Facial temperature depends on the arousing content of emotional pictures

It’s well known that faces are an important vehicle for emotional communication. Considering that the facial thermography, an upcoming technique of psychophysiology, can detect cutaneous thermal variations related to emotional stimulations, this study aims to explore whether the facial temperature is sensitive to the valence and arousal of emotional pictures. We measured the facial temperature from the nose, a major region of interest for facial thermal variations. Simultaneously, skin conductance responses (SCRs) and heart rate (HR), robust indices of emotional activations, were recorded in 24 healthy participants in response to neutral, unpleasant and pleasant pictures (the two latter were equalized in arousal). There were six blocks (two for each category) with 10 pictures presented for 4 s with a 3 min rest period between blocks. The peak amplitude of temperature decrease was greater for unpleasant and pleasant pictures than for neutral pictures . The peak latency of temperature decrease was shorter for unpleasant and pleasant pictures . Amplitude and frequency of SCRs together with HR showed classical modulations: unpleasant and pleasant pictures provoked greater changes than neutral ones in SCR amplitude , SCR frequency and HR deceleration . No valence effect was observed. Overall, the facial temperature varies as a function of arousing content of emotional pictures and reflects sympathetic activation, as showed by electrodermal measures.