ABSTRACT
Drives, it seems, were conceived as a result of the marriage between mechanical and purposive theories which took place during the period between the two world wars. They contained features of both parents-the suggestion of striving together with that of push from behind favoured by mechanical theorists since Descartes. The apparatus of drive-receptors and drive-stimuli, which, to put it mildly, is highly conjectural, preserved the picture of impulses being transmitted internally to parallel the model of external stimulation. The chapter mainly focuses on drive theories of Hull and Tolman. The concept of 'drive', employs the mechanical model of stimulation, has therefore the effect of blurring important distinctions by assimilating all behaviour to a type which seldom occurs-at least amongst men. Most of the obnoxious implications of drive-theories could be avoided if they were stated in terms of need-reduction. Needs do not really enter in the control of behaviour, except in the long run through the mediation of natural selection'.
