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Recent findings in stress research indicate the necessity for examining the distribution of the operator's attention in complex tasks as well as his information transmission capabilities. This study examines the effects of alcohol and noise on a complex tracking and signal-detection task with particular reference to changes in selective attention. The operator was instructed to give the tracking task priority. In noise tracking performance improved, but detection of lights placed on the periphery of vision was degraded. Alcohol had the same effect on peripheral detection, but tracking performance fell. It was concluded that the effect of alcohol on such simulated driving skills embodied two factors: the first an increase in attentional bias towards the high priority regions of the visual field, and the second a decrease in the information transmission rate. Since from the point of view of the tracking task these factors are mutually eLltagonistic, there may be an offsetting of the loss in transmission rate by more optimal dispositions of attention. The loss of peripheral awareness in this event is inevitable, and even at the low alcohol levels used was of apparently serious proportions. I 1 P S Y 61

Five experiments using the “running memory span” (RMS) technique are reported, in which subjects attempt to recall a specified number of items from the end of long sequences of digits, presented at a rate of 2/s. In Experiments I–III critical lists are included in the series which are exactly equal in length to the specified recall series. Despite the RMS set, these critical lists exhibit (I) marked primacy effects, and (2) an impairment in recall of terminal items (a “rebound effect”), compared to the baseline RMS performance. The rebound effect occurs (Experiments IV and V) even when recall of earlier items is not required. These two phenomena are robust: they occur in different experiments in which, rehearsal patterns, report order, expectancies and retrieval load are controlled. The results suggest an origin for primacy which is of a perceptual (i.e. pre-storage) nature, and that selective rehearsal is not a necessary condition for the effect to occur. A possible role of habituation of the orienting response in this phenomenon is discussed.