If you thought people who wear glasses are smarter, well, you might be right, according to a University of Edinburgh study.

Does he look intelligent? It’s because of the glasses, isn’t it?

It’s not every day that science gets the chance to address a frivolous stereotype, but here we are. In the largest study of its kind, Scottish researchers analyzed cognitive and genetic data from over 300,000 people aged between 16 and 102. Surprisingly, they found that people who were more intelligent, on average, were more likely to have genes which indicate they will wear glasses. This wasn’t the main focus of the study, but it was an interesting takeaway.

Overall intelligence has long been linked with many health traits, but these correlations are generally positive. Several studies have found that higher cognitive function can be linked to lower incidence of problems such as angina, lung cancer, and depression. More intelligent people generally tend to lead longer, healthier lives — but this is not necessarily a result of the intelligence itself, and is more likely to be a result of the lifestyles intelligent people generally choose to have.

“Some individuals have generally higher cognitive function than others,” researchers write in the study. “These individual differences are quite persistent across the life course from later childhood onwards. Individuals with higher measured general cognitive function tend to live longer and be less deprived.”

With eyesight, however, things seem to be quite different: the genetic correlations between general cognitive function and eyesight were in opposite directions. The team reports that they found that there was a 28% greater chance that people with higher cognitive levels would also need some form of vision correction. In other words, almost a third of people with higher cognitive levels will likely need glasses or contact lenses.

However, it’s important to note that poor eyesight and higher intelligence aren’t directly linked — no causation has been established between the two at all. Furthermore, assessing intelligence simply from DNA is challenging and somewhat subjective. Any missteps can lead people to fall into the unwanted trap of the so-called race science.

But despite the lack of scientific information, there’s plenty of evidence that wearing glasses, whether you need them or not, makes people think you are more intelligent, industrious, and reliable. It goes even further: glasses make people seem more harmless. As lawyer Harvey Slovis explained to New York magazine, glasses make people seem more incapable of a crime, creating a sort of “nerd defense.”

However, maybe it’s time we start looking beyond these prejudices, isn’t it?

Journal Reference: Gail Davies et al. Study of 300,486 individuals identifies 148 independent genetic loci influencing general cognitive function, Nature Communications(2018). DOI: 10.1038/s41467-018-04362-x