The Mind and the Brain (41 page)

In contrast to classical physics, with its exclusive focus on material causation, quantum physics offers a mechanism that validates the intuitive sense that our conscious thoughts have the power to affect our actions. Quantum theory, in the von Neumann-Wigner formulation as developed by Henry Stapp, offers a mathematically rigorous alternative to the impotence of conscious states: it allows conscious experience to act back on the physical brain by influencing its activities. It describes a way in which our conscious thoughts and volitions enter into the causal structure of nature and focus our thoughts, choose from among competing possible courses of action, and even override the mechanical aspects of cerebral processes. The quantum laws allow mental effort to influence the course of cerebral processes in just the way our subjective feeling tells us it does. How? By keeping in focus a stream of consciousness that would otherwise diffuse like mist at daybreak. Quantum theory demonstrates how mental effort can have, through the process of willfully focusing attention, dynamical consequences that cannot be deduced or predicted from, and that are not the automatic results of, cerebral mechanisms acting alone. In a world described by quantum physics, an insistence on causal closure of the physical
world amounts to a quasi-religious faith in the absolute powers of matter, a belief that is no more than a commitment to brute, and outmoded, materialism.

An obvious question is how far one can extend the reach of the hypothesized mental force. As the Decade of the Brain ended, neuroscientists had mapped out the neural circuits that underlie myriad states and behaviors, from depression to aggression to suicidal impulses. Does the existence of mental force imply that with enough attention and volition the violent teen can will himself the brain circuits that make a civilized adult of him? That the suicidal widow can will herself the neural circuits correlated with a love of life, or at least spiritual acceptance? That the schizophrenic can will his voices to be silent, and his visions to disappear? The power of cognitive-behavioral therapy to alter brain circuits in people with either depression or OCD implies that similar therapy, drawing on mental force, should be able to change other circuitry that underlies an aspect of personality, behavior, even thought. And that, of course, encompasses approximately everything, from the mundane to the profound: addiction or temperance, a bad temper or a forgiving nature, impatience or patience, love of learning or antipathy to it, generosity or niggardliness, prejudice or tolerance.

There is a danger to this way of thinking: it treads close to the position that anyone with a mental illness remains sick because of a failure of will, anyone with an undesirable personality trait retains it because she has failed to exert sufficient mental effort. Even those of us who distrust the “My genes (or my neurochemicals) made me do it” school of human behavior back away from the implication that will alone can bring into being the neural circuitry capable of supporting any temperament or behavioral tendency—indeed, any state of mental health. But to frame the issue in this all-or-nothing way is to create a simplistic, and false, choice. The distinction between active and passive mental events offers us some flexibility as we search for where free will and mental force might exhaust their powers. That the passive side of the picture is largely deter
mined, no one can deny. That the intensity of that passive conscious content can at times be overwhelming, no one with an ounce of empathy can fail to realize. Sometimes the power of those passive, unbidden, and unwanted brain processes—the voices the schizophrenic hears, the despair a depressive feels—is simply too great for mental force to overcome. And although directed mental force allows will to change the brain in both the stroke patients Edward Taub has treated and my own OCD patients, of course it is not will alone. It is knowledge, training, support from the community and loved ones, and appropriate medical input.

Twenty-five hundred years ago, a culture very distant from our own in both time and place produced an astonishing prescient insight. In the Pali texts, Gotama says, “It is volition, monks, that I declare to be Karma (Action). Having willed, one perfoms an action by body, speech or mind.” By these words the Buddha meant that it is the state of one’s will that determines the nature of one’s actions (karma), and so profoundly influences one’s future states of consciousness. This is the Law of Karma. As the Buddhist scholar Ledi Sayadaw explains, “Volition becomes the chief and supreme leader in the sense that it informs all the rest. Volition, as such, brings other psychical activities to tend in one direction.” In addition, Gotama vividly described how the quality of attention that one places on a mental or physical object determines the type of conscious state that arises in response to that object. As the next few months of my collaboration with Henry Stapp were to show, Gotama wasn’t a bad neuroscientist—or physicist either, for that matter. By the time Stapp wrote his paper for “Volitional Brain,” we were well on the way toward identifying a quantum-based mechanism by which the mental effort that generates “willful focus of attention” would bring about brain changes like those detailed in the OCD brain imaging work. Attention was key.

