From Christopher L. Wood:

Re: Why some kids suffer chronic bullying (Oct. 8): I found this article interesting, but did the researchers consider that the parental evaluations may have been biased? Overly repressive parents may be more inclined to interpret their infant’s actions as “aggressive” and in turn harshly punish them. These infants then experience punishment for simply acting normally, and this learn to react passively, or to expect punishment. More study needs to be done, with objective observers.