In August 2008, the Census Bureau released a report that predicted a seismic shift in American demographics: By 2050, minorities would make up more than 50 percent of the population and become the majority.

When Yale psychologist Jennifer Richeson heard about the report on NPR, she remembers thinking, “This is probably freaking somebody out.”

By “somebody,” she means white people.

Richeson’s studies on interracial interactions had taught her that when people are in the majority, the sense of their race is dormant. But the prospect of being in the minority can suddenly make white identity — and all the historical privilege that comes with it — salient. And, she guessed, the prospect of losing majority status was likely to make people (perhaps unconsciously) uneasy.

“The point is that people who think of themselves as not prejudiced (and liberal) demonstrate these threat effects.”

In other words, she wondered if white people would read the news of a coming “minority majority” shift as a threat, a “threat” powerful enough to change their thoughts and behavior.

In the years since, Richeson has tried to answer this question with a trove of experimental research. What she’s found is both unsettling and crucial to understanding politics in the era of President Donald Trump.

Her research — and the research of many other social scientists studying the rise of Trump, Brexit, and other examples of nationalistic backlash around the world — points to how the politics of inclusion will be challenged in the days ahead.

Perhaps one day social scientists will figure out how to get people of different backgrounds to live among one another and not be afraid. But for now, the perceived “threat” of demographic change is making voters fearful and, in turn, giving power to politicians who implicitly or explicitly stoke that fear. It’s a troubling problem crying out for an answer.

The experiments

After the census report came out, Richeson and Maureen Craig, a graduate student working under her (now a psychology professor at NYU), set up a simple experiment.

First, they had a group of white participants read a bit of text summarizing the census report heralding the minority-majority shift.

The results suggest “a sense of a zero-sum competition between groups is activated”

That was the experimental condition. Then they had a second group of white participants read about demographics as they currently exist.

The first round of results was troubling: White participants who read about demographic change showed greater preference for their own racial groups — they were more likely to respond to statements like “I would rather work alongside people of my same ethnic origin” in the affirmative. The paper, published in Personality and Social Psychology Bulletin, also found that the experiment made white participants feel less warm toward members of other races.

This effect has been replicated in other labs. For instance, a study led by psychologist H. Robert Outten reported nearly identical findings in both Americans and Canadians. Outten’s paper also found that the exposure increased white sympathy for other whites, and increased feeling of fear and anger toward minorities.

The results suggest that “a sense of a zero-sum competition between groups is activated,” Craig tells me. When people hear about the rise of one group, they automatically fear it will mean a decline in their own.

To be clear: It’s wrong to conclude from these studies that deep down, all white people harbor extreme animus. The psychologists do not see it that way. On average, Craig says, people in her studies report tolerant attitudes toward minorities. “We’re saying that there’s a [small] relative difference, and that difference is leading toward more negative attitudes,” she says. The effects they find are small in effect size, but consistent.

“The point is that people who think of themselves as not prejudiced (and liberal) demonstrate these threat effects,” Richeson says.

You can think of the results like this: Fear of outsiders is a chord that can be struck in some of us. Some politicians exploit this, and Trump most certainly did when he said that undocumented Mexican immigrants, refugees, and people from Muslim countries ought to be feared and barred from entering our country.

Fear of demographic change is changing political decision-making

It’s not just racial attitudes that shift when whites are exposed to the demographic data. Political attitudes shift too. And this can, in part, explain why Trump found an audience with his nationalistic rhetoric.

In another paper, published in Psychological Science, Richeson and Craig found that exposure to the census report nudged participants to be more conservative on a variety of policies. What’s interesting here is that the policies weren’t necessarily race-related. Participants became more conservative on topics like affirmative action and immigration, as well as on defense spending and health care reform.

The threat of demographic change — and the loss of status that comes with it — provokes a broad sense of wanting to hunker down. A similar thing happens when psychologists remind people of their mortality. Psychologists find the threat of death makes people more conservative, and more wary of others too.

And it’s not that conservatives are becoming more conservative. White people of all political backgrounds in America become more conservative in these experiments.

But why would a self-avowed liberal change her political position just because of a line from a census report? Richeson and Craig are pretty sure the answer is that these white people feel threatened.

Richeson and Craig ran a version of the experiment where participants were told that even though the minority-majority switch was coming, the social order would continue to be the same. White Americans would still come out on top in American society.

In that condition, the effect disappeared. “And that’s how you know it’s status threat” fueling the effect, Richeson says.

She doesn’t know how that threat will increase or diminish in the population in the coming years. The feeling of threat could even decrease. “People may have seen electing [Trump] as an intervention that will stave off the status and cultural shifts they are concerned about,” she says.

But then, that’s concerning too: We can’t neutralize the threat of demographic change at the cost of minorities.

A sense of demographic threat influences voting behavior, too

What’s compelling about this line of research is that it suggests not only do people change their attitudes, but they also change their behavior in response to demographic threat.

Maria Abascal, a sociologist at Brown University, found in an experiment that white participants who are exposed to information about Hispanic population growth will donate less money to black people. Think about this for a second: When hearing about the rise of one minority group, participants in the study were stingier toward an unrelated minority group. That means the growth in the Hispanic population is causing an anxiety that generalizes into a broad sense that white people’s status needs to be reinforced. (The information about Hispanic population growth did not change the behavior of the black participants in the study.)

