Likewise, a creature that developed a mutation that allowed it to imagine orgasms would fail to pass on its genes and would quickly become extinct. (Our brains evolved long before porn videos,
Now what if our hominin ancestors were worse than us at mental imagery? Imagine they wanted to rehearse a forthcoming bison or lion hunt. Perhaps it was easier to engage in realistic rehearsal if they had actual props, and perhaps these props are what we today call cave art. They may have used these painted scenes in much the way that a child enacts imaginary fights between his toy soldiers, as a form of play to educate his internal imagery. Cave art could also have been used for teaching hunting skills to novices. Over several millennia these skills would become assimilated into culture and acquired religious significance. Art, in short, may be nature’s own virtual reality.
Finally, a fourth, less prosaic reason for art’s timeless appeal may be that it speaks an oneiric, right- hemisphere-based language that is unintelligible—alien, even—to the more literal-minded left hemisphere. Art conveys nuances of meaning and subtleties of mood that can only be dimly apprehended or conveyed through spoken language. The neural codes used by the two hemispheres for representing higher cognitive functions may be utterly different. Perhaps art facilitates communion between these two modes of thinking that would otherwise remain mutually unintelligible and walled off. Perhaps emotions also need a virtual reality rehearsal to increase their range and subtlety for future use, just as we engage in athletics for motor rehearsal and frown over crossword puzzles or ponder over Godel’s theorem for intellectual invigoration. Art, in this view, is the right hemisphere’s aerobics. It’s a pity that it isn’t emphasized more in our schools.
SO FAR, WE have said very little about the creation—as opposed to the perception—of art. Steve Kosslyn and Martha Farah of Harvard have used brain-imaging techniques to show that creatively conjuring up a visual image probably involves the inner (ventromedial cortex) portion of the frontal lobes. This portion of the brain has back- and-forth connections with parts of the temporal lobes concerned with visual memories. A crude template of the desired image is initially evoked through these connections. Back-and-forth interactions between this template and what’s being painted or sculpted lead to progressive embellishments and refinements of the painting, resulting in the multiple, stage-by-stage mini-“Ahas!” we spoke of earlier. When the self-amplifying echoes between these layers of visual processing reach a critical volume, they get delivered as a final, kick-ass “Aha!” to reward centers such as the septal nuclei and the nucleus accumbens. The artist can then relax with her cigarette, cognac, and muse.
Thus the creative production of art and the appreciation of art may be tapping into the same pathways (except for the frontal involvement in the former). We have seen that faces and objects enhanced through peak shifts (caricatures, in other words) hyperactivate cells in the fusiform gyrus. Overall scene layout—as in landscape paintings—probably requires the right inferior parietal lobule, whereas “metaphorical,” or conceptual aspects of art might require both the left and right angular gyri. A more thorough study of artists with damage to different portions of either the right or left hemisphere might be worthwhile—especially bearing in mind our laws of aesthetics.
Clearly we have a long way to go. Meanwhile, it’s fun to speculate. As Charles Darwin said in his
false facts are highly injurious to the progress of science, for they often endure long; but false views, if supported by some evidence, do little harm, for everyone takes a salutary pleasure in proving their falseness; and when this is done, one path toward errors is closed and the road to truth is often at the same time opened.
CHAPTER 9
An Ape with a Soul: How Introspection Evolved
—WILLIAM SHAKESPEARE
JASON MURDOCH WAS AN INPATIENT AT A REHABILITATION CENTER in San Diego. After a serious head injury in a car accident near the Mexican border, he had been in a semiconscious state of vigilant coma (also called akinetic mutism) for nearly three months before my colleague, Dr. Subramaniam Sriram, examined him. Because of damage to the anterior cingulate cortex in the front of his brain, Jason couldn’t walk, talk, or initiate actions. His sleep-wake cycle was normal but he was bedridden. When awake he seemed alert and conscious (if that’s the right word—words lose their resolving power when dealing with such states). He sometimes had slight “ouch” withdrawal in response to pain, but not consistently. He could move his eyes, often swiveling them around to follow people. Yet he couldn’t recognize anyone—not even his parents or siblings. He could not talk or comprehend speech, nor could he interact with people meaningfully.
But if his father, Mr. Murdoch, phoned him from next door, Jason suddenly became alert and talkative, recognizing his dad and engaging him in conversation. That is until Mr. Murdoch went back into the room. Then Jason lapsed back into his semiconscious “zombie” state. Jason’s cluster of symptoms has a name: telephone syndrome. He could be made to flip back and forth between the two states, depending on whether his father was directly in his presence or not.
Think of what this means. It is almost as if there are two Jasons trapped inside one body: the Jason on the phone, who is fully alert and conscious, and the Jason in person, who is a barely conscious zombie. How can this be? The answer has to do with how the accident affected the visual and auditory pathways in Jason’s brain. To a surprising extent, the activity of each pathway—vision and hearing—must be segregated all the way up to the critically important anterior cingulate. This collar of tissue, as we shall see, is where your sense of free will partly originates.
If the anterior cingulate is extensively damaged, the result is the full picture of akinetic mutism; unlike Jason, the patient is in a permanent twilight state, not interacting with anyone under any circumstances. But what if the damage to the anterior cingulate is more subtle—say, the visual pathway to the anterior cingulate is damaged selectively at some stage, but the auditory pathway is fine. The result is telephone syndrome: Jason springs to action (speaking metaphorically!) when chatting on the phone but lapses into akinetic mutism when his father walks into the room. Except when he is on the telephone, Jason is no longer a person.
I am not making this distinction arbitrarily. Although Jason’s visuomotor system can still track and automatically attend to objects in space, he cannot recognize or attribute meaning to what he sees. Except when he is on the phone with his father, Jason lacks the ability to form rich, meaningful metarepresentations, which are essential to not only our uniqueness as a species but also our uniqueness as individuals and our sense of self.
Why is Jason a person when he is on the phone but not otherwise? Very early in evolution the brain developed the ability to create first-order sensory representations of external objects that could elicit only a very limited number of reactions. For example a rat’s brain has only a first-order representation of a cat—specifically, as a furry, moving thing to avoid reflexively. But as the human brain evolved further, there emerged a second brain—a set of nerve connections, to be exact—that was in a sense parasitic on the old one. This second brain creates metarepresentations (representations of representations—a higher order of abstraction) by processing the
