Our implicit biases are rooted in biology, but they can be easily manipulated. That's both really good and really bad.
Robert Sapolsky has a bone to pick with oxytocin, or rather the public's perception of oxytocin. It is the love hormone, we've surely all read by now. It helps us bond to our parents, then to our lovers and later to our own children. An extra dose can increase empathy, goodwill, and understanding. But it's not all sunshine and rainbows, here's the catch: those warm fuzzy feelings are only generated for people you already favor. Oxytocin, represented more honestly, is the hormone of love and violence. Its effect in the presence of people you consider "others" is preemptive aggression, and less social cooperation. It creates distance as often as it bonds love, and we are hardwired for those social dichotomies.
Humans invent "Us" and "Them" groups wherever they look, whether it's on the basis of sex, race, nationality, class, age, religion, hair color—there's nothing we won't discriminate against, and we do it within a twentieth of a second of seeing someone. Are they an "Us" or are they a "Them"? The flaw in this hardwired thinking reflex is also its silver lining: it is ridiculously easy to manipulate. A racial bias can be duped by something so simple as putting a cap with your favorite sports team's logo on someone's head, for example. You can overthrow your brain's most primal reactions in this way but, as history shows, other people can also get in your head and manipulate the Us versus Them reflex to tragic and catastrophic results.
Robert Sapolsky is the author of Behave: The Biology of Humans at Our Best and Worst.