During elections, what affects our decision to vote for one politician over another? We’d like to think that it’s an objective assessment of many different factors including their various policies, their values, their record and so on. But in reality, voters are just not that rational.

In the past, studies have shown that people can predict which of two politicians will win an election with reasonable accuracy based on a second-long looks at their faces. With a fleeting glance and little purposeful consideration, people make strong judgments about a candidate’s competence, that can sway their final choices. And they do this in a remarkably child-like way.

They recruited 684 Swiss students and asked them to rate pairs of politicians who had run