Facial feedback hypothesis

The facial feedback hypothesis, rooted in the conjectures of Charles Darwin and William James, is that one's facial expression directly affects their emotional experience. Specifically, physiological activation of the facial regions associated with certain emotions holds a direct effect on the elicitation of such emotional states, and the lack of or inhibition of facial activation will result in the suppression (or absence altogether) of corresponding emotional states.^[1]

Variations of the facial feedback hypothesis differ in regards to what extent of engaging in a given facial expression plays in the modulation of affective experience. Particularly, a "strong" version (facial feedback is the decisive factor in whether emotional perception occurs or not) and a "weak" version (facial expression plays a limited role in influencing affect). While a plethora of research exists on the facial feedback hypothesis and its variations, only the weak version has received substantial support, thus it is widely suggested that facial expression likely holds a minor facilitative impact on emotional experience. However, a 2019 meta-analysis, which generally confirmed small but significant effects, found larger effect sizes in the absence of emotional stimuli, suggesting that facial feedback has a stronger initiating effect rather than a modulating one.^[2]

Further evidence showed that facial feedback is not essential to the onset of affective states.^[3] This is reflected in studies investigating emotional experience in facial paralysis patients when compared to participants without the condition. Results of these studies commonly found that emotional experiences did not significantly differ in the unavoidable absence of facial expression within facial paralysis patients.^[4]