Botox blunts emotional understanding, study finds

Botox injections can erase the effects of years of emotional expression on a person’s face. But the cosmetic procedure that unfurrows brows, smoothes laugh lines and unwrinkles crinkles appears to come with an unseen price: an impaired ability to read others’ emotions.

A new study has found that when it comes to reading expressions of emotion on the faces of people in photographs, women who received Botox injections in their face were less accurate than those who had their facial lines plumped with an injectable cosmetic filler. The research contributes new evidence to a key theory about communication between humans: that we unconsciously use facial mimicry to help discern and interpret the emotions of others.

The Botox effect emerged from a novel pair of experiments conducted by researchers from USC and Duke University. They are described in an article published this week in the journal Social Psychological and Personality Science.

Why would Botox injections blunt a person’s ability to interpret another’s fear, worry, joy or sadness, while dermal fillers (sold under such commercial names as Restylane site” href="" target="_blank">Restylane or Juvederm) do not? The study’s lead author, USC psychology professor David T. Neal, surmised that it is Botox’s hallmark paralyzing effect on facial muscles in the immediate vicinity of the injection site that would negatively affect a person’s ability to read another’s emotional state.

With key areas surrounding his or her eyes immobilized by Botox, subjects would be unable to reproduce fully the emotional expression of a conversation partner. Because mounting evidence suggests that we use mimicry to register and label the emotional states of others, a procedure (or a disorder or injury) that limits our ability to reproduce another person’s expression of emotions would likely impair our ability to register or label those emotions, Neal said.


Indeed, the difference was considered statistically significant: While women who had had their facial folds treated with Restylane were able to read others’ emotional states with about 77% accuracy, those who had had Botox treatment accurately interpreted the emotions of photographed individuals 70% of the time.

Neal’s work underscores that the vaunted connection between mind and body works in both directions. Although most research focuses on the mind’s power over the body -- to heal itself, to produce phantom pain, to respond to sham therapies -- the latest study on “embodiment” suggests that our bodies, too, provide important feedback that help us in matters of the mind: navigating our social world, sharing or responding to a partner’s mood, making sense of our own emotional reactions.

“Our ability to read others’ emotions isn’t something that takes place solely in the head,” Neal said. “Our emotional intelligence does depend partly on our ability to listen to our own bodies, and if we don’t or can’t do that, our emotional world gets diminished.”

Neal said that his team’s findings are consistent with the growing belief among neuroscientists that specialized neurons, or brain circuits, help us understand the emotions and motives of others by effectively “mirroring” the moods and responses we perceive in them. That “embodiment,” or physical mimicry of those moods and responses, may be processed in regions of the brain that are dedicated to or linked with brain regions that process emotion, Neal said.

In a second experiment, Neal and his co-author, Tanya L. Chartrand of Duke University, provided even stronger evidence for the power of “embodiment” of emotions. One group of their subjects had a fast-drying gel slathered on their faces, creating resistance to muscle contractions necessary for the expression of strong emotions. Other subjects got the gel slathered on the inside of an arm, and still another group had the gel smeared on their faces but were asked to detect a person’s emotional state only by listening to his or her voice. The result: Subjects whose facial muscles had to work extra hard to mimic the emotional states of people in photographs were most accurate in perceiving the emotions they were seeing. Subjects whose facial muscles were unaffected by the gel, or who relied only on their auditory perception to interpret another’s emotions, performed no better than usual.