galvanic skin response

n.
A change in the ability of the skin to conduct electricity, caused by an emotional stimulus, such as fright.

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A transient change in certain electrical properties of the skin, associated with the sweat gland activity and elicited by any stimulus that evokes an arousal or orienting response. Originally termed the psychogalvanic reflex, this phenomenon became known as the galvanic skin response. Electrodermal response (EDR) has replaced galvanic skin response as the collective term.

The skin of a relaxed person has a low electrical conductance (high resistance), and the skin surface is some 40 mV negative with respect to interior tissues. Sweat gland activity changes these electrical properties by increasing skin conductance and by changing the balance of positive and negative ions in the secreted fluid.

Tonic skin conductance varies with psychological arousal, rising sharply when the subject awakens and rising further with activity, mental effort, or especially stress. Phasic skin conductance responses are wavelike increases in skin conductance that begin 1–2 s after stimulus onset and peak within about 5 s. The amplitude of the skin conductance response varies with the subjective impact of the eliciting stimulus, which in turn varies with the intensity of the stimulus, its novelty or unexpectedness for the subject, and its meaning or signal value. Aroused subjects display spontaneous skin conductance responses, generated apparently by mental events or other internal stimuli; their frequency, like the tonic skin conductance level, increases with the level of arousal.

Electrodermal responses are measured in studies of emotion and stress, conditioning, habituation, and cognitive processing, that is, when it is desired to assess the differential or changing impact of a series of stimuli. See also Electroencephalography; Lie detector; Sympathetic nervous system.

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In marketing research, clinical measurement of a subject's response to stimuli, such as an advertisement, in terms of changes in skin resistance to electrical current; also called psychogalvanic skin response or sweaty palms. Theoretically, the greater the change in resistance, the more positive the subject's reaction to the stimuli. The validity of this technique has been much disputed, particularly because there is no way of knowing for sure that the stimulus provided by the researcher (the advertisement) was the cause of the response. Its proponents argue that it is more objective than research that relies on voluntary responses like interviews or surveys. See also eye movement analysis.

Response of the skin to the passage of a small electric current. The ease with which the current flows between two points on the skin can be used to indicate stress. When a person is tense or emotional, the sweat glands become more active, increasing moisture on the skin; this allows the electric current to flow more readily. The response may also be used in relaxation training: information about the galvanic skin response is fed back aurally or visually to the subject who can, with practice, learn to increase or decrease sweating on the skin by learning to relax or tense muscles (see biofeedback).

n
GSR

A reaction to certain stimuli as indicated by a change in the electric resistance of the skin. The GSR is used in some polygraph examinations.