Twin study suggests rationality and intelligence share the same genetic roots - the study suggests that being irrational, or making illogical choices, might simply be another way of measuring lower intelligence.

[u/mvea]

https://www.psypost.org/twin-study-suggests-rationality-and-intelligence-share-the-same-genetic-roots/

[u/Capybara-at-Large]

I already know this hypothesis has severe limitations of application because of the amount of highly intelligent people who also have a severe mental illness.

Surely individuals like John Nash and Isaac Newton—who historically made highly irrational choices due to a mental illness that causes delusions and severe lapses in logical reasoning—cannot also be considered low IQ.

There are countless people with schizophrenia, bipolar, and depression who make irrational choices on account of their illness yet are often key contributors to advances in science and culture.

I also believe rationality only highly correlates with intelligence for this reason.

There are too many instances where someone’s ability to be rational is completely gone while their IQ remains intact.

[u/Mylaur → u/Capybara-at-Large]

If they're making irrational decisions due to a mental illness, isn't it because of that mental illness...? Thus the positive correlation between intelligence and rationality doesn't sound valid in that case.