A Music is one of the human species's relatively few universal abilities. Without formal training, any individual, from Stone Age tribesmen to suburban teenagers, has the ability to recognize music and, in some fashion, to make it. Why this should be so is a mystery. After all, music isn't necessary for getting through the day, and if it aids in reproduction, it does so only in highly indirect ways. Language, by contrast, is also everywhere but for reasons that are more obvious. With language, you and the members of your tribe can organize a migration across Africa, build reed boats and cross the seas, and communicate at night even when you can't see each other. In all its technological extravagance, modern culture springs directly from the human talent for manipulating symbols and syntax. Scientists have always been intrigued by the connection between music and language. Yet over the years, words and melody have acquired a vastly different status in the lab and the seminar room. While language has long been considered essential to unlocking the mechanisms of human intelligence, music is generally treated as an evolutionary frippery, mere auditory cheesecake, as the Harvard cognitive scientist Steven Pinker puts it.
28B But thanks to a decade-long wave of neuroscience research, that tune is changing. A flurry of recent publications suggests that language and music may equally be able to tell us who we are and where we're from – not just emotionally, but biologically. And in an article in the August 6 issue of the journal Neuroscience, David Schwartz, Catherine Howe, and Dale Purves of Duke University argued that the sounds of music and the sounds of language are intricately connected. To grasp the originality of this idea, it's necessary to realize two things about how music has traditionally been understood. First, musicologists have emphasized that while each culture stamps a special identity onto its music, music itself has some universal qualities. For example, in virtually all cultures, the sound is divided into some or all of the 12 intervals that make up the chromatic scale – the scale represented by the keys on a piano. For centuries, observers have attributed this preference for certain combinations of tones to the mathematical properties of sound itself. Some 2,500 years ago, Pythagoras was the first to note a direct relationship between the harmoniousness of a tone combination and the physical dimensions of the object that produced it. For example, a plucked string will always play an octave lower than a similar string half its size and a fifth over a similar string two-thirds its length. This link between simple ratios and harmony has influenced music theory ever since.
29C This music-is-math idea is often accompanied by the notion that music, formally speaking, exists apart from the world in which it was created. Writing recently in The New York Review of Books, pianist and critic Charles Rosen discussed the long-standing notion that while painting and sculpture reproduced at least some aspects of the natural world and writing describes thoughts and feelings we are all familiar with, music is entirely abstracted from the world in which we live. Neither idea is right according to David Schwartz and his colleagues. Human musical preferences are fundamentally shaped not by elegant algorithms or ratios but by the messy sounds of real life and of speech in particular - which, in turn, is shaped by our evolutionary heritage. 'The explanation of music, like the explanation of any product of the mind, must be rooted in biology, not in numbers pulse,' says Schwartz.
Schwartz, Howe, and Purves analyzed a vast selection of speech sounds from a variety of languages, to reveal the underlying patterns common to all utterances. In order to focus only on the raw sound, they discarded all theories about speech and meaning and sliced sentences into random bites. Using a database of over 100,000 brief segments of speech, they noted which frequency had the greatest emphasis on each sound. They discovered that the resulting set of frequencies corresponded closely to the chromatic scale. In short, the building blocks of music are to be found in speech.
Far from being abstract, music presents a strange analog to the patterns created by the sounds of speech. 'Music, like the visual arts, is rooted in our experience of the natural world,' says Schwartz. 'It emulates our sound environment in the way that visual arts emulate the visual environment.' In music we hear the echo of our basic sound-making instrument - the vocal tract. The explanation for human music is simpler still than Pythagoras's mathematical equations: We like the sounds that are specific, we like sounds that remind us of us, familiar to us. This brings up some chicken-or-egg evolutionary questions. It may be that music imitates speech directly, the researchers say, in which case it would seem that language evolved first. It's also conceivable that music came first, and language is, in effect, an imitation of song - that in everyday speech, we hit the musical notes we especially like. Alternately, it may be that music imitates the general products of the human sound-making system, which just happens to be mostly speech. 'We can't know this,' says Schwartz. 'What we do know is that they both come from the same system, and it is this that shapes our preferences.'
30D Schwartz's study also casts light on the long-running question of whether animals understand and appreciate music. Despite the apparent abundance of 'music' in the natural world - birdsong, whale song, wolf howls, synchronized chimpanzees - previous studies have found that laboratory animals don't show a great affinity for the human variety of music making. Marc Hauser and Josh McDermott of Harvard argued in the July issue of Nature Neuroscience that animals don't create or perceive music the way we do. The fact that laboratory monkeys can show recognition of human tunes is evidence, they say, of shared general features of the auditory system, not any specific chimpanzee musical ability. As for birds, those most musical beasts, they generally recognize their own tunes and narrow repertoire but don't generate novel melodies like we do. There are no avian Mozarts.
But what's been played to the animals, Schwartz notes, is human music. If animals evolve preferences for sound as we do - based upon the soundscape in which they live - then their 'music' would be fundamentally different from ours. In the same way that our scales derive from human utterances, a cat's idea of a good tune would derive from yowls and meows. To demonstrate that animals don't appreciate sounds the way we do, we'd need evidence that they don't respond to 'music' constructed from their own sound environment.
31E No matter how the connection between language and music is parsed, what is apparent is that our sense of music, even our love for it, is as deeply rooted in our biology and in our brains as language is. This is most obvious with babies, says Sandra Trehub at the University of Toronto, who also published a paper in the Nature Neuroscience special issue. For babies, music and speech are on a continuum. Mothers use musical speech to 'regulate infant emotional states,' Trehub says. Regardless of what language they speak, the voice all mothers use with babies is the same: something between speech and song. This kind of communication puts the baby in a trance-like state, which is probably not very surprising. The upshot, says Trehub, is we probably don't realize just how much of a necessity music is.