Galvanic Skin Response (GSR) is a technology used to measure the emotional response of the participant to a given stimulus. The GSR technology measures the variations in electrical impedance of the skin. It is commonly used with other technologies such as Plethysmography and Temperature in order to complement and validate the GSR measures. The Plethysmograph measures the oxygen concentrations in the blood while a thermal conductivity sensor is used to measure the temperature of the skin. Plethysmograph data is used to calculate the heart beats per minute. The GSR, the heart beats per minute and the temperature levels are expected to increase with the emotional arousal.
The Edmond J. Safra Brain Research Center for the Study of Learning Disabilities acquired GSR, Plethysmography and Temperature extensions for its EEG device from Biosemi. These extensions allow researchers to conduct studies that explore the emotional responses of the participants to learning tasks (such as mathematics or reading). For example, it can be used to assess the emotional response of the dyscalculic population to numerical stimuli. Furthermore, such measures can be easily added to neurocognitive studies since the GSR, Plethysmography and Temperature technologies are included in the same EEG device.
The GSR extension consists of a cord whose two electrodes are attached, using conductive gel, to the hand of the participant. The Plethysmograph is connected to one of the fingers of the participant’s hand using a special cable with an infrared sensor. The Temperature sensor is also attached to the participant’s hand.