Science, Weeklies

The Secrets of a Smile

A study on smiling shows how perceptions of power and status influence one’s likelihood to mimic smiles.

The eyes may be “the window to the soul,” but a smile can reveal a lot about a person, whether he or she is happy, amused or interested ­— friendly, approachable or polite.

A study presented at the annual Society for Neuroscience conference in New Orleans Oct. 17 suggests a smile might reveal more about a person than once thought — it might reveal how that person perceives another person’s social status.

Why Do We Smile?

Smiling — an example of mimicry — is an important mechanism for bonding and conveying nonverbal messages in social interactions.

Evan Carr, a graduate student in the department of psychology at the University of California San Diego and the study’s lead researcher, said that both power and status seem to affect how humans unconsciously use mimicry.

“Mimicry has been shown in a variety of past research in psychology and neuroscience to aid in socially adaptive behaviors,” Carr said in an email interview.

Such socially adaptive behaviors include affiliation, rapport and empathy.

“Power — this feeling of being able to control the actions of others — has been shown to lead to quite different, and sometimes almost opposite, effects,” he said.

These contradicting functions are what led Carr and researchers to investigate the effects self-perceived status and power have on mimicry, he said.

The Study

In the study, Carr and his colleagues analyzed how one’s perception of power and status influenced the likelihood he or she will return smiles.

Using a sample of 55 volunteers, Carr asked participants to respond to videos of both high-status and low-status people, according to the study.

“High-status” subjects consisted of figures such as doctors and business people, according to an article in The Guardian, while “low-status” subjects were characterized as trash collectors or employees of fast food restaurants.

Volunteers were asked to watch brief videos of people with either high- or low-status jobs. People in these clips expressed either a frown or a smile, conveying feelings of either anger or happiness.

While subjects watched these clips, Carr measured the activity of two particular facial muscles — the first was the zygomaticus major, often referred to as the “smiling muscle,” that brings up the corners of the mouth, and the second was the “frowning muscle,” the corrugator supercilii, which furrows the brow, according to the study.

Carr calculated subjects’ reactions using facial electromyography (fEMG), a technique used to measure muscle activity in one’s face. This technique is capable of recording small electrical currents caused by minute muscle movements.

The Results

After analyzing the data, Carr and the other researchers said they concluded that people who consider themselves as more powerful are more likely to mimic the smiles of people whom they perceive to be lower-status. However, these same subjects are less likely to return the smiles of people they consider to be of a higher status or power than they are. Unlike those who perceived themselves as higher status, people of self-perceived lower status, who do not feel particularly powerful, returned smiles almost equally.

Subjects also reacted to frowning in the videos, according to the study. Regardless of each volunteer’s self-perceived power and status, he or she mimicked the frowns of high-status people more often than the frowns of low-status people.

The study reported two major findings, the first being that feelings of high- and low-power lead to different and distinct changes in facial mimicry. The second is that these effects are influenced by the perceived status of the “mimicry target.”

This research established that there is, in fact, a relationship between power and mimicry.

Deborah Belle, a psychology professor at Boston University, said that power discrepancies play a tremendous role in society.

“Power is often reflected in nonverbal behavior,” she said.

She said smiling is an example of these non-verbal behaviors.

Belle said there are many different functions of smiling. It can convey multiple emotions and feelings.

“[Smiling] can manipulate people’s sense of power,” she said. “Being induced to feel temporarily powerful prompts you to smile more at low-status people.”

The Effects of Smiling

Psychologists often characterize smiles into one of two categories — the Duchenne smile and the non-Duchenne smile, according to the American Psychological Association. The Duchenne smile is a genuine smile that signifies true pleasure and enjoyment. The non-Duchenne smile, however, is a “fake” smile. It is used solely to satisfy others and does not bring one true enjoyment.

There is one major difference between the Duchenne smile and non-Duchenne smile. The Duchenne smile involves the use of the muscles around the eyes while the non-Duchenne smile does not.

Carr said he and researchers did not measure muscle movement around the eyes, making it difficult to determine whether the responsive smiles in the study were genuine or “fake.”

“We cannot make 100-percent accurate predictions as to why the muscle was recruited,” Carr said. “Our results only speak to the fact that that pattern of muscle activation did occur. We cannot tell, or even make certain predictions about, the ‘why’ behind it.”

Duchenne smiling has more than an important social function, according to an article in the article. It also has a physiological one. Duchenne smiling releases chemicals within the body that boost immunity, reduce stress and lower blood pressure and heart rate.

“Sometimes just a smile can make your entire day,” said Sam Green, a junior in Boston University’s College of Communication. “I can definitely see how simply smiling can reduce anxiety and improve overall happiness.”

However, Carr said that it is difficult to determine health effects based on this study.

“It is hard to generalize these results to overall health and well-being because our experiment looks at very ‘low-level’ effects in a controlled environment,” Carr said. “‘Health’ is influenced by hundreds of other factors.”


A BU Interpretation

From the results in the study, researchers will continue to formulate questions for research regarding emotion, relationships and social hierarchies.

“It is very important to note that we must be cautious of over-interpretation,” Carr said. “Many people want to make overblown or presumptuous claims about why our corrugator would react more intensely to high-status targets, or why powerful people wouldn’t smile back at high-flyers.”

From an anthropological point of view, Eric Kelley, an anthropology professor, said there are other factors that may influence how volunteers reacted to certain images.

“There is a lot of variation,” he said. “Different people may have different reactions.”

He said that aside from social class, factors such as the gender, race and ethnicity of both the volunteer and the subject in the video could influence smiling.

“I find [the results] surprising only because sometimes you’ll smile at people of higher status to gain an advantage.”

He said an example of this would be if he wanted to become acquainted with a more prestigious professor.

“I might smile at them to get them to notice me,” he said.

BU students have their own theories as to why this occurs.

“I think people don’t smile at people of higher status maybe because they’re intimidated by them,” said Kaila Cappello, a senior in the College of Engineering.

Rima Butto, a junior in COM, agrees with Cappello that intimidation may play a role. However, she has a different idea about why high-status people smile at low-status individuals.

“Assuming this is an unconscious thing, maybe they do it to make people of a perceived lower-status to make them feel better about themselves,” Butto said.

Regardless of these theories, Butto said she will think twice the next time a stranger smiles at her on the street.

“I may be a little more perplexed when I think about who exactly is smiling at me and why they’re doing it,” she said.

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