In some ways, it’s super simple. People learn to be whatever their society and culture teaches them. We often assume that it takes parents actively teaching their kids, for them to be racist. The truth is that unless parents actively teach kids not to be racists, they will be,” said Jennifer Richeson, a Yale University social psychologist. “This is not the product of some deep-seated, evil heart that is cultivated. It comes from the environment, the air all around us.”Richeson compares children's instinctive formation of biases to a student at a new school. “When you arrive at a new high school. You are instinctively trying to figure out who’s cool, who’s not, who’s a nerd, who gets beat up? Kids quickly acquire these associations,” she said. To get a sense of just how pervasive and imperceptibly our environment can affect us, one study at Tufts University found that even with a TV show on mute displaying scenes with no explicit discrimination, the nonverbal body language of black and white actors interacting was enough to cause watchers to test higher for implicit bias afterward. “An us-them mentality is unfortunately a really basic part of our biology,” said Eric Knowles, a psychology professor at New York University who studies prejudice and politics. “There’s a lot of evidence that people have an ingrained even evolved tendency toward people who are in our so-called 'in group. But how we define those groups, and the tendency to draw divisions along racial lines, is social, not biological, he added. “We can draw those lines in a number of ways that society tells us,” he said.