[Note: askblog had an existence prior to the virus crisis. I still schedule occasional posts like this one.]
At some point, take time to read my review of Kevin Mitchell’s Innate. The book really influenced my thinking about nature and nurture. I think that Mitchell’s ideas are something missing in Charles Murray’s work.
I took away two main lessons from Innate. The bumper-sticker versions of these lessons are:
a) gestation matters; and
b) humanity is a set of individual mental disorders.
Here’s a way to express different theories of Outcomes.
O = G + X + L (units could be standard deviations from average)
For any particular outcome, there are three major contributors, weighted appropriately: Genetics, External Support, and (other) Luck.
The Blank Slate says that the weightings on G and L are very small, and X is very big. If we gave people with low O more X, they will have higher O.
Genetic Determinism says that the weighting on G is large, and those on X and L are very small. It doesn’t much matter what you do, or what happens, at least so long as you above some minimal threshold of X and L, below which things are going to much worse than one’s expected potential, e.g., long-term, severe malnutrition.
The Null Hypothesis only claims that X has a small weighting, and is agnostic about the relative contributions of G and L. However, it tends to reject any claim that insists that any evidence in favor of a low weighting for G implies a high weighting for X. On the contrary, it probably implies a high weighting for L.
Gestational variance is L, and Mitchell’s weighting for L is higher than Murray’s.
I like this formulation
So much of people’s concerns about this divide into “what you’re stuck with at birth” and “what happens in your life”–which can be changed by changing your environment. “Public policy” can change the odds about post-birth luck. For many purposes, I think it would be useful to divide Luck into pre-birth (gestastional) Luck and post-birth Luck.
One of Mitchell’s conclusions seems to be that Genetics plus pre-birth Luck is much bigger than External Support plus post-birth Luck. Which implies that “public policy” in the USA today has much less power to improve things than most people would like.
Nature v Nurture was hard enough. Adding one more catch-all variable is already playing with fire, though in this case, arguably justified, so less likely to get burned. More than that and one is just asking for gaming with statistical garbage.
The Null Hypothesis says that “Everything Else” is much more important than Policy, and if the question is whether or not to allocate more to policy, one can still answer no without having to get into the impossibly messy and contentious details of all the Everything Elses.
You’re right that what this is all about is really “Policy vs. Everything Else,” for individual outcomes. It’s just that genetics is such an important factor, it deserves its own measure. One you take that out, it doesn’t matter what you call what’s left in the “everything else” catchall bucket, and I think it’s reasonable to just call it ‘luck’.
But my memory of the book is that “gestation” or “gestational luck” is also pretty big. How things are divided will have a big effect on how people see things morally. “50% genetics and 50% other” looks a lot different than “80% that nature sticks you with and 20% that can be changed”.
Arnold,
Thank you for this lucid, incisive review essay! One of your best, IMO. I will order Mitchell’s book today.
This is a better formula ,
O= G0+G1+X+L where G1 is gestation.
I agree, because gestation would seem to be potentially controllable.
Not really.
The ‘luck’ part of gestational variance is the kind that helps make identical twins, reared together, come out slightly different.
It’s precisely the part that is hard to control – because the controls were the same – and furthermore, we can be more confident that differences in such similar circumstances have a lot to do with chance. When other kinds of kids come out different, the causal density is too high, and it’s too hard to identify the weights of the factors. The identical twin differences give us a kind of floor estimate on luck.
As I indicated, to the extent there is a role for impact on gestation, it’s likely asymmetric. A pregnant woman hits quickly diminishing returns with fetal outcomes after meeting a fairly low threshold for nutrition and sobriety. But of course it’s still possible to hurt babies and their future outcomes a lot if she’s starving or ingesting toxic quantities of harmful substances.
That’s not a large variance. And how is it a floor estimate rather than just an estimate? If non-identical twins differ more on average than identical twins, that has to be down to different genetics. It is generally accepted that non-linear terms (GX etc.) in O are small.
Excellent and very valuable essay. Clarifies a lot and articulates a sound, well-reasoned, position. “Data-driven anthropology” versus “folk anthropology” is genius and should enter the standard jargon.
I am wondering if brain structure correlates with any “race” or “population” however defined as it does with sex? Or would any such research be beyond the pale?
b) humanity is a set of individual mental disorders.
is similar to Randolf Nesse’s Good Reasons for Bad Feelings: Insights from the Frontier of Evolutionary Psychiatry.
From the Amazon blurb: “Nesse asks why natural selection has left us all with fragile minds. … Nesse shows how negative emotions are useful in certain situations, yet can become overwhelming. Anxiety protects us from harm in the face of danger, but false alarms are inevitable. Low moods prevent us from wasting effort in pursuit of unreachable goals, but they often escalate into pathological depression. Other mental disorders, such as addiction and anorexia, result from the mismatch between modern environment and our ancient human past. And there are good evolutionary reasons for sexual disorders and for why genes for schizophrenia persist.”
which is why educators for the most part try to match students to the demands of a course rather than believing that it is possible to enable low-aptitude students to master challenging material.
Actually, that is largely not true for K-12. Most educators believe, with President W. that that is “the soft bigotry of low expectations”. Instead, just about everyone can successfully complete a rigorous college prep curriculum. In fact, most young people can succeed in college. It is wildly untrue, but it is a beloved bi-partisan myth (1983’s A Nation at Risk was a proud product of the Reagan administration).