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.