Revealed: what your EYES say about you, according to science

They are often described as the ‘windows to the soul’.

But a new study suggests that our eyes may reveal more about us than we previously thought.

Researchers from Leiden University have revealed that our eyes determine how people perceive everything from our attractiveness to our generosity.

While you might think it’s all about color, the researchers found that two other factors are critical: pupil size and the brightness of the iris.

In their study, the team asked people to rate photos of non-human primates with altered eyes.

Their results showed that animals with bright irises and large pupils were rated as more attractive and friendly.

Meanwhile, animals with larger pupils also generated larger charitable donations.

“Our results demonstrate that small changes in perceived eye morphology influence behavior and affective responses,” the researchers said.

In their study, the team asked people to rate photos of non-human primates with altered eyes. Their results showed that animals with bright irises and large pupils were rated as more attractive and friendly

The eye consists of many parts, including the iris (the colored part), the pupil (the opening in the center of the iris), and the lens (the transparent structure in the eye).

Most studies tend to only look at the effects of each of these components separately.

For example, researchers have previously discovered a link between pupil size and friendliness, attractiveness and trustworthiness.

However, in their new research, the team wanted to understand whether changes in both the pupil and the iris affect the way we are judged.

Writing in their study, published in Cognition and emotionThe researchers, led by Juan Olvido Perea-Garcia, explained: ‘Despite the close link between the visibility of the iris and the pupil, the observed effects of the two have largely been studied separately.

‘We show in two experimental studies that the effects of perceived pupil size depend 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 were adapted to pupil size, with some having larger than normal pupils, 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, participants were asked how much money they would donate to a charity to preserve the primate, and how cute, friendly and attractive they found the image.

The results showed that participants donated more when exposed to eyes with larger pupils.

They also rated animals as cuter, friendlier and more attractive if they had larger pupils.

In the second experiment, 121 participants were also shown portraits of non-human primates, but this time, in addition to their pupil size, the brightness of their iris had also been adjusted.

This time, the researchers found 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 crucial for our perception of people, but that the brightness of the iris also plays a role.

“The ratings for both perceived cuteness and friendliness follow the same pattern and strongly suggest that pupil size is the most important factor influencing affective responses,” they said.

‘Bright irises resulted in high cuteness ratings when the pupils were large, but low cuteness ratings when the pupils were constricted.

“Dark irises, which can obscure the perceived size of the pupil, received an average cuteness rating.”