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Culture Nature

‘The Mating Mind’ by Geoffrey Miller

I’ve just read The Mating Mind: How Sexual Choice Shaped Human Nature by Geoffrey Miller. The book’s argument is that many of the typical characteristics of human behaviour are best understood as products of sexual selection. Sexual selection is the process where you start with some ancestral bird species where the females have a bit of a thing for longer tails, and a few thousand generations later, they’ve evolved into peacocks. I suppose there are two key insights I’d take from the book, neither of them completely new to me but worth being reminded of.

The first is this – it’s easy to think of natural selection as being driven by adaptations for survival, with sexual selection being almost cosmetic in its effects. It doesn’t matter how good-looking you are if you starve, die of disease or get eaten by a lion before you get a chance to breed. But from an evolutionary perspective, there’s no point in living to a ripe old age if you can’t attract any sexual partners. Both scenarios are evolutionary dead-ends. Also, selection is not necessarily an either-or process (either you survive or you don’t; either you breed or you don’t). Rather, it’s driven by differential rates of reproductive success. And within a well-established species, it’s easy to see how the biggest single factor in determining reproductive succcess will often be the ability to attract a mate. The results of sexual selection will often appear cosmetic – coloured feathers, or an attractive song – but that’s just because those are the things a potential mate is able to perceive. It doesn’t mean that sexual selection is a less powerful force than ‘normal’ natural selection. In a sense, this is an obvious insight; anyone who has ever heard a nightingale or a blackbird singing must be aware of how much effort it is costing them, and there are few more spectacular adaptations than the plumage of a bird of paradise. And just because sexual selection mainly operates on external features, it doesn’t mean that it is limited to those features. Applied to humans, it doesn’t have to be limited to skin colour, breast size and hip-waist ratios. There’s no reason why it can’t also operate on people’s ability to hold a conversation, or dance, or sing. The only requirement is that there must be some genetic component.

The other insight is that anywhere in nature where we see an oganism with a physical feature or behaviour that doesn’t seem to have any survival benefit, it’s worth considering sexual selection as the explanation. Natural selection is inherently thrifty – we should never expect to see energy being expended without there being some reason for it. If that reason isn’t survival, pretty much the only other possibility is an attempt to attract mates, either directly or via increased status. And sexual selection can take almost any form. There are reasons why some adaptations are more likely than others, but the process is essentially arbitrary; once some trait becomes associated with sexual attractiveness, it’s a self-sustaining trend. The explanation is almost too powerful – you can see how it would become a lazy assumption faced with anything slightly unexpected, but as far as I can see, it’s very difficult to disprove. Geoffrey Miller certainly sees sexual selection everywhere – he uses it to explain sport, art, poetry, music, language, dancing and indeed just about everything that makes us human.

I find this argument moderately persuasive, I must admit. As ever, there are questions about which human behaviours can really be seen as written into our genes; can music making really be seen as an evolved trait? Or sport? They seem to be human universals, so it’s not a ridiculous idea, but I’m still slightly wary about making the assumption. But for more obviously evolved traits, like language, it seems very plausible that sexual selection would be the principle driving force.

On the whole, though, I found the parts of the book about human behaviour less interesting than those about sexual selection generally. I’ve read about sexual selection before but to have it treated in depth as a subject in its own right was helpful. For example, the classic examples used to illustrate sexual selection involve dramatic sexual dimorphism, as with the drably-plumaged peahen, or the difference in size between male and female elephant seals. But Miller points out that those are a special case where a few successful males account for the vast majority of offspring. Even in species which form largely faithful pairs, there is an advantage in being able to attract the best (healthiest, most fertile) mates. In that situation, the effects of sexual selection will be less dramatic, but will still be present. For example, in bird species where colourful plumage is found in both sexes, they have traditionally been referred to as ‘species markers’; Miller suggests that these could still be the results of sexual selection.

So I would have liked more of the book spent on sexual selection in general, with more illustrative examples from other species, and slightly less of the human stuff at the end. But it’s a good book, and I recommend it.

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Nature Other

Bad science reporting

Ben Goldacre says (full article here):

There is one university PR department in London that I know fairly well – it’s a small middle-class world after all – and I know that until recently, they had never employed a single science graduate. This is not uncommon. Science is done by scientists, who write it up. Then a press release is written by a non-scientist, who runs it by their non-scientist boss, who then sends it to journalists without a science education who try to convey difficult new ideas to an audience of either lay people, or more likely – since they’ll be the ones interested in reading the stuff – people who know their way around a t-test a lot better than any of these intermediaries. Finally, it’s edited by a whole team of people who don’t understand it. You can be sure that at least one person in any given “science communication” chain is just juggling words about on a page, without having the first clue what they mean, pretending they’ve got a proper job, their pens all lined up neatly on the desk.

Amen, brother.

