importance was missed.
When we carefully examined the speech output of many Wernicke’s aphasics, we found that, in addition to the absence of meaning, the most striking and obvious loss was in recursive embedding. Patients spoke in loosely strung together phrases using conjunctions: “Susan came and hit John and took the bus and Charles fell down,” and so forth. But they could almost never construct recursive sentences such as “John who loved Julie used a spoon.” (Even without setting “who loved Julie” off with commas, we know instantly that John used the spoon, not Julie.) This observation demolishes the long-standing claim that Broca’s area is a syntax box that is autonomous from Wernicke’s area. Recursion may turn out to be a property of Wernicke’s area, and indeed may be a general property common to many brain functions. Furthermore, we mustn’t confuse the issue of functional autonomy and modularity in the modern human brain with the question of evolution: Did one module provide a substrate for the other or even evolve into another, or did they evolve completely independently in response to different selection pressures?
Linguists are mainly interested in the former question—the autonomy of rules intrinsic to the module—whereas the evolutionary question usually elicits a yawn (just as any talk of evolution or brain modules would seem pointless to a number theorist interested in rules intrinsic to the number system). Biologists and developmental psychologists, on the other hand, are interested not only in the rules that govern language but also in the evolution, development, and neural substrates of language, including (but not confined to) syntax. A failure to make this distinction has bedeviled the whole language evolution debate for nearly a century. The key difference, of course, is that language capacity evolved through natural selection over two hundred thousand years, whereas number theory is barely two thousand years old. So for what it is worth, my own (entirely unbiased) view is that on this particular issue the biologists are right. As an analogy, I’ll invoke again my favorite example, the relationship between the chewing and hearing. All mammals have three tiny bones—malleus, stapes, and incus—inside the middle ear. These bones transmit and amplify sounds from the eardrum to the inner ear. Their sudden emergence in vertebrate evolution (mammals have them but their reptilian ancestors don’t) was a complete mystery and often used as ammunition by creationists until comparative anatomists, embryologists, and paleontologists discovered that they actually evolved from the back of the jawbone of the reptile. (Recall that the back of your jaw articulates very close to your ear.) The sequence of steps makes a fascinating story.
The mammalian jaw has a single bone, the mandible, whereas our reptilian ancestors had three. The reason is that reptiles, unlike mammals, frequently consume enormous prey rather than frequent small meals. The jaw is used exclusively for swallowing, not chewing, and due to reptiles’ slow metabolic rate, the unchewed food in the stomach can take weeks to break down and digest. This kind of eating requires a large, flexible, multihinged jaw. But as reptiles evolved into metabolically active mammals, the survival strategy switched to consumption of frequent small meals to maintain a high metabolic rate.
Remember also that reptiles lie low on the ground with their limbs sprawled outward, thereby swinging the neck and head close to the ground while they sniff for prey. The three bones of the jaw lying on the ground allowed reptiles to also transmit sounds made by other animals’ nearby footsteps to the vicinity of the ear. This is called bone conduction, as opposed air conduction which is used by mammals.
As they evolved into mammals, reptiles raised themselves up from the sprawling position to stand higher up off the ground on vertical legs. This allowed two of the three jaw bones to become progressively assimilated into the middle ear, being taken over entirely for hearing airborne sounds and giving up their chewing function altogether. But this change in function was only possible because they were already strategically located—in the right place at the right time—and were already beginning to be used for hearing terrestrially transmitted sound vibrations. This radical shift in function also served the additional purpose of transforming the jaw into a single, rigid nonhinged bone—the mandible—which was much stronger and more useful for chewing.
The analogy with language evolution should be obvious. If I were to ask you whether chewing and hearing are modular and independent of each other, both structurally and functionally, the answer would obviously be yes. And yet we know that the latter evolved from the former, and we can even specify the steps involved. Likewise, there is clear evidence that language functions such as syntax and semantics are modular and autonomous and furthermore are also distinct from thinking, perhaps as distinct as hearing is from chewing. Yet it is entirely possible that one of these functions, such as syntax, evolved from other, earlier functions such as tool use and/or thinking. Unfortunately, since language doesn’t fossilize like jaws or ear bones, we can only construct plausible scenarios. We may have to live with not knowing what the exact sequence of events was. But hopefully I have given you a glimpse of the kind of theory that we need to come up with, and the kinds of experiments we need to do, to account for the emergence of full-fledged language, the most glorious of all our mental attributes.
CHAPTER 7
Beauty and the Brain: The Emergence of Aesthetics
—PABLO PICASSO
AN OLD INDIAN MYTH SAYS THAT BRAHMA CREATED THE UNIVERSE and all the beautiful snow-clad mountains, rivers, flowers, birds, and trees—even humans. Yet soon afterward, he was sitting on a chair, his head in his hands. His consort, Saraswati, asked him, “My lord—you created the whole beautiful Universe, populated with men of great valor and intellect who worship you—why are you so despondent?” Brahma replied, “Yes, all this is true, but the men whom I have created have no appreciation of the beauty of my creations and, without this, all their intellect means nothing.” Whereupon Saraswati reassured Brahma, “I will give mankind a gift called art.” From that moment on people developed an aesthetic sense, started responding to beauty, and saw the divine spark in all things. Saraswati is therefore worshipped throughout India as the goddess of art and music —as humankind’s muse.
This chapter and the next are concerned with a deeply fascinating question: How does the human brain respond to beauty? How are we special in terms of how we respond to and create art? How does Saraswati work her magic? There are probably as many answers to this question as there are artists. At one end of the spectrum is the lofty idea that art is the ultimate antidote to the absurdity of the human predicament—the only “escape from this vale of tears,” as the British surrealist and poet Roland Penrose once said. At the other extreme is the school of Dada, the notion that “anything goes,” which says that what we call art is largely contextual or even entirely in the mind of the beholder. (The most famous example is Marcel Duchamp putting a urinal bowl in a gallery and saying, in effect, “I call it art; therefore it’s art.”) But is Dada really art? Or is it merely art mocking itself? How often have you walked into a gallery of contemporary art and felt like the little boy who knew instantly that the emperor had no clothes?
Art endures in a staggering diversity of styles: Classical Greek art, Tibetan art, African Art, Khmer art, Chola bronzes, Renaissance art, impressionism, expressionism, cubism, fauvism, abstract art—the list is endless. But beneath all this variety, might there some general principles or artistic universals that cut across cultural boundaries? Can we come up with a science of art? Science and art seem fundamentally antithetical. One is a quest for general principles and tidy explanations while the other is a celebration of the individual imagination and spirit, so that the very notion of a science of art seems like an oxymoron. Yet that is my goal for this chapter and the next: to convince you that our knowledge of human vision and of the brain is now sophisticated enough that we can speculate intelligently on the neural basis of art and maybe begin to construct a scientific theory of artistic experience. Saying this does not in any way detract from the originality of the individual artist, for the manner in
