THE EXPERIENCE of anxiety appears to offer opportunities for experimental study and objective measurement with a precision lacking in other psychological states. Anxiety is in varying degree universal and the relative ease with which it may be evoked facilitates investigation. There is a growing but still inadequate understanding of the neurophysiological basis of arousal states, higher levels of which include anxiety. Centrally, activity of the reticular formation and hypothalamus are involved, with peripheral effects upon the autonomic nervous system, the adrenal medulla, and the pituitary-adrenocortical system. Hence the postulation that the degree of emotional disturbance experienced may be quantified by measuring the responses of these systems.
There are a number of methodological and theoretical problems implicit in the assumptions made in such work. Firstly, it is not easy to define a state of anxiety and it is even more difficult to