Effects of Practice on Visual Monitoring

Although the problem of human monitoring has been the subject of considerable study, relatively few attempts have been made to decermine whether or not signal detection can be improved with practice. Of the few studies that are available, as far as the authors are aware, only three bear directly on practice effects in vigilance tasks. Buckner, et al. (1960) failed to find practice effects in a study combining visual discrimination and v~gilance. They did, however, obtain some improvement with a similar auditory task. Another study by Webb and Wherry (1960), designed specifically to measure the effects of such practice, found no change in the detection of auditory signals. A replication of this study by Ware, Sipowicz, and Baker (1961) also failed to find any improvement directly attributable to practice. With regard to practice effeccs on visual monitoring, however, the Buckner study did require that Ss discriminate between a standard and a signal light source. Moreover, their primary purpose was to determine individual differences in monitoring ability rather than to study the effeccs of practice only. That Ss in the Buckner study did not show improvement with practice may well have been due to their failure to discriminate between the standard and signal light sources. So, it was believed desirable to extend and repeat the Buckner study using a visual monitoring task free of the discriminatory aspect.