A study published in the June 2010 issue of Emotion, a journal of the American Psychological Association, examined if Botox injections have an effect on emotional experience.
To test if feedback from facial expressions influences emotional experience, Joshua Davis and Ann Senghas, Barnard College professors who led the research, compared the impact on self-reported emotional experiences of a group who had Botox injections, which paralyze muscles of facial expression, and a control group who had Restylane injections, a filler that does not affect facial muscles.
The abstract says, “When examined alone, Botox participants showed no pre- to post-treatment changes in emotional responses to our most positive and negative video clips.” However, comparing the Botox group to the Restylane group showed that Botox participants exhibited an overall significant decrease in the strength of emotional experience.
“With the advent of Botox, it is now possible to work with people who have a temporary, reversible paralysis in muscles that are involved in facial expressions,” said Davis. “With Botox, a person can respond otherwise normally to an emotional event, e.g. a sad movie scene, but will have less movement in the facial muscles that have been injected, and therefore less feedback to the brain about such facial expressivity. It thus allows for a test of whether facial expressions and the sensory feedback from them to the brain can influence our emotions.”
The findings suggest that feedback from facial expressions is not necessary for emotional experience, but may influence emotional experience in some circumstances.