Are emotions contagious? Evoked emotions while viewing emotionally expressive faces: quality, quantity, time course and gender differences.

In human interactions, frequently one individual becomes 'infected' with emotions displayed by his or her partner. We tested the predictions by Hatfield et al. (1992) (Primitive emotional contagion. Review of Personal and Social Psychology 14, 151-177) that the automatic, mostly unconscious component of this process, called 'primitive emotional contagion', is repeatable and fast, that stronger facial expressions of the sender evoke stronger emotions in the viewer and that women are more susceptible to emotional contagion than men. We presented photos from the Pictures of Facial Affect (Ekman and Friesen, 1976). (Pictures of Facial Affect. Consulting Psychologists Press, Palo Alto) on a PC varying the affective content (happy and sad), the expressive strength and the duration of presentation. After each photo, subjects rated the strength of experienced happiness, sadness, anger, disgust, surprise, fear and pleasure. Feelings of happiness or sadness were significantly, specifically and repeatedly evoked in the viewer - even with presentations lasting only 500 ms. Stronger expressions evoked more emotion. The gender of the viewer had weak effects. We hypothesize that this fast and repeatable reaction is likely to have a 'prewired' neural basis. We propose that the induction of emotional processes within a subject by the perception of emotionally expressive faces is a powerful instrument in the detection of emotional states in others and as the basis for one's own reactions. Detailed knowledge of emotional reactions to faces is also valuable as a basis for psychiatric studies of disorders in affect and/or communication and in studies using functional imaging (fMRI or PET) where faces are increasingly used as stimuli.