I just have time for a quick post about a G&M article equating aggression with behavioural problems. I don't know if liberal media and research community make this mistake on purpose in order to further the anti-bullying agenda or whether they just don't understand that aggression is a natural behaviour, whereas, behaviour problems are the result of poor social conditioning.
Aggression is a useful trait for sports, business and social circles if channelled and trained properly. If a child is taught proper self-discipline and empathy, aggressiveness will help him or her succeed in the world.
The NYU study, which seems problematic because it is based on parental reports and observation - how much and what type of observation is not stated - really points to socialization by parents. Of course parents who have difficulty socializing with their children will have children with difficulty socializing in school. Acting out, defiance and hostility are the result of poor social skills and self-control. These are learned behaviours.
There are countless ways that an aggressive nature can be expressed. This is shown by the lack of correlation between infant temperament and difficulties in Kindergarten and Grade One. With proper parenting, the children with aggressive temperaments quickly adapted to the school environment and showed no behavioural problems. Poor parenting resulted in problems no matter what the temperament was.
Confirmation bias is astounding amongst Blank Slate believers is astounding. The scientific method cannot filter it out of sociological studies.