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Category Archives: Evolutionary Psychology

What do you mean: ‘hardwired’?

In a previous post I talked about some research which was (mistakenly, I think, and so do the original researchers) presented as revealing ‘hardwired racism’ in the brain. Whatever that research means about racism, or, however weirdly, what racists think it means, that started me thinking about what ‘hardwired’ might really mean. Here’s an online definition:

hard-wire (härdwr); tr.v. hard-wired, hard-wir•ing, hard-wires
1. To connect (electronic components, for example) by electrical wires or cables.
2. To implement (a capability) through logic circuitry that is permanently connected within a computer and therefore not subject to change by programming.
3. To determine or put into effect by physiological or neurological mechanisms; make automatic or innate: “It may be that certain orders of anxiety are hard-wired in us” (Armand Schwerner).
http://www.thefreedictionary.com/hard-wired

The first meaning is almost literal, though ‘hard’ metaphorically implies more permanence than just ‘wiring’ as a verb by itself; the second meaning is metaphorical, in that there are unlikely to be any actual wires involved, but still factually follows on from the first. Even here, some of the ‘wiring’ could actually be logic programming, but programming which isn’t accessible to change. So it’s ‘harder’ programming than the ‘firmware’ in your camera, which can be changed, but is left unchanged in normal use, and the software I’m using to write this (though strictly speaking Windows and Word are firmware, from the description I’ve just given).

The third meaning here is completely metaphorical, and it’s always necessary with metaphors to be very careful to work out where the metaphorical meaning stops. Metaphors are innately dodgy and misleading, as Terry Pratchett has Carrot Ironfoundersson point out: “…Going Up in the World is a metaphor, which I have been learning about, it is like Lying but more decorative” (Pratchett, 1989, p183).

Also there are two different meanings under 3): a) to put into effect by physiological mechanisms, and b) to make automatic or innate. I don’t see that b) follows from a) and I’ll argue that through below.

I think there are two kinds of hardwiring that neuroscientists and psychologists talk about. One kind derives from the basic physiology of certain sensory and mental processes, and is likely to be shared with other animals, because that’s just the way these things have evolved to work. Basic visual processes in humans are like this, as is the link between brain activity, the hypothalamus, the adrenal glands, the release of adrenaline/epinephrine into the blood, and at least some of the effects of that release. It is easy to see how some of these basic mechanisms could be evolutionarily modified from a basic plan from species to species. Since Pavlov’s day, we’ve been learning more and more about the physiology and neuroscience of eating and satiety, and probably all mammals share some of the same basic processes, but it would make sense if it were balanced differently for continuous eaters like pandas and shrews, the complex feeding patterns of grass-eaters, or opportunistic omnivores like humans, and we have a hard-wired explanation of obesity built round this*. That roughly corresponds to 3a), and does certainly contain some automatic and innate mechanisms.

The other idea about hardwiring is sociobiological and is evolutionarily vaguer. Certain patterns of behaviour are more likely to lead to the production of reproductively successful offspring, and so are naturally selected. This only works in Darwinian terms if that pattern of behaviour is innate and automatic, such that it can be genetically transmitted and maintained. Other patterns of behaviour which are equally advantageous could be passed on culturally, and might well be selected and maintained, but here we’re talking about memes and behaviour that isn’t innate and automatic, that it can still evolve by a process of cultural selection. So how can you tell which is which? In some cases, like the excellence of traditional music, the evolutionary success of the book, and the story of the rat bone in the restaurant meal, it’s pretty clear that this is memeic (is that the right word?) evolution, but in others, like altruism, reciprocity, and male promiscuity** it seems to me that it could logically go either way. Sometimes the argument seems to me to be circular: how do we know it’s naturally selected? Because it’s a common feature of human behaviour? Why is it a common feature of human behaviour? Because it’s been naturally selected! I think this logic applies almost as well to using books instead of clay tablets as it does to behaviour in prisoner’s dilemma games.

