Clinical studies suggested that errors of tactile localization made by leucotomized subjects were due to a failure of analysis of a conceptual type. The present experiment examines the normal mechanisms of localizing stimuli to different sites on the hands by measuring the time taken to make a correct response as well as by an analysis of the errors made under conditions of stress (the reaction-time situation). It is demonstrated that healthy subjects of above-average intelligence have appreciable difficulty in determining which of their fingers has been touched. The degree of this difficulty depends on which finger has been stimulated. The results strongly support the hypothesis that normal tactile localization involves the analysis of primary sensory data in terms of a few simple parameters of orientation. It is suggested that some of the errors which occur are due to contamination between different systems of conceptual analysis.
In a previous communication Elithorn, Piercy, and Crosskey (1955) reported changes in autonomic reactivity which followed prefrontal leucotomy. The change in reactivity which was observed was related to the kind of stimulus which elicited the reponse. It was suggested that the autonomic reactions in a painful situation were changed by leucotomy in that there was a marked reduction of the anticipatory component which appears in association with subjective anxiety.Although the evidence suggested that most of the differences which were observed were directly related to the post-operative changes in the clinical picture, the surgical intervention might have modified autonomic activity in a way which was not closely related to behaviour or to subjective experience. In order further to elucidate the relations which obtain between patterns of autonomic reaction and emotional mechanisms we have undertaken a study of psychiatric patients using a " pain expectancy " technique similar to that used in the studies of leucotomized patients. The autonomic responses occurring with pain and with the anticipation of pain have a more obvious relationship with anxiety than with any other major psychiatric symptom. Accordingly, in this study the guiding principle in interpreting individual differences in autonomic reaction has been the extent to which anxiety was a clinically prominent symptom. Experimental MethodsThe apparatus and procedure employed in this investigation for measuring autonomic reaction was essentially the same as that described in the previous communication and is now described only in outline.Changes in the electrical resistance of the palmar skin (psychogalvanic responses) were recorded graphically (a) following an electrical stimulus to the little finger and (b) following a red light which was exhibited for a short interval (about 400 millisec.) eight seconds before the onset of the electrical stimulus. Successive electrical stimuli were increased in intensity in regular steps from a subliminal value to the maximum intensity the subject would tolerate. Preliminary tests were carried out with each subject to determine the approximate intensities at which the stimulus was first perceived and at which it became as much as the subject said he could bear. The voltage increment for successive stimuli was then calculated for the individual subject so that approximately 16 supraliminal stimuli were administered before the subject said " stop ". The procedure was explained to the subject before the experiment began and he was asked to say " stop" when the electrical stimulus became " too painful ". No further electrical stimuli were given after the subject said " stop ", and this was made clear to the subject from the outset. After the subject had said "stop" the red light was exhibited three more times, but it was not followed by a shock. After he had said " stop " the subject was told to expect this. Measurements were also taken of the resting level of skin resistance, skin temperature, and environmental temperature. ...
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