r/science • u/mvea Professor | Medicine • 20d ago

Neuroscience 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.

https://www.psypost.org/twin-study-suggests-rationality-and-intelligence-share-the-same-genetic-roots/
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u/Capybara-at-Large 19d ago

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.

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u/isaac_the_robot 19d ago

Are they making irrational decisions, or could they be making rational decisions based on incorrect starting information? A person who is experiencing paranoid delusions could potentially still make rational decisions to protect themself from a threat that doesn't actually exist.

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u/alsuhr 19d ago edited 19d ago

I agree. It's worth rethinking whether rationality is something we can have some "amount" of. As observers we are just as responsible for understanding under what conditions someone might behave as they do, as they are responsible for violating our expectations of "rationality". A piece I really liked that discusses this is "Is human cognition adaptive?" (Anderson 1991, BBS)

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u/Frosti11icus 19d ago

Most decisions are rational from the perspective of the person making them. Calling a decision irrational is more of a privilege of an outside observer. There’s too many variables involved for outsiders to make that call. Making correct Vulcan like decisions requires that your story be written in such a way that you can make correct Vulcan like decisions, but most people don’t get that life.