Stefan MolyneuxVerified account

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.

Thank you. Check for understanding: a heritable preference in experience(s) creates a feedback loop that becomes stronger as we have more autonomy?

Also, if this is the correct meaning, can you square that with the second half of what Geoffrey said, re: new genetic influences in adolescence? Just more environment preference?

The new genetic influences can be both, genes coming online, and your genes having more agency over you as you get older and can more pick your environment.

If it is indeed true that "IQ is remarkably stable throughout your life" shouldn't we distrust studies that show some common environmental factor (such as drug use) can significantly lower IQ? Bayesian reasoning gives me powers to see through muddy waters.

Also even if it does reduce iq alot of us have points to spare cant say the same for @StefanMolyneux he cant aford to lose anymore points.

I think IQ is helpful in almost all areas of life, but I wonder if being a popular communicator is an exception.