Bugsy,

I have never maintained anything other than that intelligence arises from a complex interaction between nature and nurture. Yes, I know that nutrition is a major factor in intelligence. In fact it now appears that the nutrition of your GRANDPARENTS may affect your intelligence because of epi-genetic effects.

(Google "ghost in your genes.")

None of this is in dispute.

But there is no well constructed study that shows ZERO effect of genome. The argument is entirely about the extent to which heritability accounts for the variability of intelligence with 40% being the bottom of the range.

There is no selection for dullness or dumbness. But some population groups may have come under increased selective pressure for smartness – for example because of the invention of agriculture or writing. Given the absence of gene flow that would cause a divergence in brain evolution.

In a sense Bugsy we are both speculating about the way the science will turn out. You have one view. I have another. In about a decade or less we'll know who was right.

Actually Steven, you are speculating, I am working on actual data. Nutrition may have epigenetic effects on certain traits (but probably not "intelligence"), but it also has DIRECT measurable and very large effects on your intelligence, right now.

Nutritional status of pregnant women is the major factor for the development of the child, both in the womb and post-natal development. Nutritional status of the child is of paramount importance at every stage of development. This has been well characterised. What hasn't been well characterised are any of the other factors that may have on intelligence, including cultural. To do this you would have to remove nutrition as a variable, which is quite difficult to do with people living under traditional cultures and specific regions.

If you think that genetics is a major factor for population differences, then why do Ashkenazi Jews in Israel score lower on IQ tests than those living in Europe?

Let's see which way it turns out Bugsy

There's no point in arguing now