This blog post discusses evidence that inheritance is, fundamentally, more important than upbringing in determining IQ. The original article is here. The results are striking: when a child is adopted from birth, the adopted parents IQ correlates with the child’s IQ until age 7. But by the teenage years, the correlation is gone – intelligent parents do not have intelligent adopted children, even though they do have intelligent biological children. The conclusion is difficult to avoid.
I have discussed IQ before, and it lead to quite strong disagreement with some knowledgeable people who somehow found my blog. This is (more) evidence – strong evidence – against the position I took in that discussion. The view – my view – that genetics should be ignored by society is weakened by these results. The truth is “obviously” the opposite – genetics do matter, a lot.
I can find some glimmers of hope – some possibilities that nurture may still win, despite the above evidence. But I doubt that the relative importance of nature and nurture will, in this particular case, be overturned. These are discussed at the end.
Like a good scientist, I am therefore going to change my mind and follow the evidence, right? Nope. I’m going to bloody mindedly stand by my opinion that genetics cannot (at least yet) play a role in decision making in society, even though by normal scientific standards it could be counted as a fact.
The scientist with a “non-scientific” view?
How can I possibly justify denying something that I believe to be true?
My reason is that, although we have enough scientific evidence about the effect of genetics on people, we do not have an understanding about the effect of acting on this knowledge. I am petrified by the thought of what decisions might be made on the basis of knowing IQ correlates better with nature than with nurture. Here are just two that could come about if the idea is accepted into the mainstream:
- Intelligent, wealthy, middle classed people will be less likely to adopt from poor and/or unknown genetic stock. As discussed in the links above, it is not rational to adopt children who will not live up to expectations; instead, IVF and other solutions will be preferred. This could result in disaster for those needing adoption.
- People who believe that they have good genetic stock would rationally want to “out breed” those with “inferior” genetics. In today’s class society, that would mean specifically preventing poor (or otherwise undesirable) people from breeding. We’ve seen this before, and it was not pretty.
Do we accept the evidence and put up with the consequences? I say no – although scientifically we can accept these results, they must not be accepted by society.
The responsible scientist
The correct response, I believe, is to place a stronger requirement on the evidence. Essentially, we need to know how to move from the society we have now, to a society that might exploit this knowledge, without causing chaos, misery and unfairness on the way. This requires several things: firstly, an almost unheard of degree of certainty in the scientific evidence that nature trumps nurture, because whilst there is even a glimmer of doubt any policy will be unfair. Secondly, it requires a strong understanding of the social response that people will have to such a policy. And thirdly, we must know how to deal with that in a way that is fair. (a fair rule: we would all agree to it before we know which side of the rule we will fall on.)
The high bar
My previous arguments on this subject focussed on the first of these points, because I’m not convinced that anyone knows anything about the second and third. The burden of proof must be with the nature camp, simply because the implications of it being true could be so dramatic. Therefore I will offer a couple of “get out” clauses to the above research.
Firstly, the results are averages over children that were either adopted or not. If there is a correlation with e.g. parents IQ and being adopted, then these results will be biased by it. (But that still assumes a genetic relationship for IQ, just a different one…)
Secondly, the results cannot account for the effect of “epigenetics“: that is (mostly), the effect of mothers health during pregnancy on the potential of her child. As I discussed previously, this effect is these days being seen as large (hence the “no alcohol” taboo for pregnant women…).
Thirdly, there may be social reasons that adopted children do poorly. If they are told they are adopted, then they may spend their teenage years in rebellion and doubt. If they are not told they are adopted, perhaps the parents still behave differently towards them.
Finally, as I discussed previously, if you assume a (false) social concept is true you may inadvertently make it come come about. People who are believed to have low “genetic IQ” might have low observed IQ – but only because society (and they themselves) expect it to be true.
The most important part of all – disclaimer
In all cases, it is extremely important to remember that these effects are small – they are simply correlations in a whole bunch of causes and effects. They do not predict what will happen for any given adoption, or indeed natural birth. Some children do well in terrible circumstances, and others fritter away privilege. Correlation does not imply causation. IQ does not measure anything other than IQ – and itself only weakly correlates with intelligence. What of happiness, life satisfaction, social responsibility, and so on?