Anti-immigrant policies, race-related demonstrations, Title IX disputes, affirmative action court cases, same-sex marriage litigation.
These issues are continually in the headlines. But even thoughtful articles on these subjects seem always to devolve to pitting warring factions against each other: black versus white, women versus men, gay versus straight.
At the most fundamental level of biology, people recognize the innate advantage of defining differences in species. But even within species, is there something in our neural circuits that leads us to find comfort in those like us and unease with those who may differ?
Brain battle between distrust and reward
As in all animals, human brains balance two primordial systems. One includes a brain region called the amygdala that can generate fear and distrust of things that pose a danger—think predators or or being lost somewhere unknown. The other, a group of connected structures called the mesolimbic system, can give rise to pleasure and feelings of reward in response to things that make it more likely we’ll flourish and survive—think not only food, but also social pleasure, like trust.
But how do these systems interact to influence how we form our concepts of community?
Implicit association tests can uncover the strength of unconscious associations. Scientists have shown that many people harbor an implicit preference for their in-group—those like themselves—even when they show no outward or obvious signs of bias. For example, in studies whites perceive blacks as more violent and more apt to do harm, solely because they are black, and this unconscious bias is evident even toward black boys as young as five years old.