AUTONOMIC NERVOUS-SYSTEM RESPONSE PATTERNS SPECIFICITY TO BASIC EMOTIONS

The aim of this study was to test the assumption that the autonomic ne rvous system responses to emotional stimuli are specific. A series of six slides was randomly presented to the subjects while six autonomic nervous system (ANS) parameters were recorded: skin conductance, skin potential, skin resistance, skin blood flow, skin temperature and inst antaneous respiratory frequency. Each slide induced a basic emotion: h appiness, surprise, anger, fear, sadness and disgust. Results have bee n first considered with reference to electrodermal responses (EDR) and secondly through thermo-vascular and respiratory variations. Classica l as well as original indices were used to quantify autonomic response s. The six basic emotions were distinguished by Friedman variance anal ysis. Thus, ANS values corresponding to each emotion were compared two -by-two. EDR distinguished 13 emotion-pairs out of 15. 10 emotion-pair s were separated by skin resistance as well as skin conductance ohmic perturbation duration indices whereas conductance amplitude was only c apable of distinguishing 7 emotion-pairs. Skin potential responses dis tinguished surprise and fear from sadness, and fear from disgust, acco rding to their elementary pattern analysis in form and sign. Two-by-tw o comparisons of skin temperature, skin blood flow (estimated by the n ew non-oscillary duration index) and instantaneous respiratory frequen cy, enabled the distinction of 14 emotion-pairs out of 15.9 emotion-pa irs were distinguished by the non-oscillatory duration index values. S kin temperature was demonstrated to be different i.e. positive versus negative in response to anger and fear. The instantaneous respiratory frequency perturbation duration index was the only one capable of sepa rating sadness from disgust. From the six ANS parameters study, differ ent autonomic patterns were identified, each characterizing one of the six basic emotion used as inducing signals. No index alone, nor group of parameters (EDR and thermovascular for instance) were capable of d istinguishing each emotion from another. However, electrodermal, therm o-vascular and respiratory responses taken as a whole, redundantly sep arated each emotion thus demonstrating the specificity of autonomic pa tterns.