DECISION INTERVAL AND SIGNAL DETECTABILITY IN A VIGILANCE TASK
DEFENCE RESEARCH MEDICAL LABS TORONTO (ONTARIO)
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The paper discusses the effect of the assumed decision interval on the measurement of d. Previous experiments have revealed a decrement in the detectability d of signals during a particular vigilance task involving the detection of a brief pause in the movement of a clock hand. In order to measure the false alarm probability, Ss were required to make a decision once every five sec. as to whether or not there had been a signal in the previous five sec. In this paper Ss were required to respond as soon as they saw a signal, and it was assumed that the decision interval was the signal duration. The thirty-fold change in assumed decision interval produced very little change in the decrement in d during the run. It is therefore concluded that the length of the assumed decision interval was not a critical factor in determining changes in d during the continuous clock task.