How the brain discriminates

I'm fascinated with human behavior, and in particular how people are constantly looking for differences in the world around them. I don't know if this is an evolutionary response (fight or flight), or is something else. This is a powerful response that allows us to quickly assess what is going on around us, but it does have a down side. I think because it is so powerful, we have the capacity to amplify distinctions that aren't meaningful. This leads to "the battle of the sexes", India and Pakistan, etc. A recent Harvard study looks at neural patterns when people encounter others who are similar and dissimilar to them. "How does the brain differentiate those who are similar to us from those who are different? Does it analyze differences in skin color, language, religion, height, eye color, foot size? Does it discriminate cat versus dog lovers, Pepsi versus Coke drinkers, Shiite versus Sunni, Crips versus Bloods?"

I wonder if we can overcome this through training (education)?