You might think that if you were to sit on a jury for a murder trial, you'd be a fair and impartial judge of the facts. But new research suggests that just the way an accused killer's face looks could inform whether you think he or she is guilty or innocent -- and what punishment you think he or she deserves.
A new study published earlier this month in the journal Psychological Science found that facial trustworthiness is a very strong predictor of the sentence that a prisoner receives. According to the research, murderers with less trustworthy faces are significantly more likely to be sentenced to death, while those with more trustworthy faces are likely to be given the milder sentence of life in prison.
Snap Judgments
Previous research has found that we make judgments about people's character almost immediately after looking at their faces.
How do we decide whether a face is trustworthy? It has to do with the emotion that their facial expression conveys.
"Perceptions of trustworthiness are guided in part by the resemblance of a face to an emotion," University of Toronto social psychologist Dr. John Wilson, the study's lead author, told The Huffington Post in an email. "The more your neutral face resembles a positive emotion, the more likely you are to be seen as trustworthy, and vice versa for negative emotions."
So, if the person's mouth turns slightly up at the sides, we'll likely judge them to be more trustworthy. But if their lips curl downwards, resembling a frown or a scowl, we'll perceive them to be less trustworthy.
Our brains use these biases as a sort of shortcut to deciding how (and whether) to interact with people. It's a product of evolution.
"We perceive others in the service of action -- our perceptions of other people and their faces guide our behavior toward them," Wilson explained.
Faulty Convictions
These biases can have some serious real-world implications, particularly in a courtroom setting.
To determine what role facial biases play in legal proceedings, Wilson and hs colleagues collected 700 mug shots of white and African-American convicted murderers (both male and female) in Florida, one of the few states that still has the death penalty. Then, they asked 208 study participants to view 100 of the photos and rate the person's trustworthiness on a scale of 1 to 8. The participants were not given any information about the prisoner's crimes or sentences.
The researchers then compared the convicts' trustworthiness scores with the actual sentences that the killers received. They found that the convicts with faces judged to be untrustworthy received harsher punishments, irrespective of race and gender.
A second experiment offered the same conclusion. The researchers did the same thing with photos and participants' ratings, but this time, they used only photos of men who had been wrongfully convicted of murder and later absolved. The analysis revealed that men with more trustworthy faces were more likely to be exonerated.
Making Better Judgments
Besides having no bearing on the actual evidence in a case, perceptions of trustworthiness tend to be an overgeneralization and are often inaccurate, according to Wilson.
Our facial biases can undermine the fairness of life-or-death decisions. So what can we do about it?
Wilson hopes that the research will help people to understand the biases in their own perceptions of others. Awareness, he says, is the first step.
"Members of juries should be aware of how impressions of defendants’ appearance can impact even the most important judgments that they make," Wilson said.