[pulisse]

Unfortunately, it's also highly heritable, so environmental interventions have a fairly marginal effect on it.

(a) The Flynn Effect demonstrates that IQ is quite responsive to environment.

(b) The heritability of a trait is not a measure of the degree to which that trait is genetically determined: Highly heritable traits can be environmently malleable. (The heritability of height is 0.8, but nutrition, childhood sickness, etc. have a huge effect on height.) Conversely, traits with low heritability can be strongly determined, genetically. ("Number of eyes" is a trait with low heritability, for example.)

(c) The measured heritability of IQ isn't especially high. It's usually found to be in the vicinity of 0.3.

[lazerpants]

Regarding C, isn't that just for children? As I recall it's something like 0.5 or higher for adults.

[johnrichardson]

You're right. Some studies have found it as high as 85%.

https://en.wikipedia.org/wiki/Heritability_of_IQ