Why music? From The Economist print edition
December 18, 2008 http://www.economist.com/printedition/displayStory.cfm?Story_ID=12795510
Biologists are addressing one of humanity’s strangest attributes, its all-singing, all-dancing culture
“IF MUSIC be the food of love, play on, give me excess of it.” And if not?
Well, what exactly is it for? The production and consumption of music is a
big part of the economy. The first use to which commercial recording, in the
form of Edison’s phonographs, was to bring music to the living rooms and
picnic tables of those who could not afford to pay live musicians. Today,
people are so surrounded by other people’s music that they take it for
granted, but as little as 100 years ago singsongs at home, the choir in the
church and fiddlers in the pub were all that most people heard.
Other appetites, too, have been sated even to excess by modern business.
Food far beyond the simple needs of stomachs, and sex (or at least images of
it) far beyond the needs of reproduction, bombard the modern man and woman,
and are eagerly consumed. But these excesses are built on obvious appetites.
What appetite drives the proliferation of music to the point where the
average American teenager spends 11⁄2-21⁄2 hours a day—an eighth of his waking
life—listening to it?
Well, that fact—that he, or she, is a teenager—supports one hypothesis about
the function of music. Around 40% of the lyrics of popular songs speak of
romance, sexual relationships and sexual behaviour. The Shakespearean
theory, that music is at least one of the foods of love, has a strong claim
to be true. The more mellifluous the singer, the more dexterous the harpist,
the more mates he attracts.
A second idea that is widely touted is that music binds groups of people
together. The resulting solidarity, its supporters suggest, might have
helped bands of early humans to thrive at the expense of those that were
Both of these ideas argue that musical ability evolved specifically—that it
is, if you like, a virtual organ as precisely crafted to its purpose as the
heart or the spleen. The third hypothesis, however, is that music is a cross
between an accident and an invention. It is an accident because it is the
consequence of abilities that evolved for other purposes. And it is an
invention because, having thus come into existence, people have bent it to
their will and made something they like from it.
She loves you
Shakespeare’s famous quote was, of course, based on commonplace observation.
Singing, done well, is certainly sexy. But is its sexiness the reason it
exists? Charles Darwin thought so. Twelve years after he published “On the
Origin of Species”, which described the idea of natural selection, a second
book hit the presses. “The Descent of Man and Selection in Relation to Sex”
suggested that the need to find a mate being the pressing requirement that
it is, a lot of the features of any given animal have come about not to aid
its survival, but to aid its courtship. The most famous example is the tail
of the peacock. But Darwin suggested human features, too, might be sexually
selected in this way—and one of those he lit on was music.
In this case, unlike that of natural selection, Darwin’s thinking did not
set the world alight. But his ideas were revived recently by Geoffrey
Miller, an evolutionary biologist who works at the University of New Mexico.
Dr Miller starts with the observations that music is a human universal, that
it is costly in terms of time and energy to produce, and that it is, at
least in some sense, under genetic control. About 4% of the population has
“amusia” of one sort or another, and at least some types of amusia are known
to be heritable. Universality, costliness and genetic control all suggest
that music has a clear function in survival or reproduction, and Dr Miller
plumps for reproduction.
One reason for believing this is that musical productivity—at least among
the recording artists who have exploited the phonograph and its successors
over the past hundred years or so—seems to match the course of an
individual’s reproductive life. In particular, Dr Miller studied jazz
musicians. He found that their output rises rapidly after puberty, reaches
its peak during young-adulthood, and then declines with age and the demands
As is often the case with this sort of observation, it sounds unremarkable;
obvious, even. But uniquely human activities associated with
survival—cooking, say—do not show this pattern. People continue to cook at
about the same rate from the moment that they have mastered the art until
the moment they die or are too decrepit to continue. Moreover, the anecdotal
evidence linking music to sexual success is strong. Dr Miller often cites
the example of Jimi Hendrix, who had sex with hundreds of groupies during
his brief life and, though he was legally unmarried, maintained two
long-term liaisons. The words of Robert Plant, the lead singer of Led
Zeppelin, are also pertinent: “I was always on my way to love. Always.
Whatever road I took, the car was heading for one of the greatest sexual
encounters I’ve ever had.”
Another reason to believe the food-of-love hypothesis is that music fulfils
the main criterion of a sexually selected feature: it is an honest signal of
underlying fitness. Just as unfit peacocks cannot grow splendid tails, so
unfit people cannot sing well, dance well (for singing and dancing go
together, as it were, like a horse and carriage) or play music well. All of
these activities require physical fitness and dexterity. Composing music
requires creativity and mental agility. Put all of these things together and
you have a desirable mate.
