Abstract
In recent, years the importance of perceptual and central organizing activities in sensory-motor performance has been increasingly recognised and progress has been made towards a genuinely quantitative treatment. This paper sketches the historical development of the work in this area and attempts a reappraisal under five main heads : (a) There appears to be in the central mechanisms a ‘ single channel ’ which deals with signals or groups of signals one at a time so that signals coming in rapid succession may have to ‘ queue ’ before they are dealt with. (b) Choice reaction times are discussed in relation to the theory that the subject gains information, in the information-theory sense of the term, at a constant rate. Conceptual models of the subject's detailed behaviour when making choices are also considered. (c) Information theory models relating to the speed and accuracy of movement arc outlined and discussed. (d) Several formulae attempting to relate time taken to discriminate quantities of different magnitudes and the fineness of the difference between them are examined. (e) A number of wider implications of the work surveyed are outlined. Perhaps the most important of these are now approaches to ‘ mental ’ and monitoring tasks which have so far not been amenable to the normal methods of work study. It is concluded that there is a need for joint psychological and physiological research which would be able to go beyond descriptive mathematical formulae to the study of detailed micro-behaviour and neuro-muscular mechanisms.