Which “unhelpful tendencies and problems” occur in both twins with radically different upbringing and which do not?
That doesn’t distinguish between e.g. unhelpful tendencies that occur due to genes that all humans share vs. unhelpful tendencies that occur due to living in an industrialized society.
In general, twin studies only tell you what proportion of the variance in a trait is genetic in a given society. But you can’t use that information to determine whether the trait is evolved vs. cultural; that’s not the question that the studies are asking. E.g. in a society that had a custom of lobotomizing all red-haired people, “being lobotomized” would be an entirely hereditary trait (since hair color is genetically determined) that turned up in twins with radically different upbringing, even though it was an entirely cultural practice. (More examples here, here and here.)
Yeah, I get that shared cultural aspects (including prenatal) are hard to tell from inherited. In this particular case of someone seeking therapy for a specific issue that troubles them, I would expect that the situation can be uncommon enough to stand out in twin studies if the cause is genetic. I am no expert though.
That doesn’t distinguish between e.g. unhelpful tendencies that occur due to genes that all humans share vs. unhelpful tendencies that occur due to living in an industrialized society.
In general, twin studies only tell you what proportion of the variance in a trait is genetic in a given society. But you can’t use that information to determine whether the trait is evolved vs. cultural; that’s not the question that the studies are asking. E.g. in a society that had a custom of lobotomizing all red-haired people, “being lobotomized” would be an entirely hereditary trait (since hair color is genetically determined) that turned up in twins with radically different upbringing, even though it was an entirely cultural practice. (More examples here, here and here.)
Yeah, I get that shared cultural aspects (including prenatal) are hard to tell from inherited. In this particular case of someone seeking therapy for a specific issue that troubles them, I would expect that the situation can be uncommon enough to stand out in twin studies if the cause is genetic. I am no expert though.
It’s not just hard in practice, it’s a question that the studies are theoretically incapable of answering.