Music, Evolution & Sex
Outline for presentation
Music comes in many varieties. I’m going to focus on just one kind: vocal.
[Sign] Warning: Opera Content
The reasons for this will become fully apparent as I unfurl my argument, but for now, let me just say that the human voice is to many people, including me, by far the most beautiful and moving of instruments.
Ten years ago, I gave a presentation on world music. I had selections from every continent, and given enough time I could have come up with a sample from every culture. Back then, however, I had not one word to say about the relation of music to evolution. It was just mystery to me why so many kinds of beautiful music exist in the world, and why they move us so deeply.
[La Traviata no 5]
Anybody find that moving? I'm glad to know that I'm not the only one. But why? In the New York Times, science journalist Nicolas Wade writes, "Music is still a mystery, a tangle of culture and built-in skills that researchers are trying to tease apart. No one really knows why music is found in all cultures, why most known systems of music are based on the octave, why some people have absolute pitch and whether the brain handles music with special neural circuits or with ones developed for other purposes. Recent research, however, has produced a number of theories about the brain and music."
Some big thinkers think that music is just an accident. The philosopher George Santayana said, "Music is essentially useless." Of course, he then added, "as is life," so maybe he was just having a bad day. Even some of the biggest names in evolution have had hissy fits over evolutionary explanations of music. "As far as biological cause and effect is concerned, music is useless" Stephen Pinker of MIT said, adding that it is "auditory cheesecake." The late Stephen Jay Gould went further, declaring that all evolutionary attempts to understand distinctively human abilities such as music were, ""foolish," "fatuous," "pathetic," and "egregiously simplistic," since he, Stephen Jay Gould, knew that things like music were just “spandrels” -- "nonadaptive side consequences" resulting from our vast quantity of "surplus brain tissue."
[Sign] [He said a lot of dumb things.]
Well, maybe. But more likely they are just looking at the wrong part of evolution.
I'd like to explore some of those answers this evening, with a particular emphasis on one idea: that vocal music developed as fitness indicator in the context of sexual selection. As I present, I invite you to be skeptical and critical, but at the same time, to sit back and enjoy the music.
So here's one of the most interesting and dangerous things about humans. Our brains have evolved far beyond the needs of mere survival – at least compared with our primate cousins. Maybe too far for our own good. We can think and communicate in symbolic language, which allows us create ideologies that join vast tribes in deadly hatred of other vast tribes. We can do math, which, among other things, allows us to calculate the ballistic trajectory of an ICBM carrying nuclear warheads. Kurt Vonnegut makes this point in his novel Galápagos, in which after nearly destroying our world, the human brain goes into retro-evo, and we wind up a simple, happy, aquatic species. But we can also make music, which is as harmless and pleasurable an activity as humans have ever created.
Again, why? It's a question that has yet to be convincingly answered. It may be that music is a gift from God, but if so that simply has to be taken on faith. It may be that it’s a sidetrack of our linguistic abilities. The ability to communicate complex messages clearly has survival value; the ability to embroider them with music does not. But if oral language requires a highly variable and responsive larynx, then it’s not surprising that complex music can also issue forth from the vocal chords. Maybe music just happens.
Nothing I'm going to say absolutely rules out those possibilities, but they are dead ends. They’re pretty much the same as saying that music is a mystery. Besides, I have a hunch that there’s more to music than either divine grace or survival.
I'm inclined to agree with those scientists who believe that evolution explains it. Not the kind of evolution we're used to thinking about, however. I’m the first to agree that music has little if any survival value. You may whistle past the graveyard, or sing a merry tune, but that won't keep the wolf from the door.
No, the kind of evolution I'm talking about comes from Darwin's other theory: sexual selection. This arose in his second major book on evolution, generally known as The Descent of Man. In Victorian times, however, titles ran a good deal longer than they do today, and the full title of this book is worth knowing: The Descent of Man and Selection in Relation to Sex.
Those of you who've been hanging in the Forum for awhile know that I love to explain things. Let me take just a couple of minutes to explain about sexual selection. In a nutshell, it's this: males show off, and females pick the ones they like best.
