Experiments on vigilance: II. One-clock and three-clock monitoring.

Vigilance: A Review and Re-evaluation

“…Questions raised by Elliot (1960) on the "A effect," the low initial probability of detection, are therefore due to an artifact in measurement. In studies at this laboratory and elsewhere (Baker and Harabedian, 1962; Jerison, 1963;Jerison and Wallis, 1957;Kappauf and Powe, 1959) the decrement has been completed within 15 to 30 min after the beginning of a vigil, and performance has then remained at a plateau. Figure 2 illustrates the effect of changing the time grain on the appearance of the decrement function.…”

“…The absence of an apparent decrement in such tasks has been reported in many studies (see Frankmann and for a review). A careful analysis of the situation, however, suggests that a very rapid decrement may be completed within the first few minutes of vigils that last for several hours (Baker and Harabedian, 1962;Jerison and Wallis, 1957;Jerison, 1963).…”

The Effects of Signal and Response Complexity on Eighteen Hours of Visual Monitoring

“…One might expect that with such changes in the task requirements the monitoring behavior might also differ and that the effective variables might differ between the older and more modern situations. Research on monitoring tasks has, in fact, found no decrement in proficiency over time when more than one stimulus source was monitored (e.g., Howland, 1958;Jerison & Wallis, 1957). In a series of experiments using complex, persistent displays with multiple stimulus sources, Adams and his associates have found little, if any, vigilance decrement over several hours (Adams, 1963;Adams & Boulter, 1960, 1962Adams, Humes & Sieveking, 1963;Adams, Humes & Stenson, 1962;Adams, Stenson & Humes, 1961;Webber & Adams, 1964).…”

“…Generally, the most common finding reported is decrement in signal detections which occurs as a function of watchstanding time (Frankmann & Adams, 1962). In fact, this finding is so common in these tasks that Jerison and Pickett (1963) recommend that ''. .…”

Experimental Studies of Human Vigilance

“…Our predictions about the outcome of this experiment were unsure--partly because of the paucity of data from vigilance research on complex tasks, and partly because of uncertainties in predicting about molar behavior from the physiologically-based arousal hypothesis The few, earlier vigilanct studies that used complex tasks with multiple sources (Broadbent, 1950;Hoffman and Mead, 1943;Howland, 1958;Jerison and Wallis, 1957;Jerison and Wing, 1957;Loeb and Jeantheau, 1958) all found no decrement, so we were not sure that any decrement at all would be found for our experimental conditions. Conceivably, the increased stimulation in a complex task may be sufficient to deter all decrement, at least according to the arousal hypothesis, and no decrement should be expected whenever a task is sufficiently corr.…”