Improve your singing…
A third reason to believe it is that music, or something very like it, has
evolved in other species, and seems to be sexually selected in those
species, too. Just as the parallel evolution of mouse-like forms in
marsupial and placental mammals speaks of similar ways of life, so the
parallel evolution of song in birds, whales and gibbons, as well as humans,
speaks of a similar underlying function. And females of these animals can be
fussy listeners. It is known from several species of birds, for example,
that females prefer more complex songs from their suitors, putting males
under pressure to evolve the neurological apparatus to create and sing them.
And yet, and yet. Though Dr Miller’s arguments are convincing, they do not
feel like the whole story. A man does not have to be gay to enjoy the music
of an all-male orchestra, even if he particularly appreciates the soprano
who comes on to sing the solos. A woman, meanwhile, can enjoy the soprano
even while appreciating the orchestra on more than one level. Something else
besides sex seems to be going on.
The second hypothesis for music’s emergence is that it had a role not just
in helping humans assess their mates, but also in binding bands of people
together in the evolutionary past. Certainly, it sometimes plays that role
today. It may be unfashionable in Britain to stand for the national anthem,
but two minutes watching the Last Night of the Proms, an annual music
festival, on television will serve to dispel any doubts about the ability of
certain sorts of music to instil collective purpose in a group of
individuals. In this case the cost in time and energy is assumed to be
repaid in some way by the advantages of being part of a successful group.
The problem with this hypothesis is that it relies on people not cheating
and taking the benefits without paying the costs. One way out of that
dilemma is to invoke a phenomenon known to biologists as group selection.
Biologically, this is a radical idea. It requires the benefits of solidarity
to be so great that groups lacking them are often extinguished en bloc.
Though theoretically possible, this is likely to be rare in practice.
However, some researchers have suggested that the invention of weapons such
as spears and bows and arrows made intertribal warfare among early humans so
lethal that group selection did take over. It has been invoked, for example,
to explain the contradictory manifestations of morality displayed in battle:
tenderness towards one’s own side; ruthlessness towards the enemy. In this
context the martial appeal of some sorts of music might make sense.
Robin Dunbar of Oxford University does not go quite that far, but unlike Dr
Miller he thinks that the origins of music need to be sought in social
benefits of group living rather than the sexual benefits of seduction. He
does not deny that music has gone on to be sexually selected (indeed, one of
his students, Konstantinos Kaskatis, has shown that Dr Miller’s observation
about jazz musicians also applies to 19th-century classical composers and
contemporary pop singers). But he does not think it started that way.
…and your grooming
Much of Dr Dunbar’s career has been devoted to trying to explain the
development of sociality in primates. He believes that one of the things
that binds groups of monkeys and apes together is grooming. On the face of
it, grooming another animal is functional. It keeps the pelt clean and
removes parasites. But it is an investment in someone else’s well-being, not
your own. Moreover, animals often seem to groom each other for far longer
than is strictly necessary to keep their fur pristine. That time could, in
principle, be used for something else. Social grooming, rather like sexual
selection, is therefore a costly (and thus honest) signal. In this case
though, that signal is of commitment to the group rather than reproductive
Dr Dunbar thinks language evolved to fill the role of grooming as human
tribes grew too large for everyone to be able to groom everyone else. This
is a controversial hypothesis, but it is certainly plausible. The evidence
suggests, however, that the need for such “remote grooming” would arise when
a group exceeds about 80 individuals, whereas human language really got
going when group sizes had risen to around 140. His latest idea is that the
gap was bridged by music, which may thus be seen as a precursor to language.
The costliness of music—and of the dancing associated with it—is not in
doubt, so the idea has some merit. Moreover, the idea that language evolved
from wordless singing is an old one. And, crucially, both singing and
dancing tend to be group activities. That does not preclude their being
sexual. Indeed, showing off to the opposite sex in groups is a strategy used
by many animals (it is known as lekking). But it may also have the function
of using up real physiological resources in a demonstration of group
By side-stepping the genocidal explanations that underlie the classical
theory of group selection, Dr Dunbar thinks he has come up with an
explanation that accounts for music’s socially binding qualities without
stretching the limits of evolutionary theory. Whether it will pass the
mathematical scrutiny which showed that classical group selection needs
genocide remains to be seen. But if music is functional, it may be that
sexual selection and social selection have actually given each other a
The third hypothesis, though, is that music is not functional, and also that
Dr Dunbar has got things backwards. Music did not lead to language, language
led to music in what has turned out to be a glorious accident—what Stephen
Jay Gould called a spandrel, by analogy with the functionless spaces between
the arches of cathedrals that artists then fill with paintings. This is what
Steven Pinker, a language theorist at Harvard, thinks. He once described
music as auditory cheesecake and suggested that if it vanished from the
species little else would change.
