Intelligence: Nature or nurture?

[Jim__]

According to a study in the Journal of Molecular Psychiatry, individual differences in intelligence are (maybe) 40% to 50% genetic:

...

In the first study of its kind, Ian Deary of the University of Edinburgh and colleagues conducted a “genome-wide association’’ analysis to try to gauge the role of genes in intelligence. The researchers analyzed DNA collected from 3,511 unrelated adults to see how much 549,692 common genetic variations known as single-nucleotide polymorphisms were associated with variations in intelligence.

Previous studies involving twins and adopted children have indicated that genes do play an important role in intelligence, perhaps accounting for about half the variation among individuals. But the relative contributions of genetics and environment remain controversial, and it has been unclear how much of a factor genes are. And scientists have been frustrated in their attempts to identify specific genes that may be involved in IQ.

In the new analysis, the researchers calculated that indeed perhaps 40 percent to 50 percent of individual differences in intelligence - both how much someone knows and how good they are at problem-solving - are due to genetic variations. But it appears that the differences in intelligence are due to many genes, each playing a small role. That means it will be difficult, if not impossible, to ever identify any genes that play a major role in IQ, the researchers say.

...

a little bit more ...

The abstract to the paper is here, but you need a login to the journal to read the full paper.

[Johonny]

1. the problem is confusing IQ with innate intelligence I suspect

a mistake made over and over...

[qb]

2. Another variable that would be extremely difficult to control for is the level of intellectual

stimulation the subjects received during crucial periods in their development.