Nature, nurture and friends

If life gives you lemons, what should you make?

Nature! Nurture! Another 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.

I do not have much interest or expertise in this area, but this placeholder will collect a couple of interesting links to refer to next time I get caught up in some aggravating muddy-thinking semantic argument in this area.

See also other quirky taxonomies:

  • mind/body
  • free will/determinism
  • good/evil
  • masculine/feminine
  • salt/pepper
  • Mac/PC
  • Gryffindor/Slytherin/the other ones
  • 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 aside. At risk of weak manning I think we can rule out the usefulness, of the question “which is more important, nature or nurture?” as a useful one. We need to refine it to get to an answerable question. That should go without saying, you would have thought, but pub conversation suggests not. 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. Not that even variance decompositions happen in the pub conversations usually. Anyway, you get the drift. To say anything useful we must make sure we are having a well-posed debate which seems to be challenging in this area for some reason. (Politically charged topic that looks simple enough to have an opinion on.)

Hereafter we are assuming something more nuanced.

Heritability scores

The classic heritability score, is an good case study.

Spoiler: Heritability is a linear variance decomposition over two factors. This is a reasonably blunt instrument with which we can bash results out of meagre data and computation. 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. Or not.

As with any research that 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 is easy to find papers that don’t.

Homework questions for classic heritability scores:

  1. How heritable is English vocabulary size?
  2. How heritable is bank balance?
  3. How heritable is a bachelors degree in evolutionary psychology?


  • 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

  • Jeffrey Lockhart, Blueprint for what in a fairly adversarial review of an evolutionary psychology book, covers some of the weak-manning that happens in this debate.

Evolutionary Psychology

Based on this review, I would like to read Anne Innis Dagg’s “Love of Shopping” is Not a Gene, for some evolutionary psychology amusement.

My favourite Evolutionary Psychology slapfight, because it is dead earnest, is the In Our Time Episode, where Melvyn Bragg is in magnificent form, and the barriers between ad hoc hypotheses are porous.

Bahfest is also neat. It is often quite hard to distinguish satire in this domain from earnestness as per Poe’s Law. For example, is Charlton (2014) actually serious?

Charlton, Benjamin D. 2014. “Menstrual Cycle Phase Alters Women’s Sexual Preferences for Composers of More Complex Music.” Proceedings of the Royal Society B: Biological Sciences 281 (1784): 20140403.