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tl; dr
Naomi has a very amusing book on evolutionary psychology.. Amusing because the writer seems to become momentarily preoccupied with some very odd ideas, only to suddenly snap back to reality. The best example thus far was when he was trying to explain the potential root causes of adaptation. He listed design by God, evolution, and (oddly) some kind of seeding from an extra-terrestrial source.

He then goes on to write a couple of paragraphs about how one could test this hypothesis by studying meteorite fragments for signs of life, and talks about the validity of the idea as a scientific theory.. Then he seems to have a sudden realisation that seeding cannot possible account for adaptations, because either the aliens intended for us to have these adaptations (in which case it falls under the heading of design) or the earth was seeded by microbial life which evolved (in which case evolution). At no point does this idea of seeding have anything to do with the origins of adaptation, and yet the author didn't pull it after realising that it made no sense..

Seeding is a special case of one of the other two methods, but it's such an obscure thing to even mention that I don't understand why they bothered..

It's also odd that a theory that often borrows so heavily from the theories of Richard Dawkins could completely miss several fundamental components of what Dawkins was really on about. For example, there is discussion about whether a preference for mating partners that give off cues associated with genetic fitness is driven by genetics, or by the environment in which a person's mind has developed. I don't see the two as being entirely distinct - using the theory of memes, it is entirely possible that the standards a particular culture sets for 'beauty' once varied depending on the community in question, and that over millenia of group selection those cultures whose standards coincided with fitness cues outperformed the others.

So what you then have is group selection based on a meme, rather than a gene, which sets up the standards for what is attractive. This fits entirely within the theory of natural selection, but adds confusion if you're trying to find a root cause. Group selection (and indeed individual selection) would promote a tendancy towards preference for people who look like better mates, both through genetics and cultural transmission. Evolutionary psychology should therefore consider both mechanisms, but thus far I've only really seen the genetic side covered.

My main concern with evolutionary psychology is that there is a very fine line inherent in any individual theories.. If a theory is specific to individual behaviours, then one must call into question the relevance of those behaviours in the environment of evolutionary adaptedness - the set of conditions under which such behaviours evolved. This period tends to be very old, so behaviours that seem specifically suited to solving problems in today's modern world are either learned behaviours, or are side-effects of other behaviours that were once useful.

For example, homosexuality could be explained as a side effect of a gene that, during the EEA for humans, directed fathers to take a more maternal role in parenting. This adaptation would have arisen in response to better tool-making - as the cost of hunting decreased, group selection would suggest that reassigning some hunters (males) to parenting might be beneficial to the fitness of such a group. There would need to be a genetic balancing act that limited the number of these more maternal males, so that the entire tribe didn't just put down their weapons and stop hunting completely. Let's say that the optimal situation would be that 10% of males took a more maternal role, while the other 90% remained in their existing hunting role. Fast forward to the present day, and the phenotype of the gene is expressed by an alternative sexuality.

Explaining homosexuality directly using evolutionary psychology requires us to find a time in the distant past of our species when such a gene would have arisen, which in turn requires evidence, which is not exactly abundant. I can theorise all I want, but it gets me nowhere, and therefore evolutionary psychology is of no use in explaining that trait.

On the other side of that fine line are the sweeping generalisations.. Evolutionary psychology being used to explain larger structures within the brain, and broad components of the psyche. Things like memory, sense of direction, etc.. In these cases, it becomes much more like evolutionary biology - you're looking at the physical evolution of the brain. While interesting, it's hardly a distinct area of science - it's just a narrow part of biology.

I suppose for me, an important part of psychology is answering "why" to various questions about behaviour. Those questions tend to rise because of individual differences - why does A act like this, and B act like that. The problem with evolution as an explanation is that, typically, in a stable population under little selective pressure, variations are unlikely to arise for any particular reason, and any variations that already exist are likely to be selection-neutral. It's like blue and brown eyes - I can explain why some people have blue, and some people have brown, but ultimately it makes no difference to the people involved. Similarly, in evolutionary psychology, the only current differences that can be explained are likely to come down to random differences in inconsequential traits, and that's not all too interesting.. In a low-pressure environment, it's a lot harder to work out why something should be as it is, because generally there's no selective force acting on the population that could explain it.

And don't get me started on the heritability of psychological traits. I'll agree that the mechanism by which I store memories and respond to jokes is likely to be the same as my parents, and that these traits are genetically powered. But again, they're more like biology than psychology.. And everybody does these things the same way, so where's the interest? Find me somebody who doesn't laugh, and explain why their genetic situation might have arisen based on selective pressure, and that would be interesting..

Which is not to say that I don't enjoy reading about it, because I do.. I just have to take everything with a pinch of salt, because usually things are either so biologically-driven that it's uninteresting to me, or it's so psychological that it's a product of today's environment, not the EEA, in which case it's not driven by evolution anyway. Right now, I'm preferring economics - markets are driven by evolution on a much faster timescale - adaptation happens much faster, and is sometimes (but not always) by clear design, which gives you a much richer environment to look at. It's almost enough to tempt me back into education.. :o)


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