George Zimmerman followed Trayvon Martin because he perceived him as dangerous. The defense argues he was, the prosecution argues he wasn’t. No one, of course, argues that Zimmerman approached Martin with kindness, or stopped to consider the boy as anything other than suspicious, an outsider. Ultimately Zimmerman shot and killed Martin. A lack of empathy can produce national tragedies. But it also drives quieter, more routine forms of discrimination.

Let’s do a quick experiment. You watch a needle pierce someone’s skin. Do you feel this person’s pain? Does it matter if the person’s skin is white or black?

For many people, race does matter, even if they don’t know it. They feel more empathy when they see white skin pierced than black. This is known as the racial empathy gap. To study it, researchers at the University of Milano-Bicocca showed participants (all of whom were white) video clips of a needle or an eraser touching someone’s skin. They measured participants’ reactions through skin conductance tests—basically whether their hands got sweaty—which reflect activity in the pain matrix of the brain. If we see someone in pain, it triggers the same network in our brains that’s activated when we are hurt. But people do not respond to the pain of others equally. In this experiment, when viewers saw white people receiving a painful stimulus, they responded more dramatically than they did for black people.

The racial empathy gap helps explain disparities in everything from pain management to the criminal justice system. But the problem isn’t just that people disregard the pain of black people. It’s somehow even worse. The problem is that the pain isn’t even felt.

A recent study shows that people, including medical personnel, assume black people feel less pain than white people. The researchers asked participants to rate how much pain they would feel in 18 common scenarios. The participants rated experiences such as stubbing a toe or getting shampoo in their eyes on a four-point scale (where 1 is “not painful” and 4 is “extremely painful”). Then they rated how another person (a randomly assigned photo of an experimental “target”) would feel in the same situations. Sometimes the target was white, sometimes black. In each experiment, the researchers found that white participants, black participants, and nurses and nursing students assumed that blacks felt less pain than whites.

But the researchers did not believe racial prejudice was entirely to blame. After all, black participants also displayed an empathy gap toward other blacks. What could possibly be the explanation for why black people’s pain is underestimated?

It turns out assumptions about what it means to be black—in terms of social status and hardship—may be behind the bias. In additional experiments, the researchers studied participants’ assumptions about adversity and privilege. The more privilege assumed of the target, the more pain the participants perceived. Conversely, the more hardship assumed, the less pain perceived. The researchers concluded that “the present work finds that people assume that, relative to whites, blacks feel less pain because they have faced more hardship.”

This gives us some insight into how racial disparities are created—and how they are sustained. First, there is an underlying belief that there is a single black experience of the world. Because this belief assumes blacks are already hardened by racism, people believe black people are less sensitive to pain. Because they are believed to be less sensitive to pain, black people are forced to endure more pain.

Consider disparities in treatment for pain. We’ve known for at least two decades that minorities, primarily blacks and Hispanics, receive inadequate pain medication. Often this failure comes when people need help the most. For example, an early study of this disparity revealed that minorities with recurrent or metastatic cancer were less likely to have adequate analgesia. Racial disparities in pain management have been recorded in the treatment of migraines and back pain, cancer care in the elderly, and children with orthopedic fractures. A 2008 review of 13 years of national survey data on emergency room visits found that for a pain-related visit, an opioid prescription was more likely for white patients (31 percent) than black patients (23 percent).

Some of the problem is structural. We’ve also known for some time that pharmacies in nonwhite communities fail to adequately stock opioids. In a 2005 study, Michigan pharmacies in white communities were 52 times more likely to sufficiently stock opioids than in nonwhite communities. But this does not fully explain the problem. When pain medicine is available, minorities receive less of it. Medical personnel may care deeply about treating the pain of minorities. Even so, they might recognize less of it—and this may explain why the pain is so poorly treated.

The racial empathy gap is also a problem of our criminal justice system. Consider research on the impact of race on jury decisions. A 2002 experiment showed the power of race, empathy, and punishment. The researchers asked 90 white students to act as jurors and evaluate a larceny case. The manipulation, as you might suspect, is whether the defendant was black or white. But before jurors decided the defendant’s fate, they participated in an “empathy induction task.” Some jurors were assigned to a high-empathy condition and asked to imagine themselves in the defendant’s position. Other jurors were assigned to a low-empathy condition and asked to simply remain objective. Ultimately, the jurors gave black defendants harsher sentences (4.17 years) than whites (3.04 years)—even in the high-empathy condition (3.26 years versus 2.20 years, respectively)—and felt less empathy for black defendants.

This helps explain harsh sentencing in juvenile justice. Nationwide, youth of color are treated more harshly than their white peers. What is a prank for a white student is often treated as a zero-tolerance offense by a minority student. Minority students are more likely to receive an out-of-school suspension, even if they have a disability, more likely to be referred by their schools to law enforcement, more likely to be arrested, more likely to be tried in adult court, and more likely to receive a harsh sentence. Recall that participants assumed blacks felt less pain because of their perceived hardened lives. Stanford University researchers found something similar in juvenile sentences. In Stanford’s study, people perceived black children as more like adults, who deserve severe adult punishment, and not innocent kids, who deserve our empathy and compassion.

If we know part of the problem is a lack of empathy, is it possible to learn empathy and overcome an implicit bias? In the study of jurors, we saw empathy induction did not eliminate the empathy gap. But it did produce somewhat more lenient sentences. Perhaps this is a first step.

The perspective-taking approach seems to help. In a 2011 study, researchers tested whether empathy induction reduced pain treatment disparities. Participants assigned to the perspective-taking group were instructed to “try to imagine how your patient feels about his or her pain and how this pain is affecting his or her life.” As other studies have found, many people exhibited an empathy bias that drives their bias in pain treatment. But this study gives us some hope. It shows that the perspective-taking intervention reduced treatment bias—in this case by 55 percent.

But this approach misses something crucial. Perspective-taking must account for—and eliminate—the assumptions about what it means to be black or a minority in the United States. After all, imagining how pain affects a person’s life will not completely extinguish bias. Part of the problem is how we think about other people’s pain—and how when we stereotype their lives, we don’t.