The Neurology of Stereotypes

I once attended a polytechnic school where the mascot was an engineer. It was a men’s school, so the image of the mascot was a kind of geeky looking guy. He wore a goofy hat and was always surveying land or harnessing electrical power or some such. It was an unflattering caricature, and meant to be funny in a self-deprecating kind of way.

A lot of students and alumni didn’t like it, though, and the engineer was eventually replaced with a bird. That’s the problem with stereotypes: They contain enough truth to be both humorous and cruel. We all use stereotypes, probably more than we’d care to admit, because they are fast and efficient cognitive shortcuts that save us a lot of time and energy. You probably have a caricature of an engineer in your mind’s eye right now.

Psychologists are very interested in stereotypes, and how the brain processes them. Do we know when we are falling back on a broad caricature, or do we use them automatically, without deliberation or conscious awareness? How do we police our own lazy mental habits to avoid harming others with simplistic stereotypical thinking? Do we know that stereotypes are wrong, yet find them too psychologically tempting to avoid?

Psychologist Wim De Neys of Leuven University, Belgium, decided that the best way to explore these questions was to actually look at the brain in action. Past research has shown that a particular region of the brain’s frontal lobe becomes active when we detect conflict in our thinking—between an easy stereotype, say, and a more reasoned and complex view. But actually overriding stereotypical thinking requires another part of the frontal lobe. De Neys basically wanted see if stereotypical thinking is a detection problem or a self-control problem. To see, he watched these two brain regions during stereotypical thinking, to see what lit up.

He used a classic psychology problem to make people summon up the stereotypes residing in their neurons. Here’s how it works: Say there’s a room with 1000 people in it, and we know that 995 are lawyers and the other five are engineers. We get to meet just one of these people, named Jack, picked randomly from the group. We learn that Jack is 45-years-old and has four children. He has little interest in politics or social issues and is generally conservative. He likes sailing and mathematical puzzles. Is Jack a lawyer, or an engineer?

Well, which is he? Logically, if you use the statistical part of your brain only, the obvious answer is that he’s a lawyer, simply because there are all those lawyers in the room and there’s a better chance of meeting a lawyer in the room than an engineer. But a lot of people immediately say engineer because Jack fits a stereotype. The majority of even highly educated people do this. Others do say lawyer—and so quickly that it seems instantaneous—but the question is whether the brain needs to quash that powerful engineer caricature in order to give the more reasoned response.

De Neys watched volunteers’ brains as they puzzled through this and similar problems. He found (and describes in the May issue of the journal Psychological Science) that the brain’s stereotype detector lit up regardless of whether the subject answered stereotypically or rationally. So apparently we all detect the stereotype and recognize that it is out of sync with reality. But the brain’s inhibition center—the part of the brain that says, “No, I am not falling for that simplistic idea”—lit up only when the subjects actually reasoned that Jack was a lawyer—that is, only when they overrode the stereotype and made a calculation based on probability. Apparently some of us find the ready caricatures too tempting and use them anyway, against our better judgment.

This goes way beyond fairness to engineers. Think about another stereotype, this one the typical lung cancer victim. He’s old, right? That’s at least the stereotype that most teenagers have, and the one they use to justify taking up smoking. Young people don’t die of lung cancer, so smoking must not be risky for the young—all scientific evidence to the contrary notwithstanding. Stereotypes can indeed be cruel and hurtful—even to those who conjure them up.

For more insights into the quirks of human nature, visit “We’re Only Human . . .” at www.psychologicalscience.org/onlyhuman. This blog now also appears in both the print and web editions of Scientific American Mind at www.sciam.com.