Harris first makes the point that people are predominantly, as in well over 50%, the product of their genes. This is backed up by the solid evidence that seperated identical twins tend to be far more similar than biological siblings or non-biological siblings that are raised together.
Harris does not, however exclude the nuture side of making people turn out the way they are. She says that what parents do is important but that the role of peers in how people turn out is really large and is in a very important way out of the control of parents. Children’s roles in their peer group is something that shapes personality long after childhood.
Harris points out that children rapidly pick up other languages from each other and learn how to behave by observing their peer group.
The argument made in the Nuture Assumption is a strong one and Harris does even look at the counter-examples to her theory of ethnic groups where parents seem to be able to transmit traits one way or another to their children, in particular the performance of Jewish and Asian Americans. She regards this as also being possibly something transmitted by children watching other children.
One of the book’s main points is that parents should not worry too much about how their influence shapes the personality of their child. It’s here that Harris is strongest. She is not suggesting that parents ignore their child but rather that being paranoid about how a child is treated and how this will affect their life is counterproductive and is not backed up by evidence.
The book is an interesting read. What Harris says cannot be easily dismissed. The book is well written and makes its points with calm clarity. It’s well worth a read.