Skin Conductance (SC) is the measurement of the electrical conductivity of the skin. It reflects the level of psychological or physiological arousal, elicited by cognition or emotions. Skin conductance is measured with two electrodes preferably on the fingers or hand. A tiny bit of current runs from one electrode to the other. The sensor attached measures conductivity of the current running through this circuit.
Measuring skin conductance is based on the following mechanism: Special types of sweat glands (the ‘eccrine sweat glands’ located on the palms of the hands and soles of the feet) respond primarily when the body is sympathetically activated. The more the body is activated, the more sweat is secreted by these glands. As sweat is comprised of salt water which can conduct electrical signals, therefore the more sweat produced, the greater the flow of electricity.
Skin Conductance is a way of measuring the Electro Dermal Activity (EDA). EDA is a frequently used measure as it is non-invasive and responds quickly to emotional and psychological stimuli. Historically, EDA is used in lie detection. Nowadays, EDA is often applied in psycho physiological studies and treatment.