Eyes don’t lie: children preferably cooperate with partners that have white sclera

Author: Casper Pachocki

In a very recent publication by three scientists (first-authored by a researcher from Utrecht University), the willingness of 5-year-old children to work with faces that have different types of eyes was evaluated. Interestingly, the colour of the sclera (the area around your irises) has a major role for determining children’s willingness to work together. 

So, what does the appearance of your eyes have to do with whether you choose to collaborate with another? The so-called cooperative eye hypothesis, first described in 2002, explains that by having eyes from which you can discern where you are looking at, interactions between individuals to coordinate their behaviour and mental states is eased. 

Previously, it has been confirmed that tracking others’ gaze plays a pivotal role in social development, as it promotes cultural learning, communication, social bonding, and more. Having white sclera makes it easier to track eye movement, and children’s sensitivity towards white sclera has already been demonstrated. However, the actual preference to work with partners with white sclera over dark sclera has not been researched before. 

By utilising videos and pictures of computer-generated 3D human faces with either white sclera, dark sclera, or enlarged irises, Wolf et al. examined the preferences of 48 5-year-olds to work with the presented partners in one of their studies. By asking questions like: ‘’Which one would you ask to help you with your jacket?’’, but also: ‘’Which one looks the cutest?’’, it was found that children perceive as cuter and preferably work with human faces with white sclera. Between faces with dark sclera and enlarged irises, no differences in cooperativeness or cuteness were found. 

Still, it is hard to say whether the children based their choices just on the ability to track gaze in faces with white sclera. For example, white sclera may indicate youth and health, while dark sclera invoke negative feelings not linked to the inability to track gaze. In another experiment, the researchers used similar methodologies, but used faces that had an alien-like blue skin tone. Here, no differences between white sclera and enlarged irises were found. It might be that cooperativeness therefore depends on the human morphology of the face as a whole.  

At first sight, the scientific value of this study might not be entirely clear, while such research can be beneficial. Studies like these greatly contribute to understanding not only the biological development of our eyes, but also how our species socially evolved to what we are today.