More convincing supporting evidence might come from studies that show similar social/psychological processes in non-human mammals to those in humans, especially those which can be neatly fitted into evolutionary advantage arguments. Patterns of behaviour which can be described as reciprocity, cheating, and grudge-bearing, as discussed by Dawkins (1981) would be an example. What doesn’t count as supporting evidence is fantasies of the lifestyle of pre-human or early human hunter gatherers, where ‘hardwired’ gender differences are held to derive from the habits of cavemen going out hunting mammoths (and having a bit on the side, as shown by the well-known principle that ‘what happens on the hunt stays on the hunt’), while the cavewomen (cavegirls?) stayed home, gathering berries and digging roots – and caveyouths demonstrated their breeding fitness by rites of passage which involved wrestling with dinosaurs, probably.

There is a useful discussion by Thomas Martin of the background to the hardwired metaphor and what it might mean for human nature from an anarchist point of view here: http://www.socialanarchism.org/mod/magazine/display/128/index.php. It’s worth reading the first part for a summary of where the idea in sociobiology/psychology comes from and then, as he points out in the intro (below), the implications that might have for our understanding of the nature of human nature:

In these first years of the new century anarchism, as a philosophy and as an ongoing praxis, is faced with a number of disconcerting adjustments. Chief among these is the growing evidence that we, along with most other ideologies on the Left, have based our theory on a mistaken concept of human nature. We have learned over the years to distrust words like sociobiology, evolutionary psychology, cognitive science, and above all that dreaded buzzword, “hard-wired” — yet we can no longer ignore the fact that these sciences are probably right about human nature. It does exist; it has biological roots; and while it does enjoy a large measure of free will, its most basic drives and emotions are indeed hard-wired. The Left has long resisted and denied these facts, on the grounds that they might justify discrimination based on heredity, or that they militate against the possibility of radical social reform, or both. I hope to demonstrate that these fears are groundless.
Martin (2006: intro)

There are some bits of Martin’s account I disagree with strongly, especially the idea that genes might ‘want’ to do anything, which he raises later, and you might not want to get into the anarchist thinking at the end, but it does discuss some of the problems that this idea gives to psychologists – and recognises that we may have to accept some inbuilt, evolutionarily selected, forms of behaviour.

But even if you accept that some aspects of our psychology are, metaphorically, hardwired, that doesn’t mean that they’re rigidly fixed. One of the most clearly hardwired bits of our behaviour is the ability to see yellow. In our retinas, we don’t have receptors for all the different colours of light. All we have are cells which are most responsive to red light, to green light, and blue light. So we can’t detect yellow light as such. Pure yellow light that falls on the retina stimulates both the red sensitive cells and the green sensitive cells to roughly the same degree, and when we get this ‘equal red, equal green’ signal, we see it as yellow. But we get the same signal if equal amounts of red and green light fall on the retina at the same time, which is why the television screen, which only shows red, green or blue light, can show us what appears to be a bright clear yellow. Now, we know about the ‘wiring’ of this. We can identify the colour sensitive cells, and we can even track the signals through to where they are combined in the brain to generate a ‘yellow’ channel. This goes beyond vague metaphorical hardwiring: if nerves be wires, then we know what the wires are. We can also trace the evolutionary background to this ability by comparing our visual system and retina with that of other mammals. But, although hardwired, this isn’t a fixed, rigid system. Old-fashioned incandescent room lighting is much yellower than sunlight, but when we are in an incandescently lit room we don’t see the yellow bias, and we see the range of colours that we might see in sunlight. Our responses to the signals from our retina are substantially shifted to compensate for the changed colour of light – without realising it. You can see how big the shift is by taking a photo with a camera in incandescent light (with ‘auto white balance’ turned off). It looks distinctly yellowish, where to us the scene looks as though it was illuminated by white light. As we get older, the fluid in our eye becomes tinged with yellow – so the whole world becomes yellower as you get older – but we’re not aware of this. The only place it shows up is where older people find difficulty in making out white letters on a yellow background, or vice versa.

