“Machine learning and data science are promising but can be seen as a little bit of a religion,” Amaral said. “You still need to test your results. We developed a new method to guide people to solve the clustering problem to test the findings.”
Their algorithm first revealed about 16 personality clusters using traditional clustering methods. The researchers then imposed additional constraints, winnowing down the clusters to four distinct personality types.
“The data came back, and they kept coming up with the same four clusters at higher densities than you’d expect by chance, and you can show by replication that this is statistically unlikely." Revelle said. "The methodology is the main part of the paper’s contribution to science."
To ensure the new clusters of types were accurate, the researchers used a notoriously self-centered group — teenaged boys — to validate their information.
“We know teen boys behave in self-centered ways,” Amaral said. “If the data were correct and sifted for demographics, they would they turn out to be the biggest cluster of people.”
Indeed, young males are overrepresented in the Self-Centered group, while females over 15 years old are vastly underrepresented.
Along with serving as a tool that can help mental health service providers assess for personality types with extreme traits, Amaral said the study’s results could be helpful for hiring managers looking to ensure a potential candidate is a good fit or for people who are dating looking for an appropriate partner.
And good news for parents of teenagers everywhere: as people mature, their personality types often shift. For instance, older people tend to be less neurotic yet more conscientious and agreeable than those under 20 years old.
“When we look at large groups of people, it’s clear there are trends, that some people may be changing some of these characteristics over time," Amaral said. "This could be a subject of future research."
The research was funded by a gift from Mac and Leslie McQuown along with support from Department of Defense Army Research Office, and the National Science Foundation.
Julianne Hill, director of strategic communications at the McCormick School of Engineering, is the author of this story.