Nature! Nurture! Another trite distinction that sounds like it might represent something Fundamental And Real. Seems to have largely supplanted Calvin’s distinction between total depravity vs penance in the people-blaming niche.
See also other quirky binarisms:
- free will/determinism
- sugar, spice, all things nice/slugs, snails, puppy dogs’ tails
- Doctor Who/Daleks
Unlike Doctor who/Daleks, this one is used for actual decision making and public debate outside of Tumblr, so it bears looking in to.
Questions to consider before engaging in discussions of heritability.
First question: When does asking, e.g., “which is more important, nature or nurture?” gain us a useful perspective, or research question? Never. You need to refine it. To recycle a common analogy, imagine a computer science where the central questions were ones like: “can do word processing on my laptop because of hardware or because of software?”. This kind of muddy thinking will have us trying to discern the contribution of “hardware factors” versus “software factors” to “word processing” via a variance decomposition, which is clearly a waste of time. We could surely extract some correlations from that, but it will sbe purely decorative. Anyway, you get the drift. Careful here.
Similarly, if you want to pick an established definition of heritability it would be wise to question what assumptions it entails.
Homework questions: How heritable is English vocabulary size? How heritable is bank balance? How heritable is a bachelors degree in social psychology?
General problem setups
Ozymandias, Shared environment effects are real makes some interesting points about how we discuss shared environment.
Believing in zero role for shared environment also fails to pass the sniff test. Lots of people, I think, will agree that whether or not you talk to your baby might not have any long-term consequences. But the “zero role for shared environment” position requires yourself to commit to the position that all of the following have either zero correlation between siblings or no effect on children’s psychology whatsoever:
- Lead poisoning.
- All other forms of air and water pollution.
- Prenatal nutrition.
- Drinking during pregnancy. […]
Scott Alexander parodies The Gattaca Trilogy
The classic heritability score, are an interesting case study.
Spoiler: Heritability is a linear variance decomposition over two factors, and thus is a very blunt instrument, design for approximate solutions under poverty of data and computation.
Since this research mostly comes from observational studies, one should be suspicious reading research that doesn’t at the bare minimum extend their method to a causal DAG. It’s not my area, but its easy to find a lot papers that don’t.
A lot of, e.g. the twin studies are constrained by lack of data, because of a lack of twins. This might change with advances in genomics.