OK, that’s unconscious, cognitive overriding of hardwiring – maybe by other systems which we might regard as being hardwired too. But here’s another example of how hardwiring can be modified and overridden by cultural and individual variation.  Our bodies have evolved to cope with ethanol, a naturally occurring poison which has a range of damaging effects. Our livers can remove it from the bloodstream and we have an enzyme alcohol dehydrogenase, to support the breakdown of alcohol to less dangerous substances. I guess if you’re being picky, you could say that this is hard-moleculed rather than hardwired. But since we enjoy some of the toxic effects of alcohol, we found ways of supplying alcohol in sufficient quantity to temporarily overwhelm this system, and cultural patterns to encourage, reward and control this overdosing. And metabolism fights back, as it’s well designed to do, by increasing the amount of alcohol dehydrogenase in the system, but the determined drunk just ramps up the input. We quite quickly develop the technology to move from 5% alcohol to 15% to 80%, and also provided a cultural overlay which makes Bollinger and Laphroaig more expensive and more desirable than straight 13% and 40%. OK, there are genetic (hardwired) differences in people’s ability to metabolise alcohol, but it’s clear that cultural factors are important in the role alcohol plays in our lives.

*I’m not sure that this is quite the same as saying that individual differences in obesity are ‘genetically determined’. My first interpretation of the genetically determined explanation was that it must derive from rapid evolutionary change, so that, sometime, in the twentieth century, there was an environmental/cultural change such that fat people got much more sex than thin people, so fatness was rapidly selected for, rather like the way the colour of the peppered moth changed with pollution levels over the last two hundred years. In retrospect, I think I’d oversimplified things, but I’m still in favour of lots of sex for fat people.

**The gender difference here might be overplayed. Traditional wisdom sometimes has it otherwise: see Willie McTell’s Married Man’s a Fool (If He thinks His Wife loves No-one Else But Him) http://www.youtube.com/watch?v=KiODT4nKbcc, evolving into the Ry Cooder version: http://www.youtube.com/watch?v=NXjmkTuYPZU. On the other hand, it’s traditionally well-known that All Men Are Bastards, but that probably covers more than just infidelity.

References
Martin, Thomas (2006) Anarchism and the Question of Human Nature Social Anarchism Issue 37
at http://www.socialanarchism.org/mod/magazine/display/128/index.php

Pratchett, Terry (1989) Guards! Guards! London: Corgi

Warning: if you read this post, your hard disk will be wiped and all the sweet fluffy kittens within a two mile radius will die horribly!!!!!!

This warning was issued by Microsoft* this morning… you know the rest.

BUT we should take these warnings seriously – because they are themselves viruses which are evolving and spreading through our systems and our minds.
Another post about some kind of evolution; I’ll stop after this one.

This post is a summary of a paper presented {sometime} at {some conference or other} that I went to. I think the 1998 IRISS conference in Bristol, but I’m not sure. I don’t know who presented it either. If anyone knows, please tell me, so I can credit them properly, because it was a great presentation.

Generally, people know that paedophiles aren’t harvesting baby pictures from Facebook, or watching YouTube videos doesn’t allow Russian gangsters access to your building society account – but the dreadful warnings keep coming. Why do these memes do so well?

Generally humans, because of sophisticated but fallible information transmission systems (talking and singing), are good vehicles for meme evolution. That’s how traditional music works, after all (see last post). The world of blogs and Twitter is a competitive memeocracy, after all, but there’s some information or aesthetic gain there. What makes the useless, stupid virus warnings viable? They are alive and well out there: I glimpse one passing through my patch of the Facebook jungle about once a month.

