In a series of ingenious experiments at Yale's "Baby Lab," researchers have uncovered instinctual behavior that ranges from the admirable (a basic sense of fairness) to the deplorable (prejudice). You can see the segment here.
What was especially interesting from the perspective of OtherWise, is compelling evidence that being wary of people who are different seems to be hardwired into us. Even babies categorize people into camps of "us" and "them." And they do it based on the most arbitrary characteristics. (For example, whether someone likes the same treats we like.)
Not only are we predisposed to break the world up into groups, we also like people who are different to be punished for their differences.
The good news is that these nasty tendencies can be tempered by society and education. And, in fact, the researchers have demonstrated that many of these biases lessen or even disappear by the time most kids are 8 or 8.
The bad news is that we often regress to our natural self when we're under pressure.