Theories of vigilance

The inhibition hypothesis of vigilance, derived from the classical conditioning model, has too many weaknesses for an adequate theory. The "attention" hypothesis is too loosely stated to provide an acceptable model of vigilance behavior. Similarly the "expectancy" hypothesis lacks precision, but it has served to stimulate a number of experiments. A physiological model, labeled the activationist hypothesis, has so far only been useful in after-the-fact explanation. This hypothesis does offer some potentially important clues, but there is a need to coordinate the physiological components with the molar concepts.