Here's what Darwin had to say: "the habitual … preference by the female of the more attractive males would almost certainly lead to their modification; and such modifications might in the course of time be augmented to almost any extent, compatible with the existence of the species."
Victorian language aside, in many ways, in many ways this is easier to grasp than Darwin's theory of natural selection. That's because it's just like domestic breeding.
Humans carefully scrutinize the litters of their domestic animals and then breed them for certain desirable traits. Think about dogs. The science of phylogenetics shows that dogs evolved from wolves sometime in the last 100,000 years. But what's more interesting, for our purposes, is that dozens of breeds of dogs, from Chihuahuas to Irish wolfhounds to pitbulls, have developed through selective breeding in just the last few thousand years.
Sexual selection is a lot like that, except that instead of third parties doing the selection, it's the females of the species. But how do they choose? And why?
What Darwin didn't get was that just as traits were heritable, so were preferences for traits. If peacocks grow ornate tails, it's not because we appreciate them, but because peahens have genes that cause them to prefer big and ornate tails.
Why a big, colorful tail, though? For decades, biologists thought that the explanation was runaway sexual selection, with female preferences driving male competition to ever greater extravagance. There's some truth in that, but it can't be the whole story. Just as dog fanciers have bred dachshunds to the point where their backs are liable to fracture, sexual selection can force male bear traits that actually run counter to their individual survival. This tension between survival value and sexual attractiveness seems bizarre, and for a long time scientists were stumped. Let's pause to note that until the 1970's nearly all the scientists investigating these questions were men, and among their prejudices was a widespread view that women were capricious, arbitrary, and just plain silly.
[Sign] "Direct thought is not an attribute of femininity. In this, women are centuries behind man."
-- Thomas Edison
"Women's intuition is the result of millions of years of not thinking."
-- Rupert Hughes
But the truth turns out to be very different. In K-selected species like ours, females give birth to just a few offspring at a time, so they have a very strong incentive to choose the father of their children carefully. And in fact females force males to do all sorts of tiresome things to prove themselves worthwhile. It may seem wacky to demand that peacock grow a huge and colorful tail, or that a buck grow enormous antlers, but an evolutionary logic lies behind them.
It's this. As every woman can testify, when it comes to sex, males are like Texas salesmen. They will say anything to get their way.
[Sign] [“We know where the weapons of mass destruction are”]
In most species, males convey their promises through fitness displays. Fireflies flash, pigeons strut, and rams butt heads. And how about humans? Can singing be a fitness display? You tell me…
[Nessun Dorma]
To make sense in an evolutionary context, a fitness display has to signal something worth knowing. Standard evolutionary
So females have learned to demand that males display their fitness in ways that can't be faked.
In the early 1970s Israeli biologist Amotz Zahavi named this the handicap principle. Here's the idea. If a male can take on a handicap – something that threatens his survival – and still make it, the evolutionary logic goes, then he must have good genes. This makes sense. After all, sexual ornaments are worthless if they don't represent genuine genetic fitness. Since a female's reproductive capacity is generally much more limited than a male's, it's important to her to spot good genes for her offspring. By good genes, incidentally, we're talking about those that will enable her offspring to ward off disease, predators, and starvation and land a mate with whom to reproduce.
Others have taken Zahavi’s principle and placed it in the context of game theory. That’s a really fascinating subject, but for now all we have to know about game theory is that signals – both true and false – are the key to decisions. As biologist Alan Grafen puts it, what’s important to females is “honest signaling.”
With that in mind, it’s clear that a peacock’s tail signals that here’s a male who is able to get plenty to eat, ward off parasites, and evade predators.
[What more could a peahen want?]
So what do women want? Well, the ability to dunk a basketball or lift a refrigerator clearly impresses some women. But on the whole they value mental abilities more. Could music be an honest signal of both physical and mental ability? Check it out.
[Patter song from Cenerentola]
So why would women care about the ability to pull off a rapid fire patter song like that? What qualities does it evince? Well, mental agility, for one thing. Memory for another. Communicative ability for a third. And to a certain extent intelligence. There is a well established correlation between musical and mathematical abilities.
