2-4 is when it happens, these niggers are raised by their single mothers without any father figure around (and if there is, he's a nigger). This age period is when humans (in a broad sense) learn how to socialize. People who are not socialized by the age of 4 often have significant behavioral issues as their peers will not want to interact with them and they will not develop. This is a direct result of combining low IQ, violently predisposed niggers with government policy that encourages single mothers. It is the result of progressive policies. It can be reduced by getting rid of welfare and mass scale women in the workforce and returning to a more traditional family structure, but due to the inherent violent nature of niggers, it can never be eliminated in that group.