Natural selection, then, acted to select for altruism, fidelity, bonding, and those qualities that are all part and parcel of mature love. These would have been important qualities in the formation of the kinds of societies that allowed for large-scale cooperative enterprises such as agriculture, irrigation, construction projects (like grain storehouses), welfare, and courts. With the increased time it took to raise, nurture, and educate offspring, evolution had to find a way to keep the father interested in helping.
Psychologist Martie Haselton argues that love developed as a “commitment device.” In one experiment, she asked people to think about how much they love their partner and then try to suppress thoughts of other people they find sexually attractive. She then had the same people think about how much they sexually desire that same partner and then try again to suppress thoughts about others. Thinking about someone you love was far more effective at suppressing thoughts of others than thinking about someone you lust after—even when it is the same person. Haselton argues that this is just what you’d expect from a neurochemical adaptation to create long-term commitment. Sex plays a role in strengthening commitment too. Most species of mammals engage in sex only during limited times, primarily when the female is fertile. Humans and bonobos are notable exceptions—we have sex even when it will not result in reproduction: during non-fertile times of the month, while the female is already pregnant, and after menopause. Zoologist Desmond Morris suggests that this was to give the male more reason to stick with one female. Add to that the shot of oxytocin that is released during orgasm, and you have a neurochemical recipe for men and women wanting to stay together.
Sex is of course a powerful drive, and implicit in Haselton’s and Darwin’s arguments is that sex in effect masquerades as love—whether we see love as a cultural, psychological, spiritual, or neurochemical invention, it functioned evolutionarily as a way to ensure that the product of sexual reproduction was well cared for. At the level of
society,
love has become more than just looking after one’s offspring, but society itself looking after everyone’s offspring—hence schools, soccer clubs, welfare, Medicare, and courts. In other words, love for one’s partner and children evolved, culturally (and perhaps biologically), into the capacity to love life and fairness, goodness, and equality, and all the ideals we associate with society.
Like religion and love, music itself may be similarly decomposable into the Chomskian two-part system. Many animals produce acoustic signals that
sound
like music to us—think birds and whales, for example. But these animal “songs” almost always lack the ability to indefinitely and infinitely recombine elements according to a hierarchy, and they lack the recursion that characterizes human musics. Interestingly, the newest research shows that while animal musics
don’t
have these properties so closely associated with human music, the animals
can
process sound in this way. In other words, nonhuman species contain the very foundational abilities that were for decades considered unique to human thought; it’s just that they haven’t (yet) learned to use them on their own. In a landmark article, Daniel Margoliash, Howard Nusbaum, and colleagues showed that European starlings can
learn
syntactic recursion. Earlier, Gary Rose found that white-crowned sparrows can assemble an entire song in proper sequence when exposed to only fragments of that song—suggesting that they possess an innate understanding of a syntactical rule for how sparrow songs are constructed. None of this is surprising given the dominant theme of evolution presented in this book—that its products tend to fall along a continuum.
Animal music is purely conveyance—its purpose is to broadcast a limited number of states-of-being. Human music comprises both conveyance and rearrangement. The computational aspect enables us to plan—to contemplate how we want to use music. We use music to convey feelings and concepts we are not necessarily feeling at the present moment. We can decide to
use
music in order to accomplish a particular goal. I can take an element from this song and combine it with that one over there. One of my favorite songs by Rodney Crowell is a song about his favorite song. In “I Walk the Line, (Revisited),” he writes about the first time he heard the famous song by Johnny Cash:
I’m back on board that ’49 Ford in 1956
Long before the sun came up way out in the sticks
Note Rodney’s use of internal rhymes for
board
and
Ford
(and then
before
in the next line), plus the alliteration of
back on board, forty-nine Ford,
and
nineteen fifty-six
. The phrases “back on board ” and “ ’49 Ford ” have the kind of percussive consonant quality that conveys an early rock ’n’ roll feel. The second line, “Long before the sun came up,” establishes the time of day, the young Crowell riding in the backseat at dawn. It also functions metaphorically, referring to this record as coming out during the dawn of rock ’n’ roll. The metaphor is even sweeter to those who know that Sun Records, through its hits with Cash, Elvis Presley, Roy Orbison, and Carl Perkins, is considered by many to be the first and most important rock ’n’ roll record label.
The headlight showed a two rut roadway back up in the pines
First time I heard Johnny Cash sing “I Walk the Line”
In the middle of the song, Johnny himself makes a cameo, singing the famous chorus from that famous song, his booming bass voice seemingly scraping the bottom of the range of human hearing. This sort of embedding of one phrase in another is a hallmark of human language, but turns out to have correlates in other species’ vocalizations as well. Magpies and mockingbirds embed bits and pieces of other birds’ songs in their own. The point is that computational modules in the brain that give us the capacity to do this fall along a continuum across species, but reach their peak in human beings. Jazz players quote other music all the time, a trick they borrowed from the great composers, including Haydn and Mozart, who embedded pieces of other songs into their own. And to my ears, nothing sounds as sweet as Rodney’s music—and wordplay in this song, a moving and loving tribute to memory, to music, and to human creativity.
Human music has hierarchical structure and complex syntax, and we compose within that constraint. Music, like language and religion, contains elements shared with other species and also elements unique to humans. Only humans compose a song for a particular purpose, made up of elements found in other songs. Only humans have the vast repertoire of songs (the average American can readily identify more than one thousand different songs). Only humans have a cultural history of songs that fall within six distinct forms.
It is important, when considering animal music, to distinguish beween musical expression and musical experience. In other words, many animals express themselves in ways that sound musical to us, but are really functioning as conveyance and messages among themselves; there is no evidence that they
experience
music as the aesthetic or creative artform that we do.
