Narcissists, who believe that they are better than their peers, are often colloquially described as big-headed. But do people with over-sized egos really think they have heads to match?
It might sound like an odd question, but there’s good reason to suspect that big-headedness is not just figurative but literal. There is a lay belief that brain volume and head circumference are related to intelligence (recent research suggests that this belief may have a basis in fact), and narcissistic people think they are more intelligent than others.
Minna Lyons, a former winner of the Ig Nobel Prize, an award for research that “first makes people laugh, and then makes them think,” ran a study to find out if narcissism is linked to estimates of head size. Along with her colleagues from the Universities of Liverpool and Sunderland, Lyons recruited over 300 male and female volunteers. The volunteers were asked to estimate the size of five body parts: head circumference, hand size (length from the tip of the middle finger to the wrist), heart weight, brain weight, and lung capacity. As few people have a frame of reference for what constitutes an average head circumference, heart size, and so on, the researchers provided sex-specific population averages.
The volunteers also completed the Narcissistic Personality Inventory, a 40-question survey that measures a person’s narcissism.
Lyons found that men who scored high in narcissism tended to estimate that their head circumference and brain weight were larger than did men who were lower in narcissism. Narcissistic women tended to think their lung capacity was higher. Estimates of the size of other body parts were unrelated to overall narcissism.
Previous research has found that male narcissists are more prone to exaggerate their intelligence than female narcissists, which may explain why the effect of narcissism on estimates of head circumference and brain volume was present in men but not women.
Another possibility is that, because smallness is associated with attractiveness in women, female narcissists, who usually believe they are more attractive than their peers, may have been motivated to underestimate their head size.
The researchers speculate that narcissistic women may have inflated estimates of their lung capacity because this trait is related to fitness, which is a trait that narcissists are known to care about (although it remains unclear why male narcissists didn’t exaggerate lung capacity).
The study was conducted over the internet, and so objective measures of head size couldn’t be collected. The researchers suggest that, in future research, the head circumference of the volunteers should be measured to see how it compares to estimates. Thankfully, they do not suggest that the volunteers’ brains should be weighed.
Lyons won the 2014 Ig Nobel Prize for Psychology, along with her collaborators Peter Jonason and Amy Jones, for their research showing that night owls tend to be more Machiavellian, psychopathic, and narcissistic than people who prefer to go to bed earlier.
Disclaimer: I have previously collaborated with Minna Lyons, though on different projects. My BSc thesis was supervised by another author on the paper, Marco Bertamini.
Lyons, M., Blinkhorn, V., Collier, E. S., & Bertamini, M. (2019). Mine is bigger than yours! Narcissism predicts biases in perceived head size. Studia Psychologica, 61(4), 245–257. doi:10.21909/sp.2019.04.786