By Christian Jarrett

When strangers meet, they jump to a lot of conclusions about each other extremely quickly – a process that psychologists call “thin slicing” in reference to the thinness of the evidence upon which such sweeping inferences are made. For instance, being a woman means you’re more likely to be perceived as warm, but less likely to be seen as dominant. If you’re Asian in ethnicity, chances are people will assume you’re less warm but more competent than average. Facial expressions also make an impact – for example, when we smile, we’re seen as more extravert. But what happens when these different influences on first impressions contradict each other? Which comes out on top? A new study in Motivation and Emotion provides tentative evidence that smiles trump cues related to gender and ethnicity. In short, if you smile, you’re probably less likely to be judged by your social identity.

The research team, led by Nicole Senft at Georgetown University, asked 93 undergrad students to look at a series of photographs of faces and for each one to rate the person’s personality based purely on looking at the photograph. The researchers were especially interested in how the students rated the personalities of eight of the faces – two Caucasian men, two Caucasian women, two Japanese men and two Japanese women. The important study manipulation was that half the students looked at these people’s faces photographed showing a neutral expression, and the other half looked at the same faces photographed smiling.

As expected, among the students who rated neutral faces, some of the usual effects of gender and ethnic stereotypes came into play. For example, they rated Caucasian men lower on the trait of agreeableness than Caucasian women, and they rated Japanese women as less extravert than their Caucasian counterparts.

Smiling also had its expected effects in that the same faces were rated as belonging to a more extravert and agreeable person when seen smiling than when bearing a neutral expression.

Most important though was that the influence of the faces’ gender and ethnicity on the students’ personality ratings disappeared or were greatly reduced when those faces were smiling. “Smiling provides cues related to personality that are strong enough to negate the use of information based on gender or race in forming impressions of others,” the researchers said, adding that “smiling levels the playing field”.

It’s worth noting some methodological issues with the study – for instance, there was evidence that individual physical features of the faces (not related to gender, ethnicity or smiling) were influencing the personality impressions, but the research included too few faces to examine what these might be. We also don’t know if similar results would be found for other ethnic groups, or for assumptions based on age or other forms of social identity. Bear in mind too that the smiling faces in this study were displaying genuine smiles so forcing a smile may not have the same effect.

Nonetheless, in some ways these are encouraging results – if you’re the kind of person who smiles a lot, this new research suggests people are more likely to infer your personality from your actual emotional behaviour rather than jumping to stereotypical conclusions about you based on your gender or ethnicity.

—All smiles perceived equally: Facial expressions trump target characteristics in impression formation

Christian Jarrett (@Psych_Writer) is Editor of BPS Research Digest.