It is advisable also to consider that
music
per se is not what evolved, but rather, music comprises components each of which has undergone a specific and probably separate evolutionary trajectory. Pitch, rhythm, and timbre are processed in separate parts of the brain. They come together later during processing, and melody, a higher-order concept, is constructed from these, influenced by changes in any one, or any combination, of the lower-level features. Music as we know it emerged in evolution after these component processes were already in place.
Evolution endowed the musical brain with a perception-production link that most mammals lack. This motor-action-imitation system gives us the ability to take something in one sensory domain and figure out how to create it with another. We
hear
music, then
sing
it. Every song you know how to sing, every word you speak, you reproduce with your own voice based on something you originally heard. Humans (and only a few other species, such as parrots) are able to turn what we hear into what we reproduce vocally. In spite of the high intelligence of mammals, most do not have the capacity to imitate a sound they’ve heard (exceptions include humpback whales, walruses, and sea lions). This vocal learning ability is believed to have come from an evolutionary modification to the basal ganglia, causing a direct pathway between auditory input and motor output.
What’s amazing is that, at the beginning of the twenty-first century, we can see for the first time the emergence of human culture reflected in the genome. The classic method of examining fossilized skulls continues to reveal new surprises as well. For example, fossil evidence indicates Brodmann area 44 (BA44)—a part of the frontal cortex that is important for auditory motor imitation via mirror neurons there—may well have been in place 2 million years ago, long before
Homo sapiens
(who didn’t emerge until about 200,000 years ago). In other words, the neural mechanisms for language were in place long before they were fully exploited. The FOXP2 gene, closely associated with human language, existed in Neanderthals; a form of it is also found in songbirds. A genetic variant in microcephalin (a part of the genome that encodes for brain development) has been identified. It emerged approximately 37,000 years ago—what we think of as the beginning of culturally modern humans. This coincides, not coincidentally, with the appearance in the archaeological record of artistic artifacts and bone flutes. A second variant of microcephalin arose around 5,800 years ago, corresponding with the first record of written language, the spread of agriculture, and the development of cities. Who knows what we will uncover about this story in the coming decade, but we now know that FOXP2, BA44, and microcephalin variants are part of the evolutionary changes that primed the creation of the musical brain.
The human motor/action imitation system also evolved the ability to imitate with delay—in the absence of the original model. This underlies language, music, religion, painting, and the other arts. Only humans represent, symbolize, and signify things that are not there. (As with recursion, some animals can be trained to do this, indicating that the neural structures are in place, but have not yet been exploited.) With this follows the inevitable question: If I can think about things that are not here—my loved one off on an expedition, that tiger that attacked my friend—are there things not here that I
haven’t
thought about? Are there other worlds, are there entities, that exist outside my experience? This led, as we saw in Chapter 6, to a yearning for spiritual knowledge. It also leads to a yearning to form long-term bonds with loved ones, to gain assurances that they’ll stay with us and come back to us.
Human consciousness, a product of
representation
and thus another feature of the musical brain, appears to be different from animal consciousness as well. As we saw in Chapter 6, animals live in a continuously unfolding present, with no ability (as far as we know) to reflect on the past or plan for the future. Some have argued that everything we humans do is done unconsciously, and that one of the roles of consciousness is to spin a story after the fact about what we did and why we did it. Patients whose two cerebral hemispheres have been surgically separated (for the treatment of intractable epilepsy) often exhibit this kind of post facto rationalization, supporting this notion, and the rationalization typically occurs when the right hemisphere causes the person to do something and the left hemisphere (the hemisphere with language) is left holding the explanatory bag.
Many neuroscientists have been looking for the seat of consciousness in the brain, and I believe that they will never find it—not because consciousness doesn’t exist, but because it is not localizable. Just as we don’t expect to find “gravity” at a particular location in the middle of the earth, we shouldn’t expect to find consciousness at a particular place in the head. I take as an initial assumption the view expressed by my colleague, the McGill University physicist and philosopher Mario Bunge and by other contemporary philosophers, including Paul and Patricia Churchland and Daniel Dennett, that there are no immaterial, vitalistic, or supernatural processes involved in creating the experience we call consciousness; rather, it is a process that arises from the normal functioning of neurons in the human brain.
When biological complexity arises from simpler forms in small steps, we call it evolution. When a wholly unexpected property—such as human consciousness—arises from a complex system, we call it emergence. Ant colonies exhibit an emergent intelligence, finding food, disposing of waste, feeding their queen—yet no ant can be said to “know” in any meaningful sense what it is doing or what the colony is doing. In this respect, ants can be thought of analogously to neurons in the human brain. There is no neuron in your brain that knows your name, and no other neuron that is even bothered by this fact. There is no neuron that knows how old you are, where you were born, what your favorite ice cream is, or whether you are too hot or too cold right now. Neurons just don’t work that way. Hundreds of thousands or millions of neurons need to come together to encapsulate, store, or provide information.
An individual ant, like an individual neuron, is just about as dumb as can be. Connect enough of them together properly, though, and voilà! The system-as-a-whole demonstrates spontaneous intelligence. From the firings and interconnections of billions of neurons, we can look at life and our place in it, we can even think about the nature of our own thoughts. Thoughts emerge from brains, but the process remains mysterious. Emergence has even been invoked as the source of life itself. Consider the so-called primordial soup millions of years ago—a bubbling, boiling compost of carbon, nitrogen, oxygen, hydrogen, proteins, and nucleic acids. The first single-cell organisms arose here, and biologists now believe that
life
arose as an emergent property of the complexity of those first molecular compounds.