The Future of the Mind Page 6

  WHO IS IN CHARGE?

  One person who has spent considerable time and done much research to understand the problem of the subconscious mind is Dr. David Eagleman, a neuroscientist at the Baylor College of Medicine. When I interviewed him, I asked him, If most of our mental processes are subconscious, then why are we ignorant of this important fact? He gave an example of a young king who inherits the throne and takes credit for everything in the kingdom, but hasn’t the slightest clue about the thousands of staff, soldiers, and peasants necessary to maintain the throne.

  Our choice of politicians, marriage partners, friends, and future occupations are all influenced by things that we are not conscious of. (For example, it is an odd result, he says, that “people named Denise or Dennis are disproportionately likely to become dentists, while people named Laura or Lawrence are more likely to become lawyers, and people with names like George or Georgina to become geologists.”) This also means that what we consider to be “reality” is only an approximation that the brain makes to fill in the gaps. Each of us sees reality in a slightly different way. For example, he pointed out, “at least 15 percent of human females possess a genetic mutation that gives them an extra (fourth) type of color photoreceptor—and this allows them to discriminate between colors that look identical to the majority of us with a mere three types of color photoreceptors.”

  Clearly, the more we understand the mechanics of thought, the more questions arise. Precisely what happens in the command center of the mind when confronted with a rebellious shadow command center? What do we mean by “consciousness” anyway, if it can be split in half? And what is the relationship between consciousness and “self” and “self-awareness”?

  If we can answer these difficult questions, then perhaps it will pave the way for understanding nonhuman consciousness, the consciousness of robots and aliens from outer space, for example, which may be entirely different from ours.

  So let us now propose a clear answer to this deceptively complex question: What is consciousness?

  The mind of man is capable of anything … because everything is in it, all the past as well as all the future.

  —JOSEPH CONRAD

  Consciousness can reduce even the most fastidious thinker to blabbering incoherence.

  —COLIN MCGINN

  2 CONSCIOUSNESS—A PHYSICIST’S VIEWPOINT

  The idea of consciousness has intrigued philosophers for centuries, but it has resisted a simple definition, even to this day. The philosopher David Chalmers has cataloged more than twenty thousand papers written on the subject; nowhere in science have so many devoted so much to create so little consensus. The seventeenth-century thinker Gottfried Leibniz once wrote, “If you could blow the brain up to the size of a mill and walk about inside, you would not find consciousness.”

  Some philosophers doubt that a theory of consciousness is even possible. They claim that consciousness can never be explained since an object can never understand itself, so we don’t even have the mental firepower to solve this perplexing question. Harvard psychologist Steven Pinker writes, “We cannot see ultraviolet light. We cannot mentally rotate an object in the fourth dimension. And perhaps we cannot solve conundrums like free will and sentience.”

  In fact, for most of the twentieth century, one of the dominant theories of psychology, behaviorism, denied the importance of consciousness entirely. Behaviorism is based on the idea that only the objective behavior of animals and people is worthy of study, not the subjective, internal states of the mind.

  Others have given up trying to define consciousness, and try simply to describe it. Psychiatrist Giulio Tononi has said, “Everybody knows what consciousness is: it is what abandons you every night when you fall into dreamless sleep and returns the next morning when you wake up.”

  Although the nature of consciousness has been debated for centuries, there has been little resolution. Given that physicists created many of the inventions that have made the explosive advancements in brain science possible, perhaps it will be useful to follow an example from physics in reexamining this ancient question.

  HOW PHYSICISTS UNDERSTAND THE UNIVERSE

  When a physicist tries to understand something, first he collects data and then he proposes a “model,” a simplified version of the object he is studying that captures its essential features. In physics, the model is described by a series of parameters (e.g., temperature, energy, time). Then the physicist uses the model to predict its future evolution by simulating its motions. In fact, some of the world’s largest supercomputers are used to simulate the evolution of models, which can describe protons, nuclear explosions, weather patterns, the big bang, and the center of black holes. Then you create a better model, using more sophisticated parameters, and simulate it in time as well.

  For example, when Isaac Newton was puzzling over the motion of the moon, he created a simple model that would eventually change the course of human history: he envisioned throwing an apple in the air. The faster you threw the apple, he reasoned, the farther it would travel. If you threw it fast enough, in fact, it would encircle the Earth entirely, and might even return to its original point. Then, Newton claimed, this model represented the path of the moon, so the forces that guided the motion of the apple circling the Earth were identical to the forces guiding the moon.

