Wow, that was tough. I figured I'd have a bias toward groups I identify with. And sure enough I came up with a moderate bias to strong preference in one category to groups I identify with. I imagine part of it is from ingrained survival needs. It would be interesting to know if some people don't identify positively with their identified group. If so, that would point to more social influences, I imagine. I guess it's just important to realize that we all have biases, likely toward the people we relied on for survival in infancy and childhood, so it will take a conscious effort to reach out and interact with people who don't look like us.