The implication of the preceding chapters—particularly the power of mental effort and mindfulness to alter neuronal connections—is that will is neither myth nor metaphor. It is, or at least
exerts, a real physical force. The research on OCD makes clear that will involves different levels of consciousness, with high-order mental functions potentially presiding over lower-level ones. As 1999 passed, with fireworks and laser shows, into 2000, Stapp and I worked to connect the seemingly disparate threads of a nascent theory: William James’s observations about will and attention, my work showing the power of mental effort to change the brain patterns of OCD patients, and quantum physics. James foreshadowed the mechanism by which, according to Stapp, volition acts through quantum processes: “At various points,” James wrote, “ambiguous possibilities shall be left open, either of which, at a given instant, may become actual. [One] branch of these bifurcations become[s] real.”

On Christmas Eve day 1999, I flew up to San Francisco, taking advantage of a seventy-nine-dollar round-trip fare so that I could touch base with Henry Stapp. Henry picked me up at the airport, and after lunch at a trattoria in North Beach we drove across the bridge to Berkeley. I had recently been rereading William James’s work on attention, I told Henry, and realized how uncannily the perspective of this nineteenth-century psychologist foreshadowed the work Henry was doing. I hadn’t taken my copy of James’s
Psychology: A Briefer Course
with me, so Henry and I set out to find one.

After parking near Telegraph Avenue, we walked past street people slumped against doorways and sprawled across sidewalks, the gaiety of stores’ Christmas decorations forming an incongruous backdrop. We ducked into Cody’s bookstore and split up, looking for James everywhere from self-help to religion. No luck. But at Moe’s used bookstore down the block, we hit paydirt. There in the psychology section, amid what seemed like oceans of Jung, was a single slim volume of James. I opened it to this passage:

As we stood at the counter paying for our find, I could tell by the change in Henry’s usually impassive demeanor that I had piqued his interest. “See—I told you it was uncanny how relevant James was to the physics of attention!” I said. Even the guy behind the cash register seemed interested.

Walking down the street to Henry’s car, I continued reading aloud. (This was Berkeley on Christmas Eve: no one looked twice at us.) But there was more, I told Henry. Riffling through the book, I opened it to a passage several chapters later: “Volitional effort is effort of attention.” And this: “The function of the effort is…to keep affirming and adopting a thought which, if left to itself, would slip away.” And, “Effort of attention is thus the essential phenomenon of will.” And finally, “To sustain a representation, to think, is,
in short, the only moral act.” Here we got to the nub of it, the conviction that the act of focusing attention so that one thought, one possible action, prevails over all the other possible ones competing for dominance in consciousness—this is the true moral act, the point where volition enters into what James had just called “the cerebral conditions” and, moreover, “contribute[s] coequally” to them in determining which of those competing thoughts and actions will be chosen. It is this power of attention—to select one possibility over all others—that invests us with an efficacious will.

“It’s uncanny,” I repeated. “It’s unbelievable,” Henry said. A man of the nineteenth century had described in detail the connection between the quantum-based theory of attention and volition that we described in our “Volitional Brain” papers. The causal efficacy of will, James had intuited more than one hundred years ago, is a higher-level manifestation of the causal efficacy of attention. To focus attention on one idea, on one possible course of action among the many bubbling up inchoate in our consciousness, is precisely what we mean by an act of volition, James was saying; volition acts through attention, which magnifies, stabilizes, clarifies, and otherwise makes predominant one thought out of many. The essential achievement of the will is to attend to one object and hold it clear and strong before the mind, letting all others—its rivals for attention and subsequent action—fade away like starlight swamped by the radiance of the Sun. That was just the idea that had emerged from the quantum approach. I handed the book to Henry and said, “Merry Christmas, and happy New Millennium.”

