The average heritability is 49%. This would imply heritability and environmental influences would be about evenly split, no? So, all human traits are influenced by heritability, but they're also influenced by the environment. This finding seems less ground breaking then the title initially suggested to me.
Coincidentally, I'm in the middle of reading "The Neuroscience of You" by Chantel Prat. The author's comments on twin studies:
> some characteristics that have genetic influences, like extraversion, also influence the kinds of environments and experiences people will seek out. And other genetic factors, likes how tall or attractive you are, can influence your experiences by shaping the way others treat you. To further muddy the nature-versus-nurture waters, the rapidly evolving field of epigenetics is showing that environmental experiences can create chemical changes in our DNA!"
> To figure out how surprising the similarities between long-lost twins (or triplets) might be, we've got to ask the question, "How likely is it that any two random strangers who meet on the street would also be similar in this way?"
This was published seven years ago. Its arguments are very sketchy - as if settling nurture versus nature for humans were not social science, as opposed to science.
If identical twins are raised in a wealthy household versus a poor household, how can one determine traits coming from inheritance versus environment? This analysis does not really answer it.
The data of identical twins separated at birth is very light, as one can imagine. A look at the data of the major studies shows there really is not a lot of data - twins are separated at the age of 9 or so, or sometimes are separated at birth and then reunited.
Many of these twin studies are funded by the strange but well-funded Pioneer Fund. You can check out what they were up to in the 1930s if you're interested.
I'm assuming it's fair to say that there weren't many people left in 2022 who believed in a total blank slate? Or was that part still contentious somewhere?
PDF is available here: https://www.researchgate.net/publication/276922271_Meta-anal...
All human traits? How about the trait of being an only child?
(2015)
Where does the "all" come from in this headline. I only read the abstract but I read:
>For a majority (69%) of traits, the observed twin correlations are consistent with a simple and parsimonious model where twin resemblance is solely due to additive genetic variation
69% is not close to all. Especially when (I believe) trait is defined fairly strictly in the study to be something easily measured.