Dr Pinker’s point is that, like real cheesecake, music sates an appetite
that nature cannot. Human appetites for food evolved at a time when the
sugar and fat which are the main ingredients of cheesecake were scarce. In
the past, no one would ever have found enough of either of these energy-rich
foods to become obese, so a strong desire to eat them evolved, together with
little limit beyond a full stomach to stop people eating too much. So it is
with music. A brain devoted to turning sound into meaning is tickled by an
oversupply of tone, melody and rhythm. Singing is auditory masturbation to
satisfy this craving. Playing musical instruments is auditory pornography.
Both sate an appetite that is there beyond its strict biological need.
Of course, it is a little more complicated than that. People do not have to
be taught to like cheesecake or sexy pictures (which, in a telling use of
the language, are sometimes also referred to as “cheesecake”). They do,
however, have to be taught music in a way that they do not have to be taught
Words and music
Aniruddh Patel, of the Neurosciences Institute in San Diego, compares music
to writing, another widespread cultural phenomenon connected with language.
True language—the spoken languages used by most people and the gestural
languages used by the deaf—does not have to be taught in special classes.
The whole of a baby’s world is its classroom. It is true that parents make a
special effort to talk to their children, but this is as instinctive as a
young child’s ability (lost in his early teens) to absorb the stuff and work
out its rules without ever being told them explicitly.
Learning to write, by contrast, is a long-winded struggle that many fail to
master even if given the opportunity. Dyslexia, in other words, is common.
Moreover, reading and writing must actively be taught, usually by
specialists, and evidence for a youthful critical period when this is easier
than otherwise is lacking. Both, however, transform an individual’s
perception of the world, and for this reason Dr Patel refers to them as
In difficulty of learning, music lies somewhere in between speaking and
writing. Most people have some musical ability, but it varies far more than
their ability to speak. Dr Patel sees this as evidence to support his idea
that music is not an adaptation in the way that language is, but is,
instead, a transformative technology. However, that observation also
supports the idea that sexual selection is involved, since the whole point
is that not everyone will be equally able to perform, or even to learn how
to do so.
Do they know it’s Christmas?
What all of these hypotheses have in common is the ability of music to
manipulate the emotions, and this is the most mysterious part of all. That
some sounds lead to sadness and others to joy is the nub of all three
hypotheses. The singing lover is not merely demonstrating his prowess; he
also seeks to change his beloved’s emotions. Partly, that is done by the
song’s words, but pure melody can also tug at the heart-strings. The chords
of martial music stir different sentiments. A recital of the Monteverdi
Vespers or a Vivaldi concerto in St Mark’s cathedral in Venice, the building
that inspired Gould to think of the non-role of spandrels, generates emotion
pure and simple, disconnected from human striving.
This is an area that is only beginning to be investigated. Among the
pioneers are Patrik Juslin, of Uppsala University, and Daniel Vastfjall, of
Gothenburg University, both in Sweden. They believe they have identified six
ways that music affects emotion, from triggering reflexes in the brain stem
to triggering visual images in the cerebral cortex.
Such a multiplicity of effects suggests music may be an emergent property of
the brain, cobbled together from bits of pre-existing machinery and then, as
it were, fine-tuned. So, ironically, everyone may be right—or, at least
partly right. Dr Pinker may be right that music was originally an accident
and Dr Patel may be right that it transforms people’s perceptions of the
world without necessarily being a proper biological phenomenon. But Dr
Miller and Dr Dunbar may be right that even if it originally was an
accident, it has subsequently been exploited by evolution and made
Part of that accident may be the fact that many natural sounds evoke emotion
for perfectly good reasons (fear at the howl of a wolf, pleasure at the
sound of gently running water, irritation and mother-love at the crying of a
child). Sexually selected features commonly rely on such pre-existing
perceptual biases. It is probably no coincidence, for instance, that
peacocks’ tails have eyespots; animal brains are good at recognising eyes
because eyes are found only on other animals. It is pure speculation, but
music may be built on emotions originally evolved to respond to important
natural sounds, but which have blossomed a hundred-fold.
The truth, of course, is that nobody yet knows why people respond to music.
But, when the carol singers come calling, whether the emotion they induce is
joy or pain, you may rest assured that science is trying to work out why.