Average Joes and plain Janes most trustworthy

Average-looking faces may not be considered very attractive, but they are seen as most trustworthy, a new study has found.
"Face typicality likely indicates familiarity and cultural affiliation - as such, these findings have important implications for understanding social perception, including cross-cultural perceptions and interactions," lead researcher Carmel Sofer of Princeton University and Radboud University Nijmegen in the Netherlands said.
Sofer and colleagues wondered whether typicality might be more directly tied to perceptions of trustworthiness.
In one experiment, the researchers created a "typical" face by digitally averaging 92 female faces, and they also created an "attractive" face by averaging the 12 most attractive faces from another set of faces.

They then combined the two faces into one and created nine variations that had differing levels of attractiveness and typicality.
The final result was a continuum of 11 faces that ranged from least attractive to most attractive, with the most typical face occupying the midpoint.

Female participants viewed these face variations and used a 9-point scale to rate them on either trustworthiness or attractiveness; over the course of the study, the participants saw and rated each face three times.
The researchers only included female participants so as to eliminate potential cross-gender differences in how people perceive and evaluate faces.
The resulting ratings showed a sort of U-shaped relationship between face typicality and trustworthiness: The closer a face was to the most typical face, the more trustworthy it was considered to be.

When it came to attractiveness, however, typicality did not seem to play a role - participants rated faces as increasingly more attractive beyond the midpoint of the most typical face.
"Although face typicality did not matter for attractiveness judgements, it mattered a great deal for trustworthiness judgements," Sofer said.
"This effect may have been overlooked, because trustworthiness and attractiveness judgements are generally highly correlated in research," said Sofer.
Another experiment confirmed these findings, showing the relationship between averageness and trustworthiness was not driven by the specific faces used or the by the transformation process that the researchers had employed to digitally combine and alter the faces.

The findings are published in the journal Psychological Science.