The case presented at the conference was: they’ve got access to mechanisms for rapid multiplication and transmission, so they can quickly reproduce themselves millions of times to allow for very high fatality rates (like oceanic fish); they have very low energy needs (copy and paste or a click on ‘share’ is all they need to survive) and (and this is the bit I liked) they have a mutation mechanism to provide the variation they need for evolution. Although the lowest-energy form of reproduction is to pass them on directly, people find it difficult to do that without changing something: removing new lines, changing the spelling, adding or removing exclamation marks…..

Compare these versions of the ‘Budweiser Frogs’ virus warning:

URGENT READ IMMEDIATELY. NOT A JOKE!! READ IMMEDIATELY AND PASS ON TO EVERYONE YOU KNOW! Someone is sending out a very cute screensaver of the Budweiser Frogs. If you download it, you will lose everything! Your hard drive will crash and someone from the Internet will get your screen name and password! DO NOT DOWNLOAD IT UNDER ANY CIRCUMSTANCES! It just went into circulation yesterday. Please distribute this message. This is a new, very malicious virus and not many people know about it. This information was announced yesterday morning from Microsoft. Please share it with everyone that might access the Internet. Once again, Pass This on Please!!!!!!

Subject: READ IMMEDIATLY AND PLEASE CIRCULATE
NO JOKE…
READ AND PASS ON TO EVERYONE YOU KNOW Someone is sending out a very cute screensaver of the Budweiser Frogs.
If you download it, you will lose everything! Your hard drive will crash and someone from the Internet will get your screen name and password! DO NOT DOWNLOAD IT UNDER ANY CIRCUMSTANCES!
It just went into circulation yesterday. Please distribute this message.This is a new, very malicious virus and not many people know about it. This information was announced yesterday morning from Microsoft. Please share it with everyone that might access the Internet.
Press the forward button on your email program and send this notice to EVERYONE you know.
Let’s keep our email safe for everyone

Both these examples from http://www.hoax-slayer.com/budweiser-frogs.html: thanks.

No, you may never have heard of the Budweiser frogs: it was a long time ago. But that’s the thing about these parasites; they can evolve and change their hosts. The same warning will appear linked to the Jimmy Carr sex tape, when it emerges.

It’s difficult to resist the tamper urge. I deliberately didn’t insert the missing space in the second example, but I did reformat it a bit to fit the layout of this blog. Of course. That’s what you do.

I guess/hope someone is studying these things systematically, but I couldn’t find anything in a quick search. Please let me know if you know of any research.

It’s not just the reproductive mechanism, of course: there’s information content as well, which is probably where they adapt, through random editing and evolve into currently viable forms.  These messages show who we’re afraid of: paedophiles, communists, Russian gangsters, your future employer, council snoopers – or just ’someone from the Internet’. In content, these warnings are related to urban folktales. One explanation for urban folktales is that they express our hidden fears. In this case, distrust of technology, and the uneasy feeling that people out there can reach out and fiddle with your computer without you knowing (Microsoft messes with my computer while I’m asleep: I got a warning from them this morning).

Urban folktales are very adaptable: stories like The Twopenny Lean, The Phantom Hitchhiker, The Holland Handkerchief, The Fatal Hairdo, The Rich Beggar go on from generation to generation and get changed according to social conditions and fashions. I first heard The Fatal Hairdo about a beehive hairdo (about 1960-65), but it only took that form for a few years before it moved on. If you don’t know about these, http://www.snopes.com/ is a good source, or a series of books by Jan Harold Brunvand. His homepage is at http://www.janbrunvand.com/

There must be must be some online versions by now: an email which mysteriously arrives with a request to pass it on to the sender’s mother, which turns out to have been sent (from an IP address that doesn’t exist) by someone who died just a year before, or a Facebook account which was mysteriously wiped at the exact moment the tsunami hit (yes, I know neither of these really make technical sense, but that’s not important: neither does The Fatal Hairdo). If anyone knows any of these, I’d love to hear them. I’ve heard the one about the real origin of the term ‘bug’. Snopes.com has a few examples of scams and warnings, but no real social media ones.

