Do we really become more bigoted with age? Science suggests yes.

Young people in the United Kingdom were shocked and dismayed when the Brexit vote came in last week. The youth — by a large margin — supported remaining in the European Union. Many of their parents and grandparents did not.

“Brexit is a middle finger from the baby boomers to young people like me,” wrote Jack Lennard, a UK graduate student, in an essay for Vox. “Despite young people having to live with the decision of the referendum for an average of 69 years, it has been decided for them by people who will only have to live with it for an average of 16 years.”

The reasons UK voters decided to leave are complicated. Polling results suggest they were motivated by a combination of nationalist sentiment, a desire for self-determination, and anxiety about immigration, and some might have been aided by misinformation from politicians.

But perhaps Lennard and his generation could one day be more inclined to make a vote similar to the Brexit. Social science tells us that older people tend to be more conservative than the young.

Indeed, Brexit raises a big — and disturbing — question: Are we all destined to become more prejudiced, cantankerous shadows of our former selves one day?

Why older people generally are more conservative

The trouble with answering this question is that it’s hard to separate the generational effects of being born into a particular era of history from the effects of aging. There’s just no longitudinal study tracking political preferences for five decades.

But scientists have found evidence that suggest both effects come into play.

There’s no doubt the era we’re born into matters a lot for forming our worldviews. Americans born in the 1920s grew up in a country where segregation was rampant and same-sex marriage was unthinkable. Americans born in the 1990s have a completely different reference for what’s normal. (There’s data to suggest the world events that happen when we’re around 18 make the most lasting impression on our future voting decisions, at least in the United States. “Generations carry with them the imprint of early political experiences,” a Pew report states.)

So what does the evidence say about what aging itself does to our worldviews?

One clue comes from personality research.

Personality is considered — generally — to be stable across a life span. But a 2011 study on 20,000 Germans found an interesting wrinkle. The older Germans surveyed had decreased levels of openness to new experiences.

That’s important because openness, in particular, “tends to predict liberal attitudes,” Brent Donnellan, a professor of psychology at Texas A&M University and a co-author on that study, tells me in an email.

He stresses that the effect size was small. “If you are pretty liberal as a 40 year old, you will most likely be pretty liberal as a 60 year old,” he writes. But “the absolute level might go down a bit.” You’ll still be a liberal 60-year-old relative to other 60-year-olds, but less liberal compared with a group of 25-year-olds.

The German study was a snapshot at two points in time, not a long-term longitudinal effort. So it can’t say age changed openness outright. But other research finds these age-related changes are the same in different countries, which suggests something fundamental might be at play. A 2009 study compared age, political leanings, and personality in Belgium and Poland (countries with widely different histories post–World War II) and found this same pattern.

One reason for these personality changes may be that as we age, we have an increased “need for closure,” which is the desire to minimize uncertainty and ambiguity.

There’s one big caveat to mention here: Just because older people may tend toward conservatism doesn’t mean they can’t adopt more liberal views.

A 2007 paper in the American Sociological Review compared data from 25 different surveys on social attitudes conducted between 1972 and 2004. What they found was that on social tolerance questions and statements — like should women “take care of running their homes and leave running the country up to men?” and “White people have a right to keep Africans Americans out of their neighborhoods if they want to, and African Americans should respect that right” — older generations grew more tolerant compared with their responses in an earlier era.

Society as a whole may be becoming more tolerant.

Are older people more prone to prejudice than young people?

Bill von Hippel, a psychologist at the University of Queensland in Australia, has found an interesting pattern in his experiments and studies on age and prejudicial opinions.

Von Hippel finds that older adults generally want to be fair and restrain prejudicial thoughts. But they literally just can’t control themselves, which Von Hippel suspects is the result of the deterioration of the brain that comes with aging.

“A lot of research shows that older adults suffer losses in their ability to inhibit unwanted thoughts,” Von Hippel writes me in an email. “We have found that older adults who try to prevent stereotypes from influencing their judgment typically find that they rely on them more and more as they age. … Aging will tend to make many people more negatively disposed toward immigration.”

Here’s his idea. As we grow up, we’re constantly exposed to stereotypes. We can recognize them implicitly, even though we may not believe or act on them. Stereotypes “get activated automatically whether we want them to or not,” he says.

It takes mental effort — the executive control of the frontal lobes — to silence those stereotypes and think of people in a more well-rounded way. As we age, and as our frontal lobes lose their sharpness, we may lose that ability to inhibit stereotypical thoughts, despite our stated intentions.

Von Hippel has demonstrated this in a few experiments. He’s found that older adults show greater levels of racial bias on implicit association tests. Older adults are more likely to remember stereotypical information from stories. And he thinks this is related to other failures of self-control that come with aging — like making inappropriate statements or developing a gambling problem.

“If you are an older adult and know you are going to have an interaction in which it is particularly important not to rely on stereotypes, then best to do so when you are at your most alert,” he tells me. “For most older adults, that means in the morning and some sugar and caffeine don’t hurt either.”

(He also has some unpublished data finding that older people tend to be more argumentative in the afternoon, which suggest their ability to control their thoughts subsides throughout the day.)

We don’t know the extent to which stereotypes about immigrants influenced older Brexit voters. So what’s the takeaway from all this research?

I don’t think it can fully explain the Brexit vote. But I think it can help explain that as we age, we become more susceptible to agreeing with political ideas that offer voters an illusion of control and greater certainty. The Brexit vote was a vote for self-determination, for the UK to make decisions outside of the purview of the EU. That satisfies a need for closure.

It’s important to recognize there are patterns to our thinking that change with age. And though the youth may mock the old for a shortsighted vote now, they should probably realize that, to some degree, they may be heading in that direction themselves.