Vigilance Missed Signals May Have Preferred Average Lags

Abstract

The randomness of average missed signal lags (AMSL) in experiments on vigilance was investigated. This measure was taken from group data in a sample of 116 published visual reports (on which an ad hoc cluster analysis was carried out) and from the 1966 results for 48 subjects tested by Smith, Lucaccini, Groth, and Lyman. Evidence of a 4-min. periodicity was found. This apparent effect of a biorhythm may extend the explanation of the absolute level of performance and, possibly, of the vigilance decrement. Depending on the effect-size, it might also have relevance for the practical problem of the maintenance of alertness.