Of course, there’s always the one about video games rewiring our kid’s brains.

*Why never Apple? Is it because the folks at Apple are too cool to care about those kittens?

How does music evolve?

Two questions about music and evolution. How did humans evolve to be musical? (last post) How does music evolve? (below)

 Warning: this starts with interesting stuff about the psychology of music and evolutionary mechanisms applied to non-biological systems, but then drifts off into quite a lot about traditional music.

An experimental demonstration of how random sounds can evolve into something that seems quite musical by means of human selection. Here’s an intro to the project on Psypost: http://www.psypost.org/2012/06/on-the-origin-of-music-by-means-of-natural-selection-12336

It’s more fully written up in the paper: Evolution of music by public choice by MacCallum, Mauch, Burta, and Leroia of Imperial College London and the National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan at http://www.pnas.org/content/early/2012/06/12/1203182109.full.pdf

Published in the Proceedings of the National Academy of Sciences of the United States of America (PNAS) in 2012. Here’s their abstract:

Music evolves as composers, performers, and consumers favor some musical variants over others. To investigate the role of consumer selection, we constructed a Darwinian music engine consisting of a population of short audio loops that sexually reproduce and mutate. This population evolved for 2,513 generations under the selective influence of 6,931 consumers who rated the loops’ aesthetic qualities. We found that the loops quickly evolved into music attributable, in part, to the evolution of aesthetically pleasing chords and rhythms. Later, however, evolution slowed. Applying the Price equation, a general description of evolutionary processes, we found that this stasis was mostly attributable to a decrease in the fidelity of transmission. Our experiment shows how cultural dynamics can be explained in terms of competing evolutionary forces.

You can find examples of the evolved music at http://darwintunes.org/ where they’ve now got up to 3,500 generations, and you can also take part in the study. The ‘selective influence’ is just asking people to rate the clips – do they like them or not? The ‘sexual reproduction’ is done by splitting and mixing the clips with each other to simulate chromosome mixing (sex is good for mixing up genes), and the ‘mutation’ is introducing a bit of random variation. So that looks like a nice model of reproductive selection, and what comes out sounds more and more like music as you go down the generations. In fact, there may even be new species evolving: a tweet today says: “Amazing stuff on the main channel right now – a whole new phenotype has emerged – inter-loop chord changes and more!” (Yes, you can follow them on twitter at darwintunes).

Well, that’s fascinating and fun but as an old folky I thought ‘Duh!: I thought everyone knew that music evolved.’ A long established theory of the development of traditional music is one of evolution with variation provided by imperfect recall and bits of musical innovation, and selection provided by people’s preference for what they would like to hear and play again, or maybe just by what sticks in memory.

Here’s the definition from the International Folk Music Council (no, I didn’t know there was one of those, either) in 1954:

..folk music is the product of a musical tradition that has been involved in the process of oral transmission. The factors that shape the tradition are i) continuity which links the present with the past; ii) variation which springs from the creative impulse of the individual or group; iii) selection by the community, which determines the form of forms in which the music survives. (Quoted in Lloyd 1975, p15)

Cecil Sharp said much the same kind of thing in 1920:

…the most typical qualities of the folk-song have been laboriously acquired during its journey down the ages, in the course of which its individual angles and irregularities have been rounded and smoothed away just as the pebble on the seashore has been rounded by the action of the waves; that the suggestions, unconsciously made by individual singers, have at every stage of the evolution of the folk-song been weighed and tested by the community, and accepted or rejected by their verdict; and the life history of the folk-song has been one of continuous growth and development, always tending to approximate the form which should be at once congenial to the taste of the community, and expressive of its feelings, aspirations, and ideals. (p. viii)

Sharp was looking it from the point of view of National Song. Lloyd, a Marxist, uses a different framework:

..the formulation is valuable for its clear suggestion of the vital dialectic of folksong creation, that is, the perpetual struggle for synthesis between the collective and individual, between tradition and innovation, between what is received from the community and what is supplied out of personal fantasy, in short, the blending of continuity and variation. (Lloyd, 1975, p16).

