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/Sinai 20d ago

It doesn't take much reading between the lines to see that the author thought the very suggestion of general intelligence and rationality being anything but highly correlated was absurd, and did this study because of that.

“1) We found that irrationality, far from being what IQ tests miss, is one of the best IQ tests available. 2) We found that irrationality, far from being unrelated to genetics and more of a mindset, is among the most heritable of psychological traits. 3) Irrationality is making mistakes which are unnecessary: wrong decisions when we have all the information we need, and some simple logic means there is no reason for the error. We found that realizing what information is available, and applying some simple logic, is almost all of the cause of cognitive irrationality. 4) Cognitive ability explained nearly all of cognitive irrationality, and much of the overlap was genetic.”

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u/KristiiNicole 19d ago

So people who have mental illnesses that affect rationality are automatically less intelligent than those without mental illness?

OCD for example, can cause a lot of irrational thoughts and behavior, but I’ve also met some incredibly intelligent people who have it.

Or this another one of those exceptions to the rule kinda thing?

(To be clear, I am genuinely asking with curiosity, I’m not trying to start a disagreement!)

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u/Sinai 19d ago

"Automatically" dismisses the point of using populations in trials, but that being said, people with OCD have measurably lower IQ.

https://pubmed.ncbi.nlm.nih.gov/28864868/

Obsessive compulsive disorder (OCD) is associated with a moderate degree of underperformance on cognitive tests, including deficient processing speed.