And right before the election, a paper led by Brenda Major at UC Santa Barbara found that exposure to demographic change increased support — to a small degree — for Trump (and not the other Republican presidential candidates) among whites who highly identified with their racial groups.

“Among very highly identified Whites ... the racial shift reminder shifted them one point more likely to vote for Trump on a 7 point scale — from about a 2.5 to about a 3.5,” Major explains in an email. “Of course, Democrats were still less positive toward and intended to vote for Trump less than Republicans did, but the group threat pushed them both in that direction. Why Trump and not the other Republican candidates? I think because Trump's rhetoric was and is most hostile toward people who aren't White.”

Outside of psychology labs, there’s compelling evidence that Trump’s win was linked, in part, to white anxiety about a changing world. Racial attitudes were a strong predictor of Trump support in the lead-up to the election. “Republicans who scored highest on racial resentment were about 30 percentage points more likely to support Trump than their more moderate counterparts in the bottom quartile of the party in racial conservatism,” Michael Tester, a UC Irvine political scientist, explained to the Washington Post.

Why increasing diversity could make America a more hostile place

All these results are troubling. And they’re troubling because the forces dividing Americans along racial lines may only grow stronger in the Trump era.

Vox’s Alvin Chang has reported on another disturbing trend: that white America is slowly segregating itself from diverse communities. It’s a story, he writes, about:

... how many white people have reacted to increasing exposure to nonwhite populations, who are following in their footsteps and pursuing the traditional American dream. The reaction is not always articulated or even intentional; in fact, most people say they want to live in a diverse and integrated community; they, too, have the dream that no one will be judged by the color of their skin. But data shows that as minorities move into suburbs, white families are making small and personal decisions that add velocity to the momentum of discrimination. They are increasingly choosing to self-segregate into racially isolated communities.

So as the country diversifies, white Americans are increasingly choosing to live among each other. But demographic change will keep charging ahead. White Americans will learn about the changes, but they won’t have the opportunities to make the intensive face-to-face contact necessarily to assuage their fears.

There’s one study that shows it’s possible to meaningful reduce prejudice in the real world. And for that opinion change to happen, it requires going door to door and having voters talk about their real lived experience, and their own memories of feeling marginalized. It isn’t easy. But with contact, it’s possible.

“My biggest concern about all of this is if we’re going to really build a multiethnic, interfaith democracy, we can’t have these levels of racial polarization”

It’s not just Richeson and Craig who worry that increasing diversity might make America a more hostile, less compassionate place.

“I think that diversity, immigration, and multiculturalism are right at the heart of the sociological problem in Western democracies, along with the new and pernicious role of social media,” psychologist Jonathan Haidt recently told Vox’s Sean Illing. “So long as we are all immersed in a constant stream of unbelievable outrages perpetrated by the other side, I don’t see how we can ever trust each other and work together again.”

Haidt continued:

As multiculturalism is emphasized more and more, there emerges a reaction against it on the right, which is attractive to the authoritarian mind and also appeals to other conservatives. And this, I think, is what has happened, this is what Trump is about — not entirely, of course, but certainly this is a big factor.

Elsewhere, researchers find that mere exposure to marginalized groups of people backfires when it comes to progressive policymaking. A recent study in PNAS (Proceedings of the National Academy of Sciences) found that when experiment participants walked past an actor dressed up like a destitute homeless person, they were less willing to support redistribution of income through a “millionaire’s tax” on a questionnaire. “I do think it could be the case that, for an affluent individual, seeing someone who is poor reminds you of your wealth and perhaps makes you more protective of it,” Melissa Sands, the author of that study, tells me in the email.

The big question the researchers cannot yet answer is this: How does the country keep growing more diverse without these fears coming to an even more dangerous boil?

“My biggest concern about all of this is if we’re going to really build a multiethnic, interfaith democracy, we can’t have these levels of racial polarization,” Richeson says. “We really need to understand the many identity threats that are happening here. Both for White Americans and for the many racial minorities that are feeling very threatened by a Trump presidency, what this means for all kinds of racial progress. … How do we come together given this demographic split? it’s terrifying for us.”

Richeson says she doesn’t have the answers. No one does. But she hopes to look for them in some research projects over the next several years. “If we can understand the mechanism giving rise to what we are seeing in the world, then we can address it,” she says.

In addition to lab studies, Richeson says her colleagues in the field are planning trips out into America, to learn from white people and understand how they feel about demographic change. The goal is to find a way to frame the change in a way that’s nonthreatening, or communicate messages that build multiracial coalitions. (Richeson wonders if poor white voters will better identify with poor black voters when reminded of their shared economic hardships, for instance.)

One last thing to note: The US Census projections are based on arbitrary ideas of race. None of this matters if the census changes its definition of who it considers to be white. For instance, the 2008 report considered biracial people to be part of the coming “minority majority.” If the census redefines what it means to be “white,” then the possibility of a minority majority may go away.

The “threat” is dependent on who you consider part of your team. If the labels change, so may the feelings of threat. “This term ‘majority minority’ has absolutely no meaning,” Richeson says.

Unless we let it.

“It’s horrible that things are devolving as much as they are in terms of intergroup harmony,” Richeson says. “But what that says to me is our work is all the more important.”