Gerould points out in The Ballad of Tradition (1932, 1957) that this process can also produce a range of equally admirable (in his terms: equally viable, for the evolutionary argument) variants. He does want to bring artistic judgement and ability into it:

the existence of many variants, both melodic and contextual, which are manifestly not due to haphazard, undirected substitution for what has been forgotten shows a widespread power of musical and poetic expression (p183)

…and I guess that’s fair enough. What Mississippi John Hurt or Harry Cox brought to the tradition is probably a step which goes beyond natural selection.

It also seems to me that the biological idea of hybrid vigour is shown when different musical traditions cross: what happened when Scotch-Irish ballads met African-derived music in the Appalachians*, or Toumani Daibaté (and others) combining the power of West African classical music with other traditions**.

A nice modern summary comes from the blogger The Irate Pirate in a post on his Wrath of the Grapevine blog (http://grapewrath.blogspot.co.uk/2009_03_01_archive.html, 2009)

Like most musics, I suppose, the more you listen to folk music the more you develop a taste for it. But part of the fascination that’s particular to folk music is that you’ll hear bits and pieces of one song that you could have sworn you heard in a completely different song. And you’d be right. Because folk music is an evolved music, and like humans & chimpanzees, there are uncanny similarities lurking just below the surface that point to some invisible, unknowable ancestral precedent. And, like all things subject to evolution by natural selection, the essential parts are maintained and the extraneous, inconsequential bits fall aside. What this means in terms of folk music, particularly these old traditional ballads, is that while a song may be quirky and seemingly obtuse, at some level (often a non-conscious, irrational level), the song is deeply meaningful and helps people to negotiate the trials and uncertainties of this muddled mortal existence.

And, of course, since folksong-evolution is an organic process in an oral tradition, sometimes bits and pieces get lost along the way and we’re left with only fragments (you could say this too is a product of natural selection: the part that remains is that which is most memorable). And since it is sung by people who weren’t professional musicians, it had to relate to things that everyday people could relate to, rather than abstruse musical concepts and the self-indulgent wankery that professional artists are susceptible to. The universal subjects are thus revealed: love, death, nature, heartbreak, childhood, remorse, dream/spiritual encounters, and leaving home. These themes can be found recurring in folk music and most great narrative art across time, from Homer to Shakespeare to Stan Brackage. It’s as if these subjects keep coming back because they’re the moments in our lives that stay with us, and we need songs & stories like these to help mark those moments and distill meaning from them.

So, the process that produced the Lowlands of Holland or the Leaves of Life is rather similar to the process that produced the cheetah or the kingfisher (and the warthog and the platypus, to be fair). It’s not surprising that traditional music is so good.

References
GeroulD, G.H. (1932, 1957) The Ballad of Tradition London: Galaxy, OUP

Lloyd, A.L. (1975) Folk Song in England St Albans: Paladin (orig. publ. Lawrence & Wishart, 1967

MacCallum, Robert M, Matthias Mauch, Austin Burt, & Armand M. Leroi (2012) Evolution of music by public choice, PNAS, no paper version yet
Available at: http://www.pnas.org/content/early/2012/06/12/1203182109.full.pdf

Sharpe, Cecil (1920) English Folk Songs, 2nd ed Novello; London

* Here’s Clarence Ashley doing CooCoo bird (music doesn’t start until 3.30):

**TD with the AfroCubism band:

..and playing Cantelowes:

How did humans evolve to be musical?

I just came across interesting stuff relating to two questions about music and evolution. How did humans evolve to be musical? and How does music evolve?

For this post: How did humans evolve to be musical?

There’s a paper by Geoffrey Miller (no relation) Evolution of human music through sexual selection (ftp://ftp.repec.org/RePEc/els/esrcls/draftfin.pdf), which works through the idea being musical and producing music might give the mating advantage, and so evolve through sexual selection.

