance task should be more efficiently performed under a random condition than under either a fixed interval or continuous schedule for both rypes of music. Also, the more vigorous rock music should be associared with better performance than rhe instrumental music. The basic procedure was identical to Davenport's (1974). Subjects responded to a signal which was a .SO-sec. increase in amplitude (.05 v added to a baseline of .20 v/un: 5 cm basic amplitude) of a static sine-wave pattern presented on an IBM Type 535 oscilloscope, by indicating as quickly as possible whenever they detected a signal. The intersignal intervals were those used by Davenport (1974). Half of the subjects heard easylistening music and half heard rock music. Davenport's continuous, fixed interval, and random interval schedules were used as a within-subjects variable (see Davenport, 1974, for specific details on these schedules). Complete berween-subjects counterbalancing of schedules was used. Each schedule was presented for 20 min.. making a total watch of 60 min. Three male and three female undergraduates were randomly assigned to each type of music. Subjects made very few false positive errors, and no systematic differences in these errors were apparent. A two-way analysis of variance on the number of correct detections showed performance was significantly better with the rock than with the easy-listening music (F = 10.29, df = 1/10, p < .01) and was a function of the schedules of background stimulation (F = 164.36, df = 2/20, p < .001). More correct detections were made with the random interval (M = 21.92, SD = 2.75) than with the fixed interval (M = 17.00, SD = 2.04) schedule (Duncan's range test, p < ,001). Both schedules led to greater accuracy than the continuous music (M = 14.67, SD = 2.81, Duncan's range test, p < .05). Performance under the three schedules did not differ as a function of type of background music. It appears vigilance performance is best when background stimulation is discontinuous and contains elements of uncertainty (as in the rock music which was more diversified, vigorous, and changeable than the easy-listening music).