Of course, it’s not just science reporting. Any time you read an article in the paper on a subject where you have some specialist knowledge – Anglo-Saxon poetry, or birdwatching, or husky racing – it’s always riddled with inaccuracies and misleading phrasing. But inaccurate reporting on Anglo-Saxon poetry is pretty harmless, whereas inaccurate reporting of, say, research into the MMR jab can scare a lot of people, undermine confidence in medicine and potentially cost people their lives.

I vaguely assume that in the core news subjects (politics, business and sport, especially) the reporters have enough real expertise to know what the important stories are and how to present them accurately, even if they don’t choose to do so. But perhaps they’re floundering around in the same fog of ignorance that seems to afflict science journalists.

Categories
Culture Nature

‘The Ancestor’s Tale’ by Richard Dawkins

I’ve just read The Ancestor’s Tale by Richard Dawkins. The book traces back human descent to the earliest forms of life as a ‘pilgimage’, marking the points where other branches of our family tree ‘join’ us; the first rendezvous is with the chimps, then the other apes, then the rest of the primates and so on back to the simplest forms of life. At each rendezvous, Dawkins picks out one or two species from those who have joined, and tells their Tale, which is used to illustrate some point about natural selection – the Peacock’s Tale is used as an occasion to talk about sexual selection, for example. Some of these points are theoretical, others deal with practical issues like the difficulties of dating some of the points on the tree, or interpreting fossil evidence.

The approach allows him to touch on all sorts of different aspects of biology and build up an overview of evolutionary science, while also maintaining a kind of narrative structure. If you’ve read some of his other books, many of the preoccupations and some of the examples are familiar, but there are always enough surprising bits of information to keep you interested (in many plants, the thread-like roots are actually created by a symbiotic fungus). The family tree is interesting in itself; I was surprised to learn that we are more closely related to sea urchins than to snails and bees, for example. Or if that relationship is a bit distant: We are more closely to trout than trout are to sharks. That is, we share a common ancestor with trout which is more recent than the common ancestor of the trout and the shark. We and the trout both have bony skeletons; the shark is cartilaginous.

It’s a big fat book, and occasionally it drags a bit, but on the whole I found it absorbing and Dawkins’s prose is (nearly) clear as ever. So I’d recommend it.

Categories
Nature Other

Intelligent Design

God Chimes in on Intelligent Design. Creationism seems like such a soft target. It scares me silly that anyone takes it seriously.

Categories
Nature

this made me giggle

From the New Scientist RSS feed:

‘Tenth planet’ may be bigger then expected
A space telescope used to place an upper limit on the object’s size was in fact pointing in the wrong direction

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Nature

the difference between reptiles and amphibians

[EDIT: People keep finding this site by Googling ‘the difference between reptiles and amphibians’ This is the basic answer:

Amphibians are frogs, toads, newts, salamanders and caecilians.

Reptiles are snakes, tortoises, turtles, lizards, crocodiles, alligators and a few other oddities. Dinosaurs were reptiles.

Reptiles are more fully adapted to life on land than amphibians. The biggest difference is that amphibians typically need to return to the water to breed, because their eggs need to be kept wet. Reptile eggs have a tough outer shell that prevents them from drying up.

Amphibians [with a few minor exceptions] have a larval stage (i.e. tadpoles/polliwogs) when they breathe underwater through gills; when they become adult, they develop lungs and need to come to the air to breathe. Reptiles have lungs from the moment they leave the egg.

As a further adaptation to life on land, reptiles have scales. Amphibians have smooth skins, and many species need a fairly damp environment so they don’t lose too much water through their skin, although some are adapted to much dryer conditions.

Mammals and birds are evolved from reptiles. Reptiles are evolved from amphibians. correction: amphibians and reptiles evolved separately from an early tetrapod ancestor. Amphibians are evolved from fish.

I hope that helps, Google-people. END OF EDIT]

The first in an occasional series of things which are ‘Something Every Educated Person Should Know’.

When I was at university, as someone interested in science but doing a degree in English, I was frequently annoyed by the wilful ignorance of both academics and students on scientific topics. And I mean wilful – they took a coy, self-deprecating pride in not knowing about ‘those kind of things’. I just think there’s no excuse for taking pride in your ignorance about anything, whether it’s the Britney Spears back-catalogue, Slovakian dialling codes or the second law of thermodynamics.

Anyway, that’s when I started fantasising about writing a book called What Every Educated Person Should Know, which would just lay down the minimum that anyone ought to know who thinks of themselves as educated. Most of the things I thought of then were scientific; I can’t believe it doesn’t bother people that their understanding of how the universe works is often three hundred years out of date. But it would also cover literature, art, geography, politics and general knowledge of all kinds (I don’t claim to know everything, btw – a musician’s list of SEEPSKs would certainly catch me out – this is just a venue for my irritability).

So, SEEPSK #1. One of the presenters on Today this morning had to correct himself after a flood of emails about his reference to a salamander as a reptile. I think it was Edward Stourton, educated at Ampleforth and Trinity College Cambridge, and the man doesn’t know a reptile from an amphibian. Aargh!