The Nurture Assumption

The Nurture Assumption: Why Children Turn Out the Way They Do is a book by Judith Rich Harris, with a foreword by Steven Pinker, originally published 1998 by the Free Press, which published a revised edition in 2009. It has been published in at least 20 languages. The book was a 1999 Pulitzer Prize finalist (general non-fiction). Its answer to "Why Children Turn Out the Way They Do" is that "Parents Matter Less Than You Think and Peers Matter More".

The use of "nurture" as a synonym for "environment" is based on the assumption that what influences children's development, apart from their genes, is the way their parents bring them up. I call this the nurture assumption. Only after rearing two children of my own and coauthoring three editions of a college textbook on child development did I begin to question this assumption. Only recently did I come to the conclusion that it is wrong.

Summary

Harris challenges the idea that the personality of adults is determined chiefly by the way they were raised by their parents. She looks at studies which claim to show the influence of the parental environment and claims that most fail to control for genetic influences. For example, if aggressive parents are more likely to have aggressive children, this is not necessarily evidence of parental example. It may also be that aggressiveness has been passed down through the genes. Indeed, many adopted children show little correlation with the personality of their adoptive parents, and significant correlation with the natural parents who had no part in their upbringing.