Once settled in Henry’s car, we drove back across the Bay Bridge, talking animatedly about how James had come to a scientific understanding of the origin and efficacy of volition that was exactly in line with what quantum theory was telling us a century later. We were just picking up where James left off, I felt; it was as if we’d encountered a time warp that bypassed the entire twentieth century and took us directly from the late nineteenth century to the year 2000.

Given James’s strong philosophical bent, it’s hardly surprising these twin concepts, attention and will, were of such tremendous importance to him. He was well aware, especially given his goal of placing psychology squarely within natural science, that thickets of controversy awaited anyone willing to tackle the question of free will. But on the key point of the causal efficacy of attention, and its relation to will, James held fast to his belief—one he suspected could not be proved conclusively on scientific grounds, but to which he clung tenaciously on ethical grounds—that the effort to focus attention is an active, primary, and causal force, and not solely the result of properties of a stimulus that acts on a passive brain. Between his 1,300-plus-page
Principles
and the 443-page
Briefer Course
published fifteen months later, he did not budge from (indeed, he elaborated on) the statement that effortful attention “would deepen and prolong the stay in consciousness of innumerable ideas which else would fade more quickly away.” If we can but understand the effort of attention, James believed, we will have gone a very long way toward understanding the nature of will.

What particularly struck me was James’s recognition of the high stakes involved. The question of whether attention (and therefore will) follows deterministically upon the predictable response of brain cells to stimuli, or whether the amount of attention can be (at least sometimes) freely chosen and causally efficacious, “is in fact the pivotal question of metaphysics, the very hinge on which our picture of the world shall swing from materialism, fatalism, monism, towards spiritualism, freedom, pluralism,—or else the other way.” James was scrupulously fair in giving equal time to the view that attention is a fully determined result of brain function rather than a causally efficacious force. As he notes, it is entirely plausible that attention may be “fatally predetermined” by purely material laws. In this view, the amount of attention we pay a stimulus, be it one from the world outside or an internally generated thought or image, is determined solely by the properties of that stimulus and their interaction with our brain’s circuits. If the words
you hear or the images you see are associated with a poignant memory, for instance, then they trigger—automatically and without any active effort by you—more attention than stimuli that lack such associations. In this case, “attention only fixes and retains what the ordinary laws of association bring ‘before the footlights’ of consciousness,” as James put it. That is, the stimuli themselves provoke neural mechanisms that cause them to be attended to and fixed on. This is the attention-as-effect school of thinking.

But James did not think that attention was always and only a fully determined effect of the stimuli that are its object. On the flight back to Los Angeles, I went over in my own mind what we knew about attention, and why it mattered.

We go through our lives “seeing” countless objects that we do not pay attention to. Without attention, the image (or the sound, or the feel—attention plays a role in every sense) does not register in the mind and may not be stored even briefly in memory. I can guarantee that if you were to scan every square centimeter of a crowd scene in a photograph, visual information about every person depicted would reach your visual cortex. But if I asked you, after you had scanned the photo of the crowd, where the man in the fedora and vest was, you would doubtless be flummoxed. Our minds have a limited ability to process information about multiple objects at any given time. “Because of limited processing resources,” as the neuroscientists Sabine Kastner and Leslie Ungerleider of NIH wrote in a 2000 review of attention, “multiple objects present at the same time in the visual field compete for neural representation…. Two stimuli present at the same time within a neuron’s receptive field are not processed independently. [R]ather,…they interact with each other in a mutually suppressive way.” They compete for neural representation. The key question for attention is, What determines the winner?

