Spatial and temporal uncertainty as determinants of vigilance behavior.

Abstract

An experiment was conducted to evaluate the effects of temporal and spatial uncertainty on visual monitoring behavior in a complex vigilance task with spatially arranged stimulus sources. The 3 stimulus sources of the display were arrayed over 144[degree]. A 2 X 2 randomized factorial design was used, with temporal certainty and uncertainty about when a signal will occur as one dimension of the design, and spatial certainty and uncertainty about where a signal will occur as the other dimension. All Ss had a practice and a criterion session of 2.5 hr. duration, and there were 20 Ss in each of the 4 groups. Mean response latency for speed of signal detection increased as temporal and spatial uncertainty increased. Results were discussed in terms of temporal expectancies that cue S about the time of signal occurrence, and the observing response which directs S''s head and eyes for the reception of visual stimuli.