People with brown eyes appear more trustworthy than those with blue eyes, according to a new study published by PLOS ONE from researchers of Charles University in the Czech Republic.
People instinctively judge one another by their face and determine if that person is angry, happy, friendly or trustworthy. It's been proven that the amygdala, a structure in the brain, automatically evaluates a person's trustworthiness since people with a damaged amygdala lose their ability to do this. While facial structure has previously been studied, no one has looked at the impact of eye color on trustworthiness.
In this study 238 participants rated pictures of 80 students (40 blue-eyed males and females and 40 brown-eyed males and females) for trustworthiness.
Researchers found that female faces appear more trustworthy than male faces, and people with brown eyes, whether male or female, appear to be significantly more trustworthy then people with blue eyes, except if the blue eyes belong to a broad-faced man.
The shape of the face was also taken into consideration. Researchers found that males with rounded faces, bigger mouths and larger chins were seen as more trustworthy. Face shape did not change the outcome for females.
To determine whether eye color or face shape ultimately influences perceived trustworthiness, researchers created a third test with 106 different raters who looked at the same pictures, except this time the pictures were manipulated to have a different eye color. This experiment showed there was no difference in people with blue or brown eyes.
While brown eyes don't make a person appear more trustworthy, the facial features associated with brown eyes do. A previous study showed that eye color affects the shape of a male face:
Blue-eyed male faces were characterized by a more angular and prominent lower face, a longer chin, a narrower mouth with downward pointing corners, relatively smaller eyes, and rather distant eyebrows. This was also the pattern of an untrustworthy face. In contrast, brown-eyed faces tended to have a rounder and broader chin, a broader mouth with upward-pointing corners, relatively bigger eyes, and eyebrows closer to each other. This was also the pattern of a trustworthy face.
Below is a visualization of the different face shapes and how they relate to eye color and trustworthiness. The female face shape for trustworthiness is not pictured because their shape didn't effect their perception. A - blue eyed female, B - average female, C - brown eyed female, D - blue eyed male, E - average male, F - brown eyed male, G - untrustworthy-looking, H - average man, I - trustworthy-looking male.
