Stefan MolyneuxVerified account

Nope. Longitudinal studies can't reveal causation unless they do random assignment or include twin/family design that can control for genetic confounds.

The study followed individuals for over 20 years, testing their IQ at 13, and then in their 30s

Kids with genes that cause them to have slower growth in intelligence between 13 and 30 might be more predisposed to take drugs. Causation has not been proved.

IQ is remarkably stable throughout your life, even from childhood – please try and get up to speed before muddying the waters any further

IQ is quite stable, but heritability increases until early 20s, and developmental behavior genetics shows new genetic influences affect IQ in adolescence & young adulthood.

When people say heritability increases, it confuses me. Does that mean the expression of IQ changes and trends towards the heritable mean of the parents, despite being higher or lower earlier? It sounds like you get new genetic material or new genes come online, otherwise.

I think it's because genes come online, and people have more control over their environment as they get older so the environment you were born into has less impact and the environment your genes "want" has more.

It didn't seem to hurt mine, I'm still in the =/> 99.9% but I've always been anomalous and enigmatic. TBH part of the reason I started smoking was it made stupid people more tolerable, or me more likely to not notice their idiocies.

Aren’t all studies?

Every study is going to do their best to specifically control to find causation, that doesn’t mean that’s what they are going to get. The only way to get objective correlation is to force someone or a whole group containing some who would never have done in the first place.