The Logic of Life: The Rational Economics of an Irrational World

The Logic of Life is an economics book in the vein of Freakonomics. It provides logical explanations of seemingly illogical behaviors by people. In many cases, psychological studies tease out logical behavior from seemingly illogical outcomes.
One example was the discussion of racism. "Bigoted racism" would be expected to weed itself out of the business world. If businesses that turn down the best candidates merely because of external characters, would suffer and falter. (A simple example could be seen in basketball where all white teams became at a significant disadvantage compared to integrated teams.) However, "rational racism" is much more difficult to remove because it does provide some "stereotypical" advantage. On average members of certain groups will do better, therefore companies are more likely to hire those in the group. Those in the "out group" still suffer, but companies that practice it are still successful, thus making it more difficult to remove. These groups can also self-reinforce their standing. A Catalan who studies computer science rather than Catalan may be shunned by his community for attempted to do something outside the community. This leads to fewer people being willing to study and succeed and thus an overall reputation of community being inferior. Once the group is deemed inferior, a logical company would prefer the stereotypically better group, and thus perpetuate the inferiority.
Similarly, devolution of areas to isolated ghettos can be explained by a logical behavior. A perfectly integrated community may be functioning well. Each resident likes to have a certain number of similar people nearby, and that balance is properly met. However, if one resident moves out and is replaced by a "different" person, that could upset the balance. Now one person feels they are too different, and move out, this starts the chain reaction which results in the community dominated by a single group.
There are a number of additional examples in other areas of logical explanations for something that seems illogical on the surface. Groups can do strange things when they are composed of individuals doing "logical" things.