Galvanic skin response
Galvanic skin response (GSR), also known as
electrodermal response (EDR),
psychogalvanic reflex (PGR), or
skin conductance response (SCR), is a method of measuring the
electrical resistance of the
skin. There has been a long history of electrodermal activity research, most of it dealing with spontaneous fluctuations. Most investigators accept the phenomenon without understanding exactly what it means. There is a relationship between sympathetic activity and emotional arousal, although one cannot identify the specific emotion being elicited. The GSR is highly sensitive to emotions in some people. Fear, anger, startle response, orienting response and sexual feelings are all among the emotions which may produce similar GSR responses.
One branch of GSR explanation interprets GSR as an image of activity in certain parts of the body. The mapping of skin areas to
internal organs is usually based on
acupuncture point.
GSR is conducted by attaching two leads to the skin, and acquiring a base measure. Then, as the activity being studied is performed, recordings are made from the leads. There are two ways to perform a GSR - in active GSR,
current is passed through the body, with the resistance measured. In passive GSR, current generated by the body itself is measured.
GSR originated in the early
1900s. It was used for a variety of types of research in the
1960s through the late
1970s, with a decline in use as more sophisticated techniques (such as
EEG and
MRI) replaced it in many areas of psychological research. GSR still sees limited use today, as it is possible to use with low-cost hardware (
galvanometer).
GSR has seen usage as a
lie detector, under the theory that telling of lies increases
perspiration, changing the
conductance of skin. However, the variety and rapidity of some responses disproves this theory, as skin would have to 'un-sweat' or dry out in remarkable ways. Its accuracy, because of its limited scope, is believed to be even less significant than that of a regular
polygraph.
GSR is also used by
Scientologists, who call their devices
E-meters, in their spiritual counseling. They claim to have developed a variety of techniques to improve the reliability and accuracy of the device.
*
Electrical quackery*
Electroacupuncture*
Affective computing*
University of Kuopio page on GSR Use*
Quack "Electrodiagnostic" Devices by
Stephen Barrett, M.D. (a
Quackwatch paper)
