Others claim it goes too far in understating the role of parenting. Judith Harris answers your questions. While my wife has yet to agree, it is for this reason that I think home schooling is the best possible option for the development of intelligent, well-adjusted children. I suppose that's because peer influence tends to be noticed only when it conflicts with what the parents want. There are peer groups that influence their members to do well in school and to avoid drugs and cigarettes.
Children can do remarkable things when they get together.
In The Nurture Assumption I tell the story of a group of deaf children in Nicaragua who came together for the first time in a newly created school for the deaf. These children created their own sign language in order to communicate with each other. Their teachers tried to teach them to read lips but the kids ignored them and developed, over a period of time, a rich new language, capable of transmitting complex ideas. It is unrelated both to spoken Spanish and to American Sign Language. As far as home schooling goes, it seems to work successfully if it involves several kids, not just one, and if the kids have occasional opportunities to spend time with other children of their age.