New research sheds light on deeply ingrained implicit bias around race, even among those who hold explicitly egalitarian beliefs.

Participants in psychological tests had an easier time identifying people at the top end of their country’s racial hierarchy as human, according to an article research published Monday in the Proceedings of the National Academy of Sciences.

“Contemporary humans who belong to a socially dominant group are not freed from the belief that their group is more human than others,” the researchers wrote.

The research “demonstrates in a really stark way the continued dissociation between beliefs that people explicitly hold — and the sorts of mental associations that reside in our mind,” lead author Kirsten Morehouse, a psychology Ph.D candidate at Harvard University, told The Hill.

The researchers examined 61,000 people over a series of experiments determining how quickly participants could categorize an image as human or nonhuman.

This variant of a well-established psychological study called an implicit association test seeks to uncover the subconscious architecture of thought by assessing how quickly participants can separate categories.

“We can use [decision] time as a measurement of basic things that are inside people’s heads,” Morehouse said.

Past psychology experiments have shown that the length people take to perform a sorting task corresponds to how hard it is psychologically — creating an indirect means for uncovering bias and stereotypes.

In the first rounds of the Harvard study published Monday, participants were shown a series of images that included humans of varying races intermixed with images of animals.

On some of the tests, “White” and “Animal” were on one side of the screen, and “Black” and “Human” were on the other — and on others, the position of the races were reversed. (Click here to try the study.)

If there a participant had a consistent difference in response time with one of the pairings — if they answered faster or slower when “White” and “Human” were on the same side of the screen — it suggested to the scientists that the participant was straining to hold an association between one of the pairs.

In those experiments — the majority of which were carried out among Americans — white participants had an easier time associating the category “human” with white.

Members of other races didn’t share that same bias toward their own group. Black Americans, for example, picked white and Black faces as “human” with equal speed.

But when asked to perform the same test with, say, whites versus Asian-Americans, Black Americans showed the same bias toward white people. So did members of other American minority groups.

Those biases — which in the American cohort were strongest among white people — flew in the face of the values that participants explicitly espoused.

About 96 percent of participants had explicitly rejected the statement — a riff on a famous line from George Orwell’s “Animal Farm” — that some races were more equal than others.

They also were culturally specific. A small side study of East Asians living in East Asia found that they were more likely to see Asian faces as human — while Asian-Americans living in the United States exhibited the same bias towards white faces as other Americans.

The findings, which relied on small differences in how quickly the participant could sort an image, might not make much difference in situations where people have time to stop and consider.

But with a long history of psychological data showing that split-second decisions tend to be made based on intuition and stereotype, they have stark implications for police and other first responders.

“There are just subtle ways where we seem to be stripping the humanity of people — because it’s hard for me to understand how you could see someone as fully human and be able to use really harsh acts of violence,” Morehouse said.

The Harvard study builds on a foundation of other research that suggests that racial stereotyping is a habit that ties in with implicit policy beliefs.

Following the near-fatal 1991 beating of Rodney King by four Los Angeles Police Department (LAPD) officers, reporters combing through court documents found that the LAPD used an internal code “NHI” — for “No Human Involved” — for incidents involving young black men.

In one stark 2008 study in the Journal of Personality and Social Psychology, the authors “demonstrate that U.S. citizens implicitly associate Blacks and apes,” and that those who made that association tended to also more readily endorse violence against black suspects.

“Blacks who are convicted of capital crimes are more likely to contain ape-relevant language than news articles written about White convicts. Moreover, those who are implicitly portrayed as more apelike in these articles are more likely to be executed by the state than those who are not,” those authors found.

And a 2015 study found that people across cultures tend to see members of nondominant racial groups as “less evolved” — a form of dehumanization that surges “after incidents of real intergroup violence” such as the Boston Marathon bombings.

That belief too “strongly predicts support for aggressive actions like torture and retaliatory violence,” the authors found.

Other studies have found that members of some groups have an easier time associating human-linked emotions — such as grief — with their own groups than with others.

At first, the Harvard team hypothesized that, based on historic stereotypes, participants might have more difficulty (and therefore a slower response time) on tests where they had to distinguish between humans and animals.

This turned out to be true on a level beyond what they had expected.

The team found that “the strength of the effect was just so consistent, regardless of how we were representing the animal. We tried representing animals in terms of, you know, friendly pets versus vermin, versus farm animals, versus using these words like beasts and brute,” Morehouse said.

“And so this kind of got us thinking, is the fact that we’re seeing so much stability actually, because what we’re measuring is not really human versus animal — it’s human versus nonhuman.”

Subsequent experiments bore out that idea: when they ran the test with other nonhuman categories — furniture, flowers, Greek gods — they found the same results as in the animal studies.

This does not mean that participants were doomed to a life of bias, however.

“Implicit bias is like a habit that can be reduced through a combination of awareness of implicit bias, concern about the effects of that bias, and the application of strategies to reduce bias,” wrote the authors of a 2012 study in the Journal of Experimental Social Psychology.

That study found that people who received a racial bias training experienced dramatic drops in bias, with “people who were concerned about discrimination show[ing] the greatest reductions.”

Those findings suggest that while bias is ubiquitous, it isn’t inevitable. “Awareness of these more automatic associations is the first step,” Morehouse said.

“Because once you’re aware, you can break the habit.”