How could it not have an impact on intellectual capacity?
Good nutrition, stimulation, and education are all important during development. This things are all much easier to access when you have more money.
Good nutrition, stimulation, and education are all important during development. This things are all much easier to access when you have more money.
But not so important that they would have a 40 point IQ difference. If it is, show me the studies confirming that.
To start look at http://www.thewayforwardproject.org/file_uploads/Gen10%20IQ%... for a meta analysis of thousands of studies finding that the IQ difference between growing up in an orphanage and foster care averaging 20 points.
Independently, the estimated difference between average IQ in the mid-30s and today is 20 points. See http://en.wikipedia.org/wiki/Flynn_effect for verification. In that time period the main things that have changed are nutrition, stimulation and education.
So there you have it. Two unrelated analyses of completely different things finding that nutrition, stimulation and education can explain 20 point IQ differences between otherwise similar populations.