That certainly beats the first time I took the IAT. European Americans over African Americans. That was not a good thing to hear, but it’s extremely common—51 percent of online test takers show moderate to strong bias. Faces and words flash on the screen, and you tap a key, as fast as you can, to indicate which category is appropriate.

As words and faces keep flashing by, you struggle not to make too many sorting mistakes. And then suddenly, you have a horrible realization. You think of yourself as a person who strives to be unprejudiced, but you can’t control these split-second reactions. As the milliseconds are being tallied up, you know the tale they’ll tell: When negative words and black faces are paired, you’re a better, faster categorizer. Which suggests that racially biased messages from the culture around you have shaped the very wiring of your brain. We’re not born with racial prejudices. In evolutionary terms, it’s efficient to quickly classify a grizzly bear as dangerous.

The trouble comes when the brain uses similar processes to form negative views about groups of people. But here’s the good news: Research suggests that once we understand the psychological pathways that lead to prejudice, we just might be able to train our brains to go in the opposite direction. Sorting anything from furniture to animals to concepts into different folders inside our brains is something that happens automatically, and it helps us function. In fact, categorization has an evolutionary purpose: Assuming that all mushrooms are poisonous and that all lions want to eat you is a very effective way of coping with your surroundings. Forget being nuanced about nonpoisonous mushrooms and occasionally nonhungry lions—certitude keeps you safe. But a particular way of categorizing can be inaccurate, and those false categories can lead to prejudice and stereotyping. This means that when you think of people in that category, you rapidly or even automatically come up with assumptions about their characteristics.

Essentialism about any group of people is dubious—women are not innately gentle, old people are not inherently feebleminded—and when it comes to race, the idea of deep and fundamental differences has been roundly debunked by scientists. Even people who know that essentializing race is wrong can’t help absorbing the stereotypes that are pervasive in our culture. In polls, for example, few Americans admit holding racist views. But when told to rate the intelligence of various groups, more than half exhibited strong bias against African Americans. Humans are tribal creatures, showing strong bias against those we perceive as different from us and favoritism toward those we perceive as similar. In fact, we humans will divide ourselves into in-groups and out-groups even when the perceived differences between the specific groups are completely arbitrary.

Then participants are randomly sorted into two groups, red or green. In subsequent tasks, people consistently show favoritism toward the arbitrary color group to which they are assigned. In other words, if you give people the slightest push toward behaving tribally, they’ll happily comply. So if race is the basis on which tribes are identified, expect serious problems. One simple evolutionary explanation for our tendency toward tribalism is safety in numbers. You’re more likely to survive an attack from a marauding tribe if you join forces with your buddies.

And primal fear of those not in the in-group also seems closely tied to racial bias. Amodio’s research suggests that one key area associated with prejudice is the amygdala, a small and evolutionarily ancient region in the middle of the brain that is responsible for triggering the notorious fight-or-flight response. Become more interesting every week! We will use your email address to send you this newsletter. And your life’s about to get more interesting. 201d Can You Solve It?

A year is 12 months, 52 weeks, and 365 days. Yet, somehow, 1972 is considered the longest year in history. Here’s what the five major entertainment awards ceremonies looked like before they became the prime-time galas they are today. Frigid temps dragging you down? Let these classic winter weather photos from the Library of Congress archives make you feel glad to be living in the 21st century. No idea what I’m talking about? Get the definitions of 8 weird words here. Let’s just say geography was the last thing on the telephone company’s mind. Are you the type to go hang gliding in Australia or cozy up for a week-long staycation? The answer is in your stars. The reason behind it is actually really sweet. Basically, your brain is working overtime. Can You Solve This Tricky Numbers Riddle in Less Than 60 Seconds?