Although McNeill’s research focuses on the motoric aspects of synchronized movement, he too feels that music was the guiding and binding force behind organizing this cooperation. Work songs (“Whistle While You Work,” “Let’s Work Together,” “Hard Work”) do help to pass the time, and may well be a comfort to those singing them, but this is not their fundamental use—primarily, they exist to coordinate movement and cooperative undertakings, to imbue participants with a sense of shared purpose. Track lining songs are special cases of music that unified manual labor by their heavy rhythmic component (one-two-three-heave!). They combined the ancient uses of song with more modern, entertaining features, such as lyrics that often insulted things like the eyesight of the track liner or even the parentage of the crew foreman. Chain gang songs may also fall into this category (when the work being done required synchronous movement) or into the category of comfort, as they helped chained workers to pass the time and increase feelings of kinship with their fellow prisoners.
Synchronized singing and dancing did more than just facilitate the building of large-scale civic structures. They helped build political structures as well. Frictions within a group could be smoothed out by promoting feelings of togetherness. Without explicitly requiring the prelinguistic version of an apology, the strong emotional bonds created by synchronized music-dance allowed both parties to save face and to set their differences aside.
Evolution may have selected those individuals who could settle disputes in nonviolent ways such as music-dance. At a neural level, we now know that the hypothalamus, amygdala, motor cortex, and cerebellum are linked both to movement and to emotion. The basis for this linking goes to the heart of why our ancestors needed to move in the first place: to find food, to escape dangers, and to find mates. All three of these activities are necessary for life, and evolution created links between movement and motivation centers, as opposed to color vision or spatial cognition neural circuits, which are not as closely linked to motivation.
What we call emotions are nothing more than complex neurochemical states in the brain that motivate us to act. Emotion and motivation are thus intrinsically linked to each other, and to our motor centers. But the system can work in the other direction, because most neural pathways are bi-directional. In addition to emotions causing us to move, movement can make us feel emotional. To a neutral observer, synchronized dance appears to be the result of a close relationship between the participants. To the participants themselves, although it may not begin this way, it typically ends up engendering strong feelings of sympathy, caring, and affection. Petr Janata, a neuroscientist and musician, described the strength of these bonds this way: “There are times when I would rather make music and dance with my wife than make love with her—the former can be a more intimate or at least a different type of intimate connection.”
Those who march, either in military units or college marching bands, report exhilaration from the activity. Although to an outsider marching drills may seem repetitive and boring, the participants often experience a kind of Zen state of focused attention, readiness, and excitement combined with an almost paradoxical sense of calm—a state called
flow
by the psychologist Mihaly Csikszentmihalyi. A principle of evolution is that in general, if something feels good, evolution must have made it so—evolution must have provided a reward mechanism for synchronized movement and music-making, in the same way that evolution provided mechanisms of reward when we eat and have sex.
William McNeill recalls his days in the infantry:
What I remember now, years afterwards, is that I rather liked strutting around, and so, I feel sure, did most of my fellows. Marching aimlessly about on the drill field, swaggering in conformity with prescribed military postures, conscious only of keeping in step so as to make the next move correctly and in time somehow felt good. Words are inadequate to describe the emotion aroused by the prolonged movement in unison that drilling involved. A sense of pervasive well-being is what I recall; more specifically, a strange sense of personal enlargement; a sort of swelling out, becoming bigger than life, thanks to participation in collective ritual.
In his insightful history of synchronized military drill, McNeill cites Maurice of Orange, Sun Tzu, Thucydides, and other sources about the effectiveness of marching and the sweeping changes it brought to the battlefield. Some evolutionary theorists might argue that these accounts are too recent (evolutionarily speaking) to be relevant to natural selection, for the good feelings that accompanied such exercises to have been shaped by natural selection. But where threats to life are concerned, natural selection can work its magic in just a few generations. Suppose there are some people who, by virtue of random mutation, enjoy eating dirt. An epidemic of a fatal virus sweeps the world, attacking hundreds of millions of people. It turns out that a particular compound, found only in dirt, kills the virus. Those people who eat dirt would survive and nearly everyone else could be wiped out within only one or two generations.
What we call
instinct
in humans and animals is often nothing more than the product of natural selection at work. Consider house cats. Cats kick dirt or sand or whatever is nearby over their excrement. But it is unlikely that they understand the germ theory of disease and are covering their excrement to minimize contagion. Instead, some ancestral cats had a genetic mutation that triggered the release of certain reinforcing neurochemicals (let’s call them “happy juice”) when they kicked after excreting. The cats with this mutation were less likely to get sick or to spread disease to their offspring, facilitating this mutation’s rapid spread through the genome.
By extension, humans who enjoyed singing, dancing, and marching together so much that they were drawn to it, attracted to it, and practiced it for thousands of hours were those who were the victors in any battles in which such drill conferred an advantage. The strong emotional, even neurochemical pleasure that resulted from synchronized movement may well have had a prehistoric antecedent. Our hunter-gatherer ancestors may have danced around the campfire before and after the hunt. By rehearsing their movements, they gained precision in their actions and were thus more likely to succeed. And taking down a large swift mammal with handheld tools likely required the coordinated movement of many accomplices. Modern army drill is probably an extension of this prehistoric behavior. Music traditionally has been characterized not only by sound but by
action,
and by
interaction
among makers of music-dance.
