Electrodermal Response (EDR)
Electrodermal response (EDR) is more popularly known as electrodermal activity (EDA) or galvanic skin response (GSR). It is also referred to as skin conductance, psychogalvanic reflex, and skin conductance level (SCL), and sympathetic skin response (SSR). EDR pertains to sweat gland activity changes due to emotional arousal, both positive and negative. This is assessed by placing electrodes on the skin (usually on the hand, foot, or shoulder) which apply a very low and undetectable voltage. The connected device measures the activation of sweat glands as manifested by skin moisture.
EDR is often used in research on emotional and cognitive states, in biofeedback therapy to help the patient control his anxiety, and as a component of polygraphs or lie detectors. For instance, a spike of your sweat gland activity may be recorded when you are talking about a scary experience. This is also the science used in polygraph testing