Thinking positively: The genetics of high intelligence

I would be very surprised if high intelligence was anything other than the extreme edge of a normal distribution of the human population. For it to be anything other than this it would require people of high intelligence to be a sub-population that did not breed with the rest of humanity.

You could make this argument for any trait. However, some traits are the result of a single gene - e.g., sickle cell anemia and the accompanying malaria resistance. Yet some of these traits occur in large populations that are not strongly inbred.

Only single gene traits. Intelligence (however defined) is multi-genetic - there are thousands of genes that contribute to intelligence. Given this the only way that individuals with high intelligence could be anything other than edge of a normal distribution is if they were part of a human sub-population.

Edit. I should add that the humans are not completely one population because of genetic isolation and differential selection (especially over the last 10,000 years), but we are almost a single population. Like everything in genetics it gets fuzzy at the edges.

"there are thousands of genes that contribute to intelligence"

And the very definition of "intelligence" is incredibly complex and slippery, which is one of the reasons why I've always found trying to summarise such a complex property into a single numerical value such a silly exercise.

Summarizing a complex property into a single numerical value is very useful and not silly. For example, temperature is a numerical summary of huge number of molecular motions.

More on this here: http://slatestarcodex.com/2014/08/11/does-the-glasgow-coma-s...

I didn't say that all attempts to summarise a complex system in a single number are silly - just that intelligence is such a multi-faceted and ill-understood area that, in my opinion, evaluating people based on a single number is silly.

NB I say that as someone who got a very high IQ test result - which didn't exactly convince me that IQ tests are a good idea....

What is the name of the IQ test you took?

Intelligence really isn't "multi-faceted" (read Gardner's own admission that his theory never panned out) and it isn't ill-understood (refer to the Nature or Nurture interview with Nancy Segal on YouTube).

There's two reasons people say that. One is, they fared badly on a test and want to dismiss it, and the other is, they fared well on a test and are bashful about it.

Also, IQ tests are meant to measure a person's intelligence, not to convince them that IQ tests are "a good idea" - for that you would have to study Psychometrics.