Let’s say I asked you, before you looked at the picture, to find the man in fedora and vest. With your mind thus primed, you would probably find him in seconds. You would have selected the
relevant stimulus and filtered out the extraneous ones. How? According to our best understanding, the images of scores of people (to continue with our example of the crowd photo) sped from your retina and into your visual cortex, in parallel. But then competition set in. The winner was determined by the strength of the stimulus (perhaps the man in the fedora is brighter than the other images), by its novelty (we tend to pick out, say, the tuxedoed monkey at a black-tie dinner before we notice the humans), by its strong associations (if you scan a crowd scene for someone you know, you can generally pick her out before a stranger), or, most interestingly, by the demand of the task—in this case, looking for “the man in fedora and vest.” Selectively focusing attention on target images significantly enhances neuronal responses to them.

This is especially true when nearby stimuli, if not for the power of attention, would distract us. In general, when two images are presented simultaneously, each suppresses the neuronal activity that the other triggers. But selective focusing of attention can override this effect and thereby filter out distractions. How do we know? When physiologists record electrical activity in the brains of monkeys doing tasks that require selective attention, they find that the firing of neurons activated by a target image becomes significantly enhanced when the monkeys selectively focus attention on it, effectively eliminating the suppressive influence of nearby images. Human brains act the same way, according to functional magnetic resonance imaging (fMRI) : neurons that respond to a target (the image attracting your attention) fire more strongly than neurons that respond to a distraction. The act of paying attention, then, physically counteracts the suppressive influences of nearby distractions. Robert Desimone of the National Institute of Mental Health, one of the country’s leading researchers into the physiology of attention, explains it this way: “Attention seems to work by biasing the brain circuit for the important stimuli. When you attend to a stimulus, the suppression that distracters otherwise cause is reduced.”

In other words, selective attention can strengthen or weaken neural processing in the visual cortex. This seems to happen in at least two ways. In the first, the neural response to the object of attention becomes stronger. In one fascinating series of experiments, monkeys were trained to look for the color of an object that flashed on a screen. When they did, neurons that respond to color became more active. Similarly, when the monkeys were trained to keep an eagle eye on the direction an object was moving, or on its orientation, neurons that perform those tasks became more active. Attention to shape and color pumps up the volume of neuronal activity in the region of the visual cortex that processes information about shape and color; attention to speed turns up the activity of neurons in the region that processes information about speed. In people, paying attention to faces turns up activity in the region whose job it is to scan and analyze faces.

If this seems somewhat self-evident, it’s worth another look: the visual information reaching the brain hasn’t changed. What has changed—what is under the observer’s control—is the brain’s response to that information. Just as visual information about the color of this book’s cover reached your brain as you opened it, so every aspect of the objects on the screen (their shape, color, movements, etc.) reached the monkey’s brain. The aspect of the image that monkey pays attention to determines the way its brain responds. Hard-wired mechanisms in different brain areas get activated, or not, depending on what the monkey is interested in observing. An activity usually deemed to be a property of the mind—paying attention—determines the activity of the brain.

Attention can do more than enhance the responses of selected neurons. It can also turn down the volume in competing regions. Ordinarily—that is, in the absence of attention—distractions suppress the processing of a target stimulus (which is why it’s tough to concentrate on a difficult bit of prose when people are screaming on the other side of a thin wall). It’s all well and good for a bunch of
neurons to take in sounds at a boisterous party, but you can’t make out a damn thing until you pay attention. Paying attention to one conversation can suppress the distracting ones. Neurons that used to vibrate with the noise of those other conversations are literally damped down and no longer suppress the response of neurons trying to hear the conversation you’re interested in. Anyone who has ever had the bad luck to search for a dropped contact lens has also had the experience of paying attention to one object (the lens) and thus suppressing neuronal responses to other objects (bits of lint in a rug). If you are searching for a contact lens on a Persian rug, you can thank this effect for hushing the neurons that respond to those flowers and colors, and turning up the responses of neurons that respond to the glimmer of light reflecting off little clear disks. Specifically, it is the activity of neurons deep in the brain’s visual pathway, rather than in the primary visual cortex, that is damped down or turned up by attention.