The Ravenous Brain: How the New Science of Consciousness Explains Our Insatiable Search for Meaning

by Bor, Daniel

  THE FRUITS OF CHUNKING AND AWKWARD SELF-CONSCIOUSNESS

  The third and final aspect of chunking in relation to consciousness is what we do with those chunks when we’ve firmly acquired them. In this case, it’s generally better if we’re not aware of them—at least not anything other than the absolute top-level chunk we’re currently dealing with.

  The main purpose of awareness is either to manage tasks too new or complex for our simpler unconscious mind or to innovate, to find patterns in our working memory, so that we can optimize and automate biologically relevant goals. But once those tasks have been heavily learned, if they take up consciousness again, then that is far from ideal. First, because we are simultaneously analyzing the details of the task, we are likely to perform it less efficiently than when it was an automatic habit. Then there is the issue of energy use: Consciousness requires a large and active network of cortical regions, which in turn need considerably more energy than unconscious, automatic habits. So it is wasteful to use consciousness for anything other than its official purpose, to discover potentially significant opportunities to improve our mental programming.

  Some chunks are too complex for our unconscious minds to handle and instead serve to guide our consciousness toward a specific goal. For instance, if I want to make a relatively nontrivial change to my PC, such as modifying the monitor resolution, I know exactly what sequence of mouse clicks to make to achieve this, and each one has to be consciously controlled. But the vast majority of these well-learned packets of information can whirr away quite happily while conscious engagement is entirely elsewhere—for instance, me walking for many minutes, oblivious to my surroundings, or driving while daydreaming.

  It’s very much as if we had two modes: a slow, deliberative, highly conscious system, there to detect novel or ever more complex forms of patterned information, to find its structural essence, which we use to build chunks; and a fast, automatic, barely conscious system, which takes advantage of the well-honed chunks that consciousness has previously formed.

  This dual mode is highly reminiscent of the balance in nature between well-established genetic traits and chaotic innovation. Recall that if an organism is coping well, then mutation rates are lower. During these times of stability, creatures such as the nematode worm will rely on the more faithful replication mode of cloning. They are in effect banking on their previously effective DNA-based beliefs about the world, and resisting attempts to change. But if there are severe stresses to life, and innovation is required to ensure survival of offspring, then random mutation rates or sexual selection will become more likely, as if the species were attempting to breed a novel successful genetic trait in the next generation. In other words, a more dynamic, daring approach is needed in order to find a tangential solution to the current problem.

  The similarities between these genetic processes and consciousness are more than skin deep. They relate to the general question of where you sit on an information-processing continuum between stability and chaos. It’s a good policy to err on the side of stability if things are going well, and bank on those previous insights that are currently working, but to verge toward the chaotic, innovative side when life is dangerously threatened.

  The interplay between conscious chunk formation and unconscious automatic processes is an attempt at simultaneously exploiting both sides of the information-processing coin. One way of viewing consciousness is as an innovation machine, there to dabble with the chaotic side when at an impasse and new ideas are required to improve matters. But, unlike the genetic tricks, consciousness carries out these semi-chaotic probings in a relatively safe and highly directed way, only accepting those new insights that will clearly benefit the animal, either in terms of adding to its world picture or enhancing its behavior. Then, once these innovative chunks have been discovered, they are incrementally added to the stable portion of cognition, which largely resides in the unconscious.

  This view highlights the evolutionary advantage of awareness. Engaging consciousness admittedly eats up resources, as the most energy-hungry parts of the brain are engaged. However, the energy savings that ensue far outweigh the initial costs, since existing tasks become efficiently streamlined and new, intelligent techniques are discovered that allow us to avoid complex threats and obtain challenging rewards.

  While this division of labor is fantastically effective on the whole, we can really screw things up by mixing these two modes. This happens when we deliberately try to be conscious of well-worn chunks of skill or memory. It’s important that we can open up our consciousness like this on occasion, at least partially. This way we notice faults in deep habits and can improve, even if we are likely to interfere with performance while the reassessment is being made. But many times, this mixture just produces, at best, semi-defective results. It is a mode we colloquially label as being “self-conscious.”

  For instance, if you start attending to every little movement of your tennis forehand stroke, the fluidity falls apart. You are overloading your working memory far beyond its capacity and it becomes overwhelmed. To take an exaggerated view, you might place in working memory just the first, eighth, twelfth, and fifteenth component of the muscle sequences, and this will result in a very awkward motion, hardly resembling the fluid forehand you demonstrated without much awareness a minute ago.

