Nature/nurture: James, you might like this

[eckadimmock]

Here's a piece by Times Online on a subject we've previously discussed: heredity and environment as influences on behaviour. Unsurprisingly, they're both important but some interesting research results are mentioned.

[James Hannam]

Thanks for pointing this out and sorry to take so long to look at it.

I thought the article was very interesting but have one major criticism - I am extremely suspiscious of single-gene explanations. This, of course, is where the selfish gene metaphor goes so wrong. Individual genes encode proteins but it is groups of genes that do interesting things like influence behaviour.

So, in the article we hear about gene variants that are apparentally activated by the environment. Trouble is, an important part of the environment are all the person's other genes which may well help determine whether an individual is abused or divorced.

Also, the article has no place for pot luck. It only has room for nature or nurture. As I have often said, I think a large part of it is neither. Science has simply found no cause for about half of our traits so they look like luck, or self determination as those of us who believe in freewill woulda call it.

Still, as you say and interesting article that supports about a 50% genetic compenent.

Best wishes

James

[perplexedseeker]

James,

I've been looking back through your previous posts on the blog on this subject and was very interested by your take on these matters. At the risk of resurrecting an old thread, I thought I might weigh in with what little I know about genetics. As a biochemist, I pretty much take it for granted that some (perhaps much) of that complicated, almost indefinable quality we call "intelligence" is genetically inherited. However, I also feel that to a large extent our concept of intelligence is a cultural construct. I agree with you, I think, that the idea of the "blank slate", if true, doesn't give humans any more freedom than complete genetic determinism would.

But I ask you, as a Christian, does it disturb you that religiosity may be, at least in part, genetically determined as well? I have certainly heard of some studies that suggest as much. What are the implications for salvation if some people are less predisposed to believe in God than others simply due to their inborn genetic makeup?

I must say that during my career as a scientist genetic determinism has been one of the things that has worried me the most. One of my greatest fears is that, as genetic screening becomes more commonplace, people will start designing social policy based on genetic predispositions whilst our knowledge of these things is still far from complete.

Please note I'm not implying anything about you - I have looked back through your blog and seen that your views on this subject are well considered, even though I'm not in agreement with you on all points. I guess what I'm worried about is that as genetic research diffuses through the public domain, a little knowledge can be a dangerous thing, and that people will rush to implement reductive solutions to complex issues.

I have seen compelling evidence of a consensus among neuroscientists that developing brains are in fact much more adaptive and plastic than was previously believed. No two people's brains are wired up the same way, regardless of the way they're initially built by the genes. Even some therapy, like cognitive behavioural treatments, can apparently alter the wiring of brains, potentially with positive results, such as curing obsessive-compulsive disorder and depression (which may have a genetic component). And advances in the field of epigenetics may force us to re-evaluate our view of heredity entirely. I'm not saying that these have a direct bearing on the specific issue of "intelligence". Just that new research may reveal that the environment may play more of a role than traditional genetics will allow (though of course you were right to point out in previous posts that a significant component of the environment is actually due to the genes of your relatives).

Sometimes I feel more optimistic, though. In the best of all possible worlds, perhaps if gifted people of all sorts were to realise that their talents were due in large part to a genetic lottery and not some special achievement on their part, it would result in greater humility and sympathy with those who do not share their gifts. But I often fear the evil that can enter into some people's hearts when they believe themselves to be objectively superior to others. Perhaps it's "in our genes."

Or maybe not. I'd be interested to hear what you think about the social impact of this kind of research in more detail.

Seeker

[James Hannam]

Hello Seeker,

Thanks for your post. Firstly, I'm resigned to having to deal with science as I find it rather than how I'd like it to be. So whether I'm disturbed is not really all that important.

But I remain of the opinion that roughly 50% of quite a lot about us, including intelligence and religiosity, has a genetic origin. The other 50% may be environment, but we haven't managed very well to show it. Once we screen out genetic effects, most correlations disappear.

Now most people can buy a 50% genetic componant. Where they get cross is when you challenge their assumption that the other 50% is environmental when we have very little evidence about how that might work. That the brain is plastic may well be true, but that is what has always been believed - it is the consensus and always has been. The radical work is being done by people who are suggesting environment is much less important than we thought.

And me? I've realised that St Augustine was right about original sin being inherited and unavoidable (though wrong about where it came from). And I can also see that science leaves plenty of room for freewill and self determination. So I'm actually not disturbed at all (beyond general problems linked to the exisitence of evil).

Best wishes

James

[perplexedseeker]

Thanks for taking the time to reply. I suspect this is one of the issues that will run and run, regardless of which way the scientific evidence swings. The eternal problem with applying genetics to humans is of course that it's ethically impossible to run trials that take all the variables into account (not to mention the hundreds of years the selective breeding would take! )

I guess what is really needed are more empirical studies in animals (true, obviously this can't be directly applied to humans, who have much more complex behaviour, but it could still be instructive). One of the things that intrigues me is that outwardly similar phenotypes can be produced by different combinations of alleles, and it seems likely to me that different genes will be modulated by the environment to different extents. There's been some interesting work done recently in mice about permanent alterations in gene expression in the brains of infant mice following rejection by their mothers. I believe it was published in Nature, though I forget which issue. If you have access to a subscription you might want to take a look, since the topic interests you.

I also wonder if anyone's specifically looked to see if living with an extended family makes any difference (as opposed to a nuclear family). The idea being that an extended family or close-knit, relatively closely-related community is a closer approximation to the way humans lived ancestrally.

I do think you're right though that it's better to tackle unpleasant implications of research into human nature head-on and try to work out answers, rather than ignoring them.

Regards,

Seeker