The effects of "unwanted" signals and d-amphetamine sulfate on observer responses.

The effects of unwanted signals and d-amphetamine sulfate on observer responses (OR) in a 2-hour vigilance task were studied. Scope observation was contingent on a lever press (OR). 8 different schedule of frequency and regularity of unwanted conditions were used involving 8 independent groups of 4 Ss each. The effects of oral ingestion of placebo and drug were also tested. Increasing the frequency and irregulants of unwanted signals without drugs markedly increased frequency and rate of OR. This effect was enhanced under placebo and drug. Variance due to individual differences lessened as reinforcement from unwanted signals and drugs increased. Hypotheses based on activation theory emphasizing arousal aspects of vigilance behavior were verified. (PsycINFO Database Record (c) 2010 APA, all rights reserved)