Humans around the world report not just strong emotional bonding from synchronized, coordinated movement together, but feelings of a spiritual nature—a sense of there being a collective consciousness, the presence of a superior being, or an unseen world that is larger than what we immediately experience. The cognitive psychologist Jamshed Bharucha suggests an explanation for these feelings. The sense of group agency or collective consciousness that one feels when synchronized with others is more than an exhilarating feeling, he says. We feel this exhilaration, which comes from the neurochemical activity described above, and that leads the brain to seek a cause. Attribution—particularly causal attribution—is an automatic and compelling tendency of the brain. In fact, we can’t not attribute causes. As we sense a change in our emotional state, we look around to see what’s going on in the world that could explain our mood. In the case of group synchrony, we look around us and see all these other people dancing and singing with joy and excitement. In this way, the strange feeling (from the neurochemicals) becomes attributed to something beyond oneself. That’s why, in addition to the other advantages of group cohesion mentioned, religions make use of synchronization: It actually enhances the belief in a cause beyond oneself. So it’s more than just a good feeling; auditory and motor synchronization can lead to beliefs in forces that transcend the individual, such as societies.
Music and coordinated movement were thus a way of creating meaningful social bonds for these four activities just reviewed: waging war, defending against attack, hunting prey, and forming work crews. A fifth and crucial use of music was for easing tensions within the larger social groups that were forming—group cohesion. Here, music can be traced back even before the emergence of our own species,
Homo sapiens sapiens,
to tens of thousands of years before with a common ancestor,
Homo erectus
. Around the time that
Homo
became bipedal and erect, they left the relatively safe cover of tree living to live on the savannah; the principal advantage was a greatly increased supply of food as
Homo
became hunters, but there were disadvantages as well to be weighed. As Mithen notes:
Away from the cover of trees, safety can only be found in numbers. . . . There is, however, a cost: social tensions leading to conflicts can arise when large numbers have to live continuously in close proximity to one another.
Easing these social tensions was not trivial. Among nonhuman primates, this is generally accomplished by grooming one another (picking nits and cleaning the hair of a friend); in fact, the closeness of a relationship between two primates can often be determined simply by the amount of time one spends grooming the other. But with the increased size of living groups—which was necessary for mutual protection—physical grooming of all one’s friends and allies becomes impossible. The Oxford anthropologist Robin Dunbar proposed the vocal grooming hypothesis as the origin of vocal communication—the idea that hominids developed vocal communication (music or language) in order to indicate their cooperation and alliance with larger numbers of group members at once.
All over the world and in disparate cultures, human singing is present in two broad styles or forms: strict synchrony and alternation. In strict synchrony, the singers lock their vocalizations in with one another, such as we do in songs like “Happy Birthday” or most national anthems. This requires the ability to anticipate what is coming next in the song (combining cognitive operations of memory in the hippocampus and prediction in the frontal lobes), and then to create what neuroscientists call a
motor action plan
—a specific set of instructions sent to the motor cortex to enable one to sing, drum, or otherwise move the body in time with what others are doing. Part of the evidence that
prediction
processes are involved when we synchronize our singing, hand clapping, or other musical gestures to those of a group is in the small, microtiming errors people make in trying to synchronize: Far more often than not, they are
early
in matching others’ musical behavior. This tells us that they’re not waiting to hear the next beat before they try to play it; rather, they’re anticipating when it will come and preparing a response before it happens. The coordination of activity in these three brain regions (hippocampus, motor cortex, and predictive centers in frontal lobes) would be dependent on the larger prefrontal cortex (than other hominids) that humans evolved.
Alternation occurs when some members of the group deliberately don’t synchronize with others, singing either in a round (as when children sing “Row Row Row Your Boat” and some start at a different time than others) or when singing a “call and response” pattern such as in the children’s campfire song “Sippin’ Cider Through a Straw.” Call and response is often found in American gospel music, and is based on an ancient African tradition. Indeed, in sub-Saharan African cultures in particular, this style is considered emblematic of a democratic participation in the music. Call and response is also found in traditional Indian classical music (where it is called
jugalbandi
or
sawaal-javaab
in North Indian classical music), in Latin American music (where it is called
coropregon)
, and in European classical music (
antiphony).
Alternation in particular requires perspective taking (the first of the three components of the musical brain), and can be seen as an exercise for or predecessor to other more utilitarian cooperative activities. Those individuals who were better able to predict the behavior of others because they could “read their minds” would have had a competitive advantage within the group.
But understanding why it is music and not something else that causes these strong feelings of social bonding remains partly a mystery. Dunbar (and others who followed, including Dean Falk) made the case for why aural bonding would be more efficient than one-on-one physical bonding through grooming behaviors (or through sexual activity as is done by bonobos to promote bonding). Recall that evolution doesn’t invent new features from scratch; it doesn’t design from whole cloth. Rather, evolution uses structures already in place. Communicative calls and signals were already ubiquitous among the repertoires of nonhuman primates—certain sounds indicated particular types of dangers, the presence of food, and so on. Making such sounds in synchrony would be a clear indication that the group members were paying attention to each other and had a common interest. Among such group vocalizers, those that happened upon a way to induce feelings of happiness, safety, and security in their group mates would have an advantage—these early politicians could cause others to cooperate more with them because they were the source of good feelings.
In a larger context, individuals with social skills would receive many benefits—they would know how and when to get help from others, whom to fight with, whom to trust, and whom to avoid. This emotional intelligence would have given them power over others. Today, in contemporary society, we regard music as a form of emotional communication—perhaps the best one we know. There is no reason to suspect that music functioned differently—although the music itself may have been very different—thousands of years ago. Early humans may have used music to broadcast their own emotional states to others, as well as for the (political) purposes of calming, energizing, organizing, and inspiring.