Around 150 years ago, the Italian, Cesare Lombroso, wrote a book on what he called the “Criminal Man.” In this book, Lombroso described ways in which we can identify criminals based on their outward appearance. Take a careful look at someone’s face, and you can see whether they are a born criminal—or at least that’s what he claimed. His ideas were very influential at the time.

Today, though, they might seem ridiculous. But it has taken decades of research to debunk the claims of Lombroso and fellow physiognomists who insisted that we can understand a person’s character with only a careful analysis of his or her face. Nowadays, Lombroso’s “theory” is banished from courtrooms. However, this does not mean that your physical appearance might not influence your chances if you were on trial.

Numerous studies have shown that people form first impressions very quickly. A brief glance at a person’s face is enough for us to form an impression of how trustworthy or competent they are. Not surprisingly, these first impressions are usually not accurate. Even so, research shows that they influence many important decisions including who we want to date, hire, or vote for.

In our studies, we examined whether first impressions also have an impact on who is found guilty in court. We showed research participants case files and asked them to carefully consider the evidence and then reach a verdict. They could rule in favor of the plaintiff or the defendant, depending on who presented the more convincing evidence. Crucially, we showed participants different mug shots of defendants in order to test whether participants would be influenced by their first impressions. To create these mug shots, we used photographs of White men, changing their facial features with computer software. We created one version of each photo in which the person looked particularly untrustworthy and one version in which he looked particularly trustworthy.

Our results clearly showed that facial appearance mattered. Across three studies, we found that defendants whose faces looked untrustworthy were found guilty more often than defendants who looked trustworthy.

But we didn’t stop there. Our main goal was to find out whether we could help people overcome the sway of their first impressions. Could we get participants to make decisions about guilt and innocence that are not biased by the defendants’ appearance? We created two types of interventions that were designed to eliminate -- or at least reduce -- the influence of first impressions on sentencing decisions.

One reason why first impressions are so powerful is that many people erroneously believe that they are actually accurate. That is, many people overestimate their ability to judge how trustworthy someone is just from looking at their face. So, in our first intervention study, we taught participants about this misconception—with some success. After reading about how inaccurate and misleading first impressions actually are, participants were more skeptical about their ability to judge people based on their faces. However, when participants made their sentencing decisions shortly afterward, they were still influenced by the defendant’s appearance. Our intervention was not successful.

So, we tried a different approach.  We know that first impressions come to mind very easily. We also know that people often like to rely on information that comes to mind easily because then they don’t have to spend a lot of time and mental effort on their decisions. They can just go with their gut.  So maybe, if we force participants to deliberate more, they will stop relying on their first impressions. This is what we tried in our second intervention study. We made our participants study the case files very carefully. They could indicate their verdict only after deliberating for a while. But again, this did not produce the desired outcome: Defendants who merely looked untrustworthy were still more likely to receive a guilty verdict.

So what do these results tell us? Even though Lombroso’s theory of the “Criminal Man” has been debunked for a long time, appearances still matter in the courtroom. Our studies suggest that sentencing decisions are influenced by how trustworthy defendants appear to be at first glance. So, people who are unfortunate enough to be born with a facial appearance that makes them look untrustworthy have a higher chance of being found guilty.

To make matters worse, people apparently have great difficulty overcoming this bias. Even when we educated participants about their bias or made them think more carefully about their decisions, they were still swayed by the defendant’s appearance when reaching their verdicts.

At the moment, we are still testing whether other interventions might be more successful. But our current results point to a very important message: We should not underestimate the influence of first impressions when we make decisions about people.

For further reading

Jaeger, B., Todorov, A. T., Evans, A. M., & van Beest, I. (2020). Can we reduce facial biases? Persistent effects of facial trustworthiness on sentencing decisions. Journal of Experimental Social Psychology, 104004.

Jaeger, B., Evans, A. M., Stel, M., & van Beest, I. (2019). Explaining the persistent influence of facial cues in social decision-making. Journal of Experimental Psychology: General, 148(6), 1008-1021.

Bastian Jaeger is an Assistant Professor at Tilburg University. He studies how we form first impressions of others, how accurate our first impressions are, and how they guide our behavior.