In 1962, a classical psychology experiment put too many rats in a limited area, overpopulation, where they developed all sorts of antisocial and destructive behaviors. It is called the “behavioral sink experiment”.
http://en.wikipedia.org/wiki/Behavioral_sink
However, there has been no experiment conducted with rats, to determine how rats raised in an antisocial environment behave with rats who were raised in a social environment.
This is essential for another reason. Children who are raised by a heterosexual married couple are raised in a “success” track, oriented to improving their lives; whereas children who are raised by a single parent are raised in a “survival” track, which means they are 60% more likely to criminally offend.
Likewise, “survival track” children will affiliate with each other as a better survival strategy, affiliations that are sub-tribal, like street gangs. That is, such children are so socially devolved that their group aspiration is to become a tribe, even though tribalism is at the very low end of social order.
In situations where social people are in the proximity of the antisocial, while the antisocial group will be able to attack or even kill an individual, with any organization, the social people will quickly crush the antisocial group, unless they make an effort to not do so.
On the grand scale, this is why civilization almost invariably defeats barbarism, unless that civilization has so eroded from within that it is near spontaneous collapse.
On the lesser scale, it describes what happened to Detroit, and what is happening to Chicago and a few other places that are surrendering civility to the law of the jungle.
The Chicago youths have a unique opportunity to shut down all of Chicago. When the rest of the nation recognizes a trip to Chi-Town has real risk, they WILL quit coming. That could not be glossed over or ignored by the MSM.
They did a big one - they called it "busing". :)