My "Q.E.D." was not making the point that your disagreeing with me constitutes proof of my assertion. It was that every time I have made this assertion to anyone not already familiar with Harris' book, they immediately rejected it, making it a perfect example of the kind of thing the original post was asking for.

As for the mountain of evidence supporting my claim, the "pop psychology books" I linked to are extensively referenced. The easiest way to think about it is to consider twin studies. Since identical twins have the same genes, we can measure the amount of difference parenting makes on personality by measuring the differences in personality between identical twins raised in the same home and identical twins separated at birth and raised in different homes. Numerous studies have shown that there is no greater difference in personality between identical twins raised in the same home and those raised in different homes. Ergo, whatever environmental influences shape personality come from outside the home, not inside.

Studies that purport to show massive influence of parenting style on personality are very frequently flawed, as Harris shows abundantly in The Nurture Assumption. And as far as Vaniver's argument that parental abuse is an exception to all this, I would have to re-read Harris' book, but I'm pretty sure this was covered.

So, approximately 5% of adult personality is dependent on parenting style in current populations in the developed world. That's pretty close to zero.

I think glennonymous is taking that result too far, though: parental abuse is pretty uncommon, and so you can't expect the 5% number also applies to parental abuse- abuse, as it is atypical, should have an effect different from the population mean, whereas non-abuse, as it is typical, should be hard to distinguish from the population mean.

A better way to put it is that the difference between great parenting and mediocre parenting appears small, especially compared to the difference between great genes and mediocre genes and the difference between great peers and mediocre peers.