  You have also reentered a state in which you are questioning and analyzing every aspect of your movements, a state that is ravenous for new information, for novel, efficient patterns of thought and behavior. You are temporarily rejecting the information you’ve built up about your structured movements, and instead are searching for patterns anew. You would be far more aware of any movements now and might be able to reconstruct or tweak your forehand technique, but at the expense of having the previous elegant chunk of forehand motor memory at your ready disposal.

  Ample evidence from the lab supports this dual-mode view, where consciousness is initially necessary for complex learning, but then largely gets in the way of automatic processing once the lesson has been firmly acquired. For instance, in a series of elegant experiments, Sian Beilock and colleagues tested how golf-putting performance can be manipulated according to where we point our attention. If expert golfers are told to focus on the swing of their club, then the ball ends up further from the hole compared with when their attention is distracted by another task, namely, listening for certain target sounds amid a stream of beeps. This set of results is the exact opposite of what happens with novices, who are far more accurate in their golf swings when focusing on the movement of the club, compared with trying to listen for these target beeps. Very similar results have been found in soccer, baseball, and even touch typing.

  But leaving these uncommon glitches of our conscious system aside, the fruits of chunking do allow us to excel at almost every field, as long as we put in the time. Many hours of practice, directed in the right way, enables our working memory to spot increasingly subtle, sophisticated patterns relevant to the task.

  Our ability to consciously apply our chunking skills, both by detecting crucial regularities in a sudden burst of insight and by more patiently, steadily building up layers of structured knowledge over months or years, is essentially responsible for every human advance and every intellectual achievement in our history.

  Our collective curiosity, working intimately with our prodigious talent for noticing patterns in our world, has yielded many incredible scientific insights and technological marvels. And, I would argue, our most cherished artists, writers, and musicians couldn’t have produced their gifts to culture without their skills for seeing the hidden structures around them. Geniuses in these fields should perhaps be defined not only by raw ability, but also by their years of painstaking, focused, conscious attention, which allows them to detect and construct deeper chunks than the rest of us.

  5

  The Brain’s Experience of a Rose

  Neuroscience of Awareness

  QUIT WHILE YOU’RE AHEAD?

>   Recently, I was fortunate to attend a two-day symposium on consciousness and cognition organized by the Royal Society, the UK’s main scientific society. A select group of leading lights from neuroscience around the world descended on a small village in the middle of England. They came to give various talks on the progress science is making in unlocking how the brain creates consciousness. Their audience included members of the society as well as people working closely in the field, like me. The location was Chicheley Hall, a beautiful English mansion owned by the Royal Society that it uses when hosting mini-conferences like this one. With exquisite gardens around us, decadent food, and plush accommodation, the atmosphere was surprisingly informal.

  One of the speakers, Michael Gazzaniga, is one of the old grandees of cognitive neuroscience. He’s been highly influential for many decades in the field of neuroscience, not only in terms of research and teaching but also in communicating its discoveries to a wider audience. Now in his early seventies, he’s a tall, charismatic, friendly man with an easy, welcoming laugh. He began his own talk by relating what had happened to him a few days earlier on entering the country. Arriving at London’s Heathrow Airport, he made his way to passport control. The passport officer asked him the standard question: whether he was there on business or pleasure . . . business was the answer, for a few days, to give a talk. The officer asked him what business he was in. He explained that he was a brain scientist, which caused the officer to raise an eyebrow. This officer, increasingly intrigued, said, “You mean like the right brain does spatial stuff and the left brain does language?” Feeling both lucky and rather proud, Gazzaniga replied that, actually, he’d had a part to play in establishing this result many years ago. The officer, impressed, asked Gazzaniga what he was going to talk about this time. Gazzaniga replied, “Perspectives on consciousness and the brain.” The passport officer gave him a sideways look and a frown before suggesting, “Have you ever thought of quitting while you’re ahead?”

  It isn’t just the public that cocks a suspicious gaze toward the neuroscience of consciousness. Many neuroscientists feel the same way themselves, even now. And yet, as I will relate in this chapter, much exciting progress has been made in the field in the past two decades, and researchers are beginning to converge on a view of what brain areas are involved in consciousness, how these regions interact to generate our experiences, and the signature neural features that mechanistically explain awareness.

  MY CONSCIOUS MIND IS MY CONSCIOUS BRAIN

  In Chapter 1 I recounted how my friend Martin Monti had employed the fMRI scanner, with me inside it, as possibly one of the most expensive, most cumbersome chat tools on earth. And yet, it demonstrated in a relatively elegant way that my conscious thoughts were physical thoughts, that my brain was the specific location where my consciousness resided. Any philosophical position that opposes this stance is balancing on quicksand.

  Not only do we manipulate our consciousness every day by interfering with brain function, by way of the drugs we consume, such as caffeine or alcohol, but countless medical examples make the link even more obvious. For instance, many different forms of brain damage cause profound and lasting changes to consciousness.

