Brown-eyed men seem to be more trustworthy than most blue eyed males, but is it more to do with the shape of the face than the color of the eyes?

In a new study published in PLOS ONE, researchers led by Karel Kleisner from Charles University in the Czech Republic, set out to investigate what dictates a trustworthy face.

Previous research has shown that facial appearance significantly influences various social interactions. Perception of the face gives information on trustworthiness, therefore impacting economic, social, and reproductive success of an individual.

The researchers asked a group of participants to rate the trustworthiness of male and female faces based on two criteria. The first was eye color and the second was face shape.

A large number of subjects found brown-eyed faces more trustworthy than blue, regardless of whether of they were male or female. Rounded faces of men with larger mouths and bigger chins were seen as more trustworthy than narrow ones, however, the shape of a woman’s face did not have much effect on how trusting they appeared to the participants.

Researchers also administered a third test, giving participants pictures of male faces that were exactly the same except for one variation: the color of the eyes. During this test they found both eye colors were considered equally as trustworthy.

They also found that the key to being perceived as trusting did not come from eye color but rather from facial characteristics that are shared by people with brown eyes.

For example, brown eyed men generally have wider mouths with upward-pointing corners, wider chins, bigger eyes and eyebrows closer to each other, characteristics considered masculine and more trustworthy. On the other hand, men with blue eyes tend to make them seem more shifty, sporting smaller eyes and narrow mouths with downward-pointing corners.

The authors commented:

“We concluded that although the brown-eyed faces were perceived as more trustworthy than the blue-eyed ones, it was not brown eye color per se that caused the stronger perception of trustworthiness but rather the facial features associated with brown eyes.”

Women with brown eyes were also viewed as more trustworthy than those with blue eyes, but not at such a significant rate as men.

These findings also cause researchers to question why blue eyes are so prominent in Northern Europe if blue eyed people are at a disadvantage by appearing less dependable or honest.

The authors suggest that it could be the striking color of blue eyes that give those people a benefit in sexual selection, which cancels out the lack of trustworthiness in the face.

Written by Kelly Fitzgerald