Would these have been valuable general-purpose assets to pursue in a mate during the Pleistocene era of hunter-gatherer clans wandering over vast territories? Yeah, I think so. (1.8 mya – 12,000 bp)
Evolutionary psychologist Geoffrey Miller, in his fine book The Mating Mind, explains: “To traditional evolutionary psychologists,” Miller observes, “human abilities like music, humor, and creativity do not look like adaptations because they look too variable, too heritable, too wasteful, and not very modular. But these are precisely the features we should expect of fitness indicators” since “sexual choice demanded courtship behavior that stretched the mind’s capacities."
It seems to me highly plausible that music evolved in the context of courtship. It seems highly plausible that it became one of the fitness indicators that women relied on in appraising men. But what I think doesn't count for much. Is there any evidence to back this claim? Not much.
Probably the strongest evidence comes from other animals. From cicadas to humpback whales, songs are the stuff of wooing. Males sing their hearts out to win the hearts of females.
Two other bits: neurological and archaeological
"There is specialization in the brain for the processing of music," notes Harvard neurobiologist Mark Tramo. Not the same circuits as language.
N. Kogan observes that infants have virtually all the musical perception abilities of adults prior to the age of one. In fact, other research shows that infants tend to have perfect pitch, but most lose it as their acquisition of language grows.
Most language abilities are based in the left hemisphere of the typical brain. However, much of musical ability is based in the right hemisphere. That suggests independent evolution.
Finally, and highly speculatively, there is this: homo sapiens has been around for a couple of hundred thousand years, but until very lately he hasn't got much to show for it. Maybe a little campfire, some scraps of clothing, a bit of flint working, but by and large, you don't find much that's distinctively human until about 50,000 years ago. But for at least 10 times that long, hominids of various kinds – including Neanderthals – had been growing big brains. What were they using them for? Not doing Sudoku puzzles, that's for sure. They probably weren't having long discussions either.
Archaeologist Steven Mithen argues that hominids were using their fancy brains and larynxes to produce music long before language as we know it existed. He calls this calls HMMM: Holistic, Multi-Modal, Mimetic.
If we accept that, then we still have to ask, what did they use HMMM for? My guess is that it was mainly LOVE. Just like the cicadas and the whales, men were HMMMing to attract mates. It may even be that their competition to out HMMM each other lead to language. Maybe the first language was the lyrics of the ballad:
Se il nome.
Doesn't have to be hypermasculine. Just beautiful.
But here's a little problem with the idea of music as a fitness display, shouldn't men be better at it than women? Maybe After all, in some other Let's ask Linda Ronstadt.
La Charreada
Music is not a secondary sex characteristic. In this way, it's different from, say bulging muscles or deep voices, which are genetically programmed markers of masculinity. But that doesn't rule it out from having its origin in courtship. The Y chromosome is the smallest of them all, and it can't carry everything. So maybe musical ability, being a complex aspect of the human brain, just couldn't reside on one side of the gender divide. Similarly, the ability to appreciate music is too complex to belong just to women. I'm on really speculative ground here, but what ever the cause, I'm grateful that both men and women can produce and enjoy music.
Finally, I have to remark that whatever the origins of music, it is now a mostly cultural phenomenon, and one that it put to a great range of purposes. Definitely I am not claiming that all music is about sex. Sometimes music is sacred.
[Gregorian chant]
Sometimes, it's just plain fun.
[I am the model of modern major general.]
So, music is not all about sex. It's got all sorts of sacred and profane uses, and sometimes it is just plain beautiful.
Still, I am arguing that music likely has its origin in the never ending struggle of men to win sexual favors, and the never ending struggle of women to pick out a good man from among all the pretenders. So what? you may say. Well, I admit that my conclusion is not a scientific fact, and even if you accept it, the world won't change. But it seems to me that the better we understand ourselves, the better off we are, both individually and as a species. Evolution offers us deep insights into both our aggressive and our creative tendencies. It's important not to get carried away with evolutionary speculation, however. And so, in place of a grand conclusion, I'll let the music carry the message for me:
[Beatles – All you need is love]
Thank you.