Bias in the Courtroom

In the wake of a recent high-profile case, a Tufts psychologist weighs in on the role that bias plays in jury decisions

A scale of justice, weighed down, in an empty courtroom. In the wake of a recent high-profile case, a Tufts psychologist weighs in on the role that bias plays in jury decisions.

In 2018, off-duty Texas police officer Amber Guyger entered an apartment that she thought was her own, and shot and killed the apartment’s resident, Botham Jean. A jury recently convicted Guyger, who is white, of the murder of Jean, who is black, but sentenced her to a relatively lenient ten years in prison.

How might perceptions of this case have changed if a black man mistakenly killed a white woman in her own apartment? Might the jury’s sentence have been different?

Tufts Now recently spoke with psychology department professor and chair Sam Sommers, author of Situations Matter: Understanding How Context Transforms Your World, about this case and others like it. Sommers is an expert on implicit and explicit racial bias, particularly how it impacts juries, and has testified in multiple court cases on how jury bias can shape verdicts and sentencing.

“Even among individuals who view themselves as fair-minded and egalitarian, more subtle and less conscious forms of bias are pervasive,” said Sommers. “This is true among jurors as well.”

Tufts Now: How does racial bias affect jurors and impact their decisions? Is there a marked difference between explicit bias and implicit bias? 

Sam Sommers: On a daily basis, expectations,

Sam SommersSam Sommers
biases, and prejudices influence the way we see the world. They color our perceptions, judgments, and decision-making processes. Alas, nothing magical happens when people enter a courthouse to serve as jurors—those biases come through the doors with us. 

Racial bias—and a variety of other biases—can influence the impressions we form of the parties and witnesses in a trial, much as they influence how we see neighbors, colleagues, politicians, and other people in the news.

Sometimes that bias can be explicit and conscious, as when we say, “I don’t like people like this”—it can take the form of blatant acts of discrimination or even hate. But even among individuals who view themselves as fair-minded and egalitarian, more subtle and less conscious forms of bias are also pervasive. This is true among jurors as well.

In your research, have you found any changes in juror racial bias over the past twenty-five years—has it lessened, increased, or remained unchanged?

Norms and mores regarding racial bias evolve in a society, for sure. Just five years ago, some went so far as to suggest that we were nearing a colorblind or “post-racial” society. The environment feels very different today, with a nationwide spike in hate crimes. Racial biases among jurors evolve as well.

I once testified in the post-trial review of a trial from the 1980s in which jurors had been overhead using racial epithets in talking about the defendant while on lunch break at the courthouse. I’d like to think such circumstances would be less likely to occur today, though I’m not naive enough to believe they never do.

But even without such blatant language, biases persist.  Ask yourself, in the recent Amber Guyger trial, where a white police officer was convicted of shooting Botham Jean, her black neighbor, in his own apartment: how would this set of facts be viewed differently if a black man had mistakenly entered the apartment of a white neighbor and then fatally shot her?

Does the racial makeup of a jury matter?

Yes. Research indicates that a jury’s racial composition can influence its decision-making processes and its final decision. All-white juries are more likely to convict minority defendants than are racially-diverse juries, for example.

In research that I’ve conducted, we find that jury deliberations tend to be more thorough, with a broader range of perspectives considered, when a jury is racially diverse versus homogeneous. Over fifty years ago, U.S. Supreme Court Justice Thurgood Marshall wrote that a lack of diversity “deprives the jury of a perspective of human events that may have unsuspected importance in any case that may be presented.” Research suggests that he was right.

Are juries diverse enough now? What determines whether or not a jury looks like the community from which its drawn?

Unfortunately, there are a number of obstacles to jury diversity. Contrary to what some people assume, there is no requirement that any particular jury be representative of its community. The requirement is that the jury pool—the group of people called to the courthouse for jury duty—has to look like the surrounding community.

Different regions of the country assemble these jury pools differently. Some base them on lists of voter registrations or driver’s licenses or utility bills, and not every facet of society is represented equally by such lists. Then once jury selection begins, attorneys can use their challenges to remove prospective jurors from the jury panel.

Although the Supreme Court has prohibited such challenges based on race, research indicates that race still plays a role in jury selection. When attorneys try to select a jury that will be most sympathetic to their side of the case, they often take into consideration—consciously or otherwise—a prospective juror’s race.

What can prosecutors, defense attorneys, and judges do to discourage jurors from acting on their biases, explicit and implicit?

Attorneys and judges can try to warn jurors as early as jury selection that their role requires them to avoid any form of prejudice or bias. Making implicit biases more explicit can be one way to combat them. But I’m making this sound much easier than it is— there is no magic cure for juror bias.

To be fair, the real question is how to make everyone in the system aware of and on the lookout for both individual and institutional forms of bias. Everyone—from police to judges to attorneys. Bias in the courtroom doesn’t only come at the level of the jury.

Some trials are decided only by the judge; do you see racial bias occurring in those bench cases, and if so, do they differ from jury cases?

Judges are human, too. One of the arguments in favor of the jury system has always been that twelve heads will be better than one—that with a group making the decision, we might be more likely to avoid the biases of any one, idiosyncratic individual. Of course, on the other side of the coin, judges are trained professionals who see many, many trials and defendants, and so we would hope this training and experience might help curb biases, or at least remind judges to take action to minimize the impact of biases. But judges are people, too, and research indicates that they are susceptible to similar forms of bias.

Robin Smyton can be reached at

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