Another family of perceptual biases stems from our being social animals (even scientists!), susceptible to the dynamics of in-group versus out-group affiliation. A well known bias of group membership is the over-attribution effect, according to which we tend to explain the behavior of people from other groups in dispositional terms (“that’s just the way they are”), but our own behavior in much more complex ways, including a greater consideration of the circumstances. Group attributions are also asymmetrical with respect to good versus bad behavior. For groups that you like, including your own, positive behaviors reflect inherent traits (“we’re basically good people”) and negative behaviors are either blamed on circumstances (“I was under a lot of pressure”) or discounted (“mistakes were made”). In contrast, for groups that you dislike, negative behaviors reflect inherent traits (“they can’t be trusted”) and positive behaviors reflect exceptions (“he’s different from the rest”). Related to attribution biases is the tendency (perhaps based on having more experience with your own group) to believe that individuals within another group are similar to each other (“they’re all alike”), whereas your own group contains a spectrum of different individuals (including “a few bad apples”). When two groups accept bedrock commitments that are fundamentally opposed, the result is conflict — or war.

Education as Stretching the Mind
Jamshed Bharucha President, The Cooper Union
Source: Edge, World Question Center 2008: What Have You Changed Your Mind About?
http://www.edge.org/q2008/q08_16.html#bharucha