Effects of shifts in the rate of repetitive stimulation on sustained attention

Abstract

The effects of shifts in the rate of presentation of repetitive neutral events (background event rate) were studied in a visual vigilance task. Four groups of subjects experienced either a high (21 events/min) or a low (6 events/min) event rate for 20 min and then experienced either the same or the alternate event rate for an additional 40 min. The temporal occurrence of critical target signals was identical for all groups, irrespective of event rate. The density of critical signals was 12 signals/20 min. By the end of the session, shifts in event rate were associated with changes in performance which resembled contrast effects found in other experimental situations in which shift paradigms were used. Relative to constant event rate control conditions, a shift from a low to a high event rate depressed the probability of signal detections, while a shift in the opposite direction enhanced the probability of signal detections.

A Multilevel Approach to Relating Subjective Workload to Performance After Shifts in Task Demand

“…Perceptions of one's capacity to meet task demands, referred to as subjective workload, are typically assessed in retrospect to provide an indication of how individuals handled the conditions of stress. However, subjective workload's relationship with performance is characterized by inconsistent results (i.e., dissociation; Yeh & Wickens, 1988), showing a range of negative, positive, and null effects (Cumming & Croft, 1973;Goldberg & Stewart, 1980;Krulewitz, Warm, & Wohl, 1975;Matthews, 1986;Moroney, Warm, & Dember, 1995).…”

Effects of the rate and regularity of background events on sustained attention

“…Both the overall speed and the overall accuracy of critical signal detections vary inversely with the frequency of repetition of background events, or the background event rate (parasuraman, 1979;Parasuraman & Davies, 1976;Warm, 1977). Further, the deterioration of performance efficiency over time that typifies vigilance performance can be amplified or reversed by suitable variations in background event rate (Jerison & Pickett, 1964;Krulewitz, Warm, & Wohl, 1975;Wiener, 1977), and such variations can also modify the effects associated with other psychophysical parameters including the amplitude and probability of critical signals (Krulewitz & Warm, 1977;Metzger, Warm, & Senter, 1974). These results have led to the conclusion that background event rate is a prepotent stimulus factor in sustained attention (Dember & Warm, 1979).…”

Co-Adaptive Aiding and Automation Enhance Operator Performance

“…This is consistent with the expectation that effective aiding should reduce workload, leading to deactivation of the aiding, though simple errors in workload classification may also contribute. These factors result in more frequent transitions from both low to high workload and high to low workload; the performance effects of these transitions may have cancelled each other out (Matthews, 1986) or produced a net decline in performance (Krulewitz, Warm, & Wohl, 1975) relative to the less frequent transitions in the manually activated aiding condition. It is therefore possible that the observed improvement in performance with physiologically activated aiding would have been increased with less frequent transitions, perhaps achieved via a longer timeout between such changes.…”