One thing I like about this paper is that it carefully works through the mechanisms and criteria for thinking that of behaviour or characteristic can be evolutionarily selected, rather than just making up a sort-of convincing story that some characteristic could be a mating advantage and leaving it at that. It does give you a sort-of convincing story as well:

Consider Jimi Hendrix, for example. This rock guitarist extraordinaire died at the age of27 in 1970, overdosing on the drugs he used to fire his musical imagination. His music output, three studio albums and hundreds of live concerts, did him no survival favours. But he did have sexual liaisons with hundreds of groupies, maintained parallel longterm relationships with at least two women, and fathered at least three children in the U.S., Germany, and Sweden. Under ancestral conditions before birth control, he would have fathered many more. Hendrix’s genes for musical talent probably doubled their frequency in a single generation, through the power of attracting opposite-sex admirers. As Darwin realized, music’s aesthetic and emotional power, far from indicating a transcendental origin, point to a sexual-selection origin, where too much is neverenough. Our ancestral hominid-Hendrixes could never say, “OK, our music’s good enough, we can stop now”, because they were competing with all the hominid-Eric-Claptons, hominid-Jerry-Garcias, and hominid-John-Lennons. The aesthetic and emotional power of music is exactly what we would expect from sexual selection’s arms race to impress minds like ours.

…which is great, but he then goes on to carefully work through the mechanisms of selection to build up quite a convincing argument. He also points out that Darwin suggested much the same idea, though it wasn’t taken up in mainstream evolutionary thought.

It’s quite a long and detailed paper, but I think well worth reading, if only as an example of careful thought that I think is often missing in evolutionary psychology. There’s also a bit later on which I found fascinating about possible runaway effects in sexual selection – the kind of thing which leads to hyper exaggerated characteristics which don’t seem very adaptive, like the enormous antlers of the Irish elk or the peacock’s ludicrous tail. You may be able to think of human equivalents. Miller cites mathematical models for the effect, and notes: “Only when the courtship trait’s survival costs became very high might the runaway effect reach an asymptote.”

The power of the runaway theory is that it can explain the extremity of sexual selection’s outcomes: how species get caught up in an endless arms race between unfulfillable sexual demands and irresistible sexual displays. Most relevant for us, the preferences involved need not be cold-blooded assessments of a mate’s virtues, but can be deep emotions or lofty cognitions. Any psychological mechanism used in mate choice is vulnerable to this runaway effect, which makes not only the displays that it favors more extreme, but makes the emotions and cognitions themselves more compelling. Against the claim that evolution could never explain music’s power to emotionally move and spiritually inspire, the runaway theory says: any emotional or spiritual preferences that influence mate choice, no matter how extreme or subjectively overwhelming, are possible outcomes of sexual selection (cf. Dissanayake, 1992). If music that emotionally moves or spiritually inspires tended to sexually attract as well, over ancestral time, then sexual selection can explain music’s appeal at every level.

Although I’m usually very suspicious of evolutionary explanations of psychological phenomena (mainly because they often seem to me to be based on sloppy evolutionary theory), I think Miller makes a good case. There is one thing that worries me, though. The explanation is based on the mate selection, which is Miller says is primarily females selecting males. The peacock and Irish elk examples show characteristics developed in males than females. So this looks like an explanation for why human males develop musicality and the ability to produce music, while human females need only develop musicality – the ability to appreciate the music that males are producing to improve their chances of being selected. So where’s the explanation for women’s musical skills? Many of my favourite musicians, and most of my favourite singers, are women. Is this musical skill an epiphenomenon? Just a matter of gene leakage from the male-selected characteristic?

The other question is how does music evolve? See the next post for that.

Reference:
Miller, G. F. (2000). Evolution of human music through sexual selection. In N. L. Wallin, B. Merker, & S. Brown (Eds.), The Origins of Music, MIT Press.