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Skin conductance as a measure of tonic and phasic arousal
Acta Psychoiogica 27 (X967) 262; 0 North-H&nd Publishins Co., Amsterdbn WetTVbr repro&zced by photoprint or microfilm without written permission from the publisher
SKIN CON:DUC’~ANCE
AS A MEASURE
OF TONIC AND PHASIC
AROUSAL E..
H. VAN Free
OLST,
J. F. ORILEBEKEand S. D. FOKICEMA
CMvrsity,
Amsterdam, The Netherlands
This paper offers a number of suggestions, that are inspired by current exp&.mental literature and neurophysiological findings. It stems possible to d&tinguish a tonic arousal and a phasic arousal, as neurophysiological states of the organism. Notwithstanding their functional &era&on, in experiments both types, of arousa1 can be very well independently studied. Tonic arousal is an organistic state of vigilance of a rellativeiy permanent character and not within short time-ranges dependent upon stimulus conditions, Phasic arousal is a respondent state of vigilance increment of short e.ndurance and dependent upon the stimulus conditions of noveby and others,. There are a number of reasons for a preference to measure both types of arousal peripherally by skin conductance measurement, instead of measurement by EEG. Evidence has been collected, that the BLC is an appropriate measure of tome arousal. We have been able to demonstrate the well-known inverted U-shape function of performance variables in relation to degree of BLC. Phask arousal seems to be measurable by skin conductance changes. In mtal practice data on skin conductance changes (EDR) are reported in a variety of scales: absolute change in conductance, change as a aetio of the basic conductaztcr level (BLC), and log conductance change. Explorative studies in our laboratory have shown that the respective relationships of these EDR scales with the BLC are different. It is very nessary that these relationships will be further studied. In the use of data on phasic arousal for inferences on activation-level (tonic arousal) the nature of the experimental variables and the scales: used, reqrire serious consideration.
262
SKIN CON:DUC’~ANCE
AS A MEASURE
OF TONIC AND PHASIC
AROUSAL E..
H. VAN Free
OLST,
J. F. ORILEBEKEand S. D. FOKICEMA
CMvrsity,
Amsterdam, The Netherlands
This paper offers a number of suggestions, that are inspired by current exp&.mental literature and neurophysiological findings. It stems possible to d&tinguish a tonic arousal and a phasic arousal, as neurophysiological states of the organism. Notwithstanding their functional &era&on, in experiments both types, of arousa1 can be very well independently studied. Tonic arousal is an organistic state of vigilance of a rellativeiy permanent character and not within short time-ranges dependent upon stimulus conditions, Phasic arousal is a respondent state of vigilance increment of short e.ndurance and dependent upon the stimulus conditions of noveby and others,. There are a number of reasons for a preference to measure both types of arousal peripherally by skin conductance measurement, instead of measurement by EEG. Evidence has been collected, that the BLC is an appropriate measure of tome arousal. We have been able to demonstrate the well-known inverted U-shape function of performance variables in relation to degree of BLC. Phask arousal seems to be measurable by skin conductance changes. In mtal practice data on skin conductance changes (EDR) are reported in a variety of scales: absolute change in conductance, change as a aetio of the basic conductaztcr level (BLC), and log conductance change. Explorative studies in our laboratory have shown that the respective relationships of these EDR scales with the BLC are different. It is very nessary that these relationships will be further studied. In the use of data on phasic arousal for inferences on activation-level (tonic arousal) the nature of the experimental variables and the scales: used, reqrire serious consideration.
262