They’re often described as the ‘windows to the soul’.
But a new study suggests that our eyes can convey more about us than we previously thought.
Researchers from Leiden University have revealed that our eyes shape how people perceive everything from our attractiveness to our generosity.
While you might think that it all comes down to colour, the researchers found that two other factors are key – pupil size, and iris brightness.
In their study, the team asked people to rate photos of non-human primates with altered eyes.
Their results revealed that animals with bright irises and large pupils were rated as more attractive and more friendly.
Meanwhile, animals with larger pupils also elicited greater charitable donations.
‘Our results demonstrate that small changes in perceived eye morphology impact behaviour and affective responses,’ the researchers said.
Researchers from Leiden University have revealed that our eyes shape how people perceive everything from our attractiveness to our generosity (stock image)
In their study, the team asked people to rate photos of non-human primates with altered eyes. Their results revealed that animals with bright irises and large pupils were rated as more attractive and more friendly
The eye has many parts, including the iris (the coloured part), the pupil (the opening in the middle of the iris), and the lens (the transparent structure inside the eye).
Most studies have tended to only look at the effects of each of these parts on their own.
For example, researchers have previously discovered a link between pupil size and friendliness, attractiveness, and trustworthiness.
However, in their new study, the team set out to understand whether changes to both the pupil and iris influence how we’re judged.
Writing in their study, published in Cognition and Emotion, the researchers, led by Juan Olvido Perea-Garcia, explained: ‘Despite the tight link between the visibility of the iris and pupil, the perceived effects of these two have been studied largely in isolation.
‘We demonstrate, across two experimental studies, that the effects of perceived pupil size are dependent on the visibility of the iris.’
In the first experiment, 64 participants were shown portraits of 32 different non-human primate species, including chimpanzees, Golden-lion Tamarins, and Silvery Gibbons.
The animals’ eyes had been adjusted for pupil size, with some given larger pupils than usual, and others smaller.
Participants donated more when exposed to eyes with brighter irises. They also perceived primates with brighter irises as cuter, friendlier, and more attractive – but only if they had dilated pupils
For each image, the participants were asked to how much money they would donate to charity to preserve the primate, as well as how cute, friendly, and attractive they rated them.
The results revealed that participants donated more when exposed to eyes with larger pupils.
They also rated animals as cuter, friendlier, and more attractive when they had bigger pupils.
In the second experiment, 121 participants were also shown portraits of non-human primates, but this time their iris brightness had been adjusted, in addition to their pupil size.
This time, the researchers fround that participants donated more when exposed to eyes with brighter irises.
They also perceived primates with brighter irises as cuter, friendlier, and more attractive – but only if they had dilated pupils.
According to the researchers, the findings suggest that pupil size is key in our perception of people – but that iris brightness also plays a role.
‘The ratings for both perceived cuteness and friendliness follow the same pattern and strongly suggest that pupil size is the main factor influencing affective responses,’ they said.
‘Namely, bright irises resulted in high cuteness ratings when pupils were large, but low cuteness ratings when pupils were constricted.
‘Dark irises, that may obscure the perceived size of the pupil, received intermediate cuteness ratings.’
