Humans perceive familiar faces as looking happier than those faces that are unfamiliar to them, suggest findings of a new study carried out at the Department of Psychology, University of California, San Diego.

Some earlier studies have suggested that a human mind processes familiar faces in a manner distinct from unfamiliar faces and that familiarity with a face confers an advantage in identity recognition.

Researcher Evan Carr of Columbia Business School says their study shows that “familiarity with someone else’s face affects the happiness you perceive in subsequent facial expressions from that person.”

“Our findings suggest that familiarity–just having ‘expertise’ with someone else’s face through repeated exposure–not only influences traditional ratings of liking, attractiveness, etc. but also impacts ‘deeper’ perceptions of the actual emotion you can extract from that person.”

This study was carried out by Carr with colleagues Timothy F. Brady and Piotr Winkielman.

The researchers hypothesized that familiarity with a face might guide our fundamental perceptual processes in a bottom-up fashion, selectively enhancing the positive features of a stimulus. Researchers designed two experiments that examined how people responded to familiar and unfamiliar faces.



The authors’ abstract states: “In Experiment 1, using a paradigm in which subjects’ responses were orthogonal to happiness in order to avoid response biases, we found that faces of individuals who had previously been shown were deemed happier than novel faces. In Experiment 2, we replicated this effect with a rapid “happy or angry” categorization task. Using psychometric function fitting, we found that for subjects to classify a face as happy, they needed less actual happiness to be present in the face if the target was familiar than if it was novel. Critically, our results suggest that familiar faces appear happier than novel faces because familiarity selectively enhances the impact of positive stimulus features.”


Ultimately, the findings underscore how flexible emotion-perception processes are.

“Emotion perception isn’t only the ‘formulaic’ combination of facial features, it also dynamically incorporates cues specific to the individual you’re trying to decode,” says Carr. “Even the judgment of ‘how happy someone looks’ is inherently subjective to some extent, depending on your previous experience with the person along with the type of expression you’re judging.”

The detailed findings of the study have been published in Psychological Science, a journal of the Association for Psychological Science.