Yale researchers are the first to show that weight bias extends to the courtroom.

In a study conducted by researchers at the Yale Rudd Center for Food Policy & Obesity, participants given hypothetical court cases were more likely to deem overweight female defendants guilty of a crime over their lean counterparts. The findings call not only for policies to prevent weight bias in the courtroom, but also for the inclusion of weight status as a protected category under anti-discrimination law on the state and federal level, said lead study author and clinical psychology doctoral student Natasha Schvey GRD ’14. The study appears online in the January issue of the International Journal of Obesity.

“We know from decades of research now that weight stigma has been very well-documented in multiple domains, including employment opportunity, health care, education, the media and so on,” Schvey said. “However, we haven’t yet determined whether weight bias may actually be present in the courtroom, so it seemed like a critical gap in the literature that we wanted to explore.”

In the study, conducted online, 471 participants considered the same case of check fraud and were randomly assigned either a lean or obese male or lean or obese female defendant. Using a “5-point Likert scale,” participants then decided the guilt of the accused individual. Schvey found that while male participants assigned significantly more guilt to overweight female defendants than to lean female defendants, they did not assign more guilt to overweight male defendants than lean ones. Females, on the other hand, did not discriminate on the basis of weight for either male or female defendants.

The study did not assess why the participant decided to assign guilt to one group of defendants as opposed to another, but Schvey said there is a common misconception that obese individuals may lack impulse control and that this stereotype may drive the bias.

“We do know that men do tend to endorse greater weight bias than women, so that would potentially explain the direction of the results,” Schvey said.

The finding of stigmatization of overweight females and not males is corroborated by a long line of existing research, study authors added.

Cornell Law professor Sheri Lynn Johnson LAW ’79 said the finding is important because it adds to a large literature suggesting the vulnerability of the criminal justice system to jury bias. The most significant limitation of the study is that it examined only a single type of crime, one that may be closely linked to stereotypes about obesity and thus not provide a generalizable conclusion about weight bias in courts, Johnson said.

“If you had a bank robbery, would you see the same phenomenon? I’m guessing you would not because some of the stereotypes about bank robbery are such that you imagine physical activity and strength,” she added.

In order to mitigate weight bias in trials, Schvey said courts should consider modifying judicial instruction to include text about weight discrimination. Moreover, Schvey said there exists no federal legislation protecting obese individuals from discrimination on the basis of weight, and this study and others documenting the prevalence and consequences of weight-based discrimination indicate the need for protective law.

This finding also adds to a large literature that resists the common misconception that the most impartial jurors are those with the fewest ties to discriminated groups, Johnson said.

“What we do see again and again is that we need more diverse jurors in order to counteract the biases of various groups,” she said.

Schvey said she plans to pursue the finding by comparing the study results to actual juror behavior and court archives.

According to the Centers for Disease Control and Prevention, more than one-third of the adult population in the United States is obese.