US researchers suggest that people who have undergone Botox treatments not only change their appearance but may also have a weakened ability to experience emotions.

Joshua Davis and Ann Senghas, professors of psychology from Barnard College at Columbia University in New York, and colleagues, wrote about their findings in a paper published online in the journal Emotions on 10 June.

Although it has been over a century since William James, an American pioneer of psychology proposed a theory of emotion that stated unless it can be expressed physically in the body it doesn’t really exist, nowadays referred to as the facial feedback hypothesis (FFH), attempts to test it have been inconclusive.

That is until Botox came along, because it paralyzes face muscles used to express emotion (thus reducing wrinkles) and so you can use it to test FFH by comparing its effect with that of a cosmetic filler that does not affect facial muscles: this is essentially what the researchers did.

“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,” Davis told the press, according to a report by UPI.

A person who has received treatment with Botox can respond to an emotional event, for instance a sad scene in a movie, but their facial muscles will be less active, and this sends less feedback to the brain about what the face is expressing.

“It thus allows for a test of whether facial expressions and the sensory feedback from them to the brain can influence our emotions,” explained Davis who said Botox enabled them to design a study where they could “isolate the effects of facial expression and the subsequent sensory feedback to the brain that would follow from other factors, such as intentions relating to one’s expressions and motor commands to make an expression”.

For the study, Davis, Senghas and colleagues examined two groups of participants: one received Botox treatment and the other, the control group, received Restylane, a cosmetic filler that does not paralyze facial muscles.

The participants filled in questionnaires about their emotional experiences to watching positive and negative video clips before and after treatment.

The researchers wrote that results from the Botox group showed no changes between the pre- and post-treatment emotional responses to the most positive and negative video clips, but when they compared the two groups they found that the Botox group showed an overall significant decrease in the strength of emotional experience.

They said these results were due to two effects: a pre- versus post-treatment decrease in responses to mildly positive clips in the Botox group and a surprising increase in responses to negative clips in the control group.

They concluded that:

“These data suggest that feedback from facial expressions is not necessary for emotional experience, but may influence emotional experience in some circumstances.”

The researchers recommend further studies be done to clarify the relationship between expression and experience.

For example, one avenue to explore would be how specific emotions relate to individual muscle groups and how this influences expressions like frowns and smiles.

“The effects of BOTOX injections on emotional experience.”
Davis, Joshua Ian; Senghas, Ann; Brandt, Fredric; Ochsner, Kevin N.
Emotion, Volume 10, Issue 3, June 2010, Pages 433-440
DOI:10.1037/a0018690

Additional source: UPI.

Written by: Catharine Paddock, PhD