The disorganization of behaviour in fatigue.

MANY studies of mental fatigue have been governed by the expectation that its effects were to be found in a decline in the quantity or quality of the output, and tests have been employed in them involving the repetition of elementary operations. Bartlett (1943) contended, however, that effects related to real life were to be found in the disorganization of skilled activities, of which the work of every-day life largely consists. He therefore proposed that the organization of a relatively complex skill should be studied under conditions which might reasonably be assumed to be fatiguing. This was made possible by an ingenious apparatus, now called the Cambridge Cockpit, which was designed and built by the late Dr. K. J. W. Craik. Bartlett has described some of the results of the first experiments with this apparatus, which were carried out by Drew, and has shown how they throw light on the organizing functions of the central nervous system. He has referred mainly to the perceptual aspects of the disorganization. This paper, based upon further experiments by the author, amplifies Bartlett's account in several respects and deals mainly with the motor aspects.