  If we assume that consciousness is simply a physical process generated by brain activity, then this makes the mystery of awareness all the more vivid and exciting; it gives us a provisional scaffold to examine so that we can try to find answers. Linking consciousness with the brain admittedly raises a new set of questions, but now they are pointed and open to scientific investigation: Does the whole human brain generate consciousness—or a few specific regions? If only a subset, what differentiates these from the others? Is consciousness related to some particular way that neurons can talk to each other, or is this irrelevant? Does the number of neurons matter, or can consciousness reside in just a handful of nerve cells? Are there different kinds of consciousness for different brain regions, each processing distinct functions, such as our perception of faces and language, or is there only one form of consciousness? And does consciousness have to be tied to brains, or can it be supported by other suitable physical structures—for instance, a silicon-based computer? This chapter is devoted to answering these questions. But it will also continue the work of the previous chapter by making broader claims about the purpose, composition, and mechanism of consciousness.

  Figure 1. Harlow’s illustration of the path that the tamping iron took through Phineas Gage’s skull and brain.

  Figure 2. Various examples of complexity arising from simpler underlying structures, rules, or behaviors. Top left: the collapse of the Dow Jones Industrial Average following the 2007–2008 credit crunch. Top right: ants working together to form a bridge across a gap that would be too great for any individual ant to traverse on its own. Bottom left: an example of a spiral galaxy. Bottom right: a Julia set fractal.

  Figure 3. Schematic of the human brain, with the most primitive (“reptilian”) brain in the center, the limbic (“early mammalian”) system surrounding this, and the (“late mammalian”) neocortex making up the outer shell.

  Figure 4. The four lobes of the human brain.

  Figure 5. An example of change blindness. The two figures are repeatedly swapped, in between a blank grey screen, until the volunteer spots the blatant but unexpected change.

  Figure 6. Examples of stimuli that induce repeated switches in visual perception. In the top example, involving binocular rivalry, a single mixed picture presents a face to one eye and a house to the other, because of red/green filtered glasses. The experience flips between only a face and only a house randomly over time. In the bottom two examples, we experience either only a candlestick or only two profile faces (left), and either only an old woman or only a young woman (right), and our experience again flips back and forth randomly over time.

  Figure 7. (a) Illustration of the three types of cup assembly. Strategy 1 merely involves putting one cup inside another, and not completing the puzzle. Strategy 2 involves putting the cups inside each other one at a time, and never moving a cup with another inside it. Although the puzzle can be completed in this way, it’s different from the demonstration that the experimenter showed the participant. Finally, there is strategy 3, which involves some level of hierarchy, as both the smaller and middle cups are moved simultaneously to fit into the larger cup. (b) Graphs to show dominant strategy used for infants and animals—strategy 1 in blue, 2 in magenta, and 3 in yellow.

  Figure 8. In the fMRI scanner, normal volunteers see a 4 by 4 grid of red squares. Four of them blink blue in a sequence, which the volunteers have to remember for a few seconds. The left side is an example of a structured sequence, and the right side is an unstructured example.

  Figure 9. A CT scan comparison of a normal brain, on the left, and Terri Schiavo’s brain, on the right.

  The study of how the brain creates consciousness involves two surprisingly disconnected wings. The first side has explicitly sought to discover the brain areas and neural mechanisms responsible for consciousness. But in parallel to this strand of research, a largely separate group of scientists has been revealing equally insightful discoveries about the neural recipes for our experiences, despite the fact that they rarely even mention consciousness. Instead, their topics of investigation include the neuroscience of working memory, attention, and chunking.

  In this chapter, I will recount the direct, official evidence for how the brain generates our sense of awareness. But then I will show how the study of the neural underpinnings of attention, working memory, chunking, and related topics map closely onto the “official” set of consciousness data, providing further evidence for the importance of these processes to consciousness. In the final section of the chapter I will describe current neural theories of consciousness to provide deeper insights into its nature, especially when strengthened by a synthesis of the two experimental stories.

  OPENING THE FLOODGATES

  Probably the simplest question to ask of the neuroscience of conscious
ness, and therefore a natural first point of attack, is whether the whole brain contributes to consciousness, or merely a few of its key areas. There is an unfortunate abundance of data on this question in the form of patients with damage to different brain regions. En masse, this population of patients has localized damage to every brain region there is. This allows us to know, for instance, that the cerebellum, part of the ancient reptilian section of the human brain, has little to do with awareness. Patients missing a cerebellum show no clear impairments of consciousness. For instance, one woman was born with almost no cerebellum in either hemisphere, but she was able to lead a relatively normal life, holding down a job at an electronics factory.