  But the model, by itself, was still useless. The key breakthrough came when Newton was able to use his new theory to simulate the future, to calculate the future position of moving objects. This was a difficult problem, requiring him to create an entirely new branch of mathematics, called calculus. Using this new mathematics, Newton was then able to predict the trajectory of not just the moon, but also Halley’s Comet and the planets. Since then, scientists have used Newton’s laws to simulate the future path of moving objects, from cannonballs, machines, automobiles, and rockets to asteroids and meteors, and even stars and galaxies.

  The success or failure of a model depends on how faithfully it reproduces the basic parameters of the original. In this case, the basic parameter was the location of the apple and the moon in space and time. By allowing this parameter to evolve (i.e., letting time move forward), Newton unlocked, for the first time in history, the action of moving bodies, which is one of the most important discoveries in science.

  Models are useful, until they are replaced by even more accurate models described by better parameters. Einstein replaced Newton’s picture of forces acting on apples and moons with a new model based on a new parameter, the curvature of space and time. An apple moved not because the Earth exerted a force on it, but because the fabric of space and time was stretched by the Earth, so the apple was simply moving along the surface of a curved space-time. From this, Einstein could then simulate the future of the entire universe. Now, with computers, we can run simulations of this model into the future and create gorgeous pictures presenting the collisions of black holes.

  Let us now incorporate this basic strategy into a new theory of consciousness.

  DEFINITION OF CONSCIOUSNESS

  I’ve taken bits and pieces from previous descriptions of consciousness in the fields of neurology and biology in order to define consciousness as follows:

  Consciousness is the process of creating a model of the world using multiple feedback loops in various parameters (e.g., in temperature, space, time, and in relation to others), in order to accomplish a goal (e.g., find mates, food, shelter).

  I call this the “space-time theory of consciousness,” because it emphasizes the idea that animals create a model of the world mainly in relation to space, and to one another, while humans go beyond and create a model of the world in relation to time, both forward and backward.

  For example, the lowest level of consciousness is Level 0, where an organism is stationary or has limited mobility and creates a model of its place using feedback loops in a few parameters (e.g., temperature). For example, the simplest level of consciousness is a thermostat. It automatically turns on an air conditioner or heater to adjust the temperature in a room, without any help. The key is a feedback loop that turns on a switch if the temperature gets too hot or cold. (For example, metals expand when heated, so a thermostat can turn on a switch if a metal strip expands beyond a certain point.)

  Each feedback loop registers “one unit of consciousness,” so a thermostat would have a single unit of Level 0 consciousness, that is, Level 0:1.

  In this way, we can rank consciousness numerically, on the basis of the number and complexity of the feedback loops used to create a model of the world. Consciousness is then no longer a vague collection of undefined, circular concepts, but a system of hierarchies that can be ranked numerically. For example, a bacterium or a flower has many more feedback loops, so they would have a higher level of Level 0 consciousness. A flower with ten feedback loops (which measure temperature, moisture, sunlight, gravity, etc.), would have a Level 0:10 consciousness.

  Organisms that are mobile and have a central nervous system have Level I consciousness, which includes a new set of parameters to measure their changing location. One example of Level I consciousness would be reptiles. They have so many feedback loops that they developed a central nervous system to handle them. The reptilian brain would have perhaps one hundred or more feedback loops (governing their sense of smell, balance, touch, sound, sight, blood pressure, etc., and each of these contains more feedback loops). For example, eyesight alone involves a large number of feedback loops, since the eye can recognize color, movement, shapes, light intensity, and shadows. Similarly, the reptile’s other senses, such as hearing and taste, require additional feedback loops. The totality of these numerous feedback loops creates a mental picture of where the reptile is located in the world, and where other animals (e.g., prey) are located as well. Level I consciousness, in turn, is governed mainly by the reptilian brain, located in the back and center of the human head.

  Next we have Level II consciousness, where organisms create a model of their place not only in space but also with respect to others (i.e., they are social animals with emotions). The number of feedback loops for Level II consciousness explodes exponentially, so it is useful to introduce a new numerical ranking for this type of consciousness. Forming allies, detecting enemies, serving the alpha male, etc., are all very complex behaviors requiring a vastly expanded brain, so Level II consciousness coincides with the formation of new structures of the brain in the form of the limbic system. As noted earlier, the limbic system includes the hippocampus (for memories), amygdala (for emotions), and the thalamus (for sensory information), all of which provide new parameters for creating models in relation to others. The number and type of feedback loops therefore change.

  We define the degree of Level II consciousness as the total number of distinct feedback loops required for an animal to interact socially with members of its grouping. Unfortunately, studies of animal consciousness are extremely limited, so little work has been done to catalog all the ways in which animals communicate socially with one another. But to a crude first approximation, we can estimate Level II consciousness by counting the number of fellow animals in its pack or tribe and then listing the total number of ways in which the animal interacts emotionally with each one. This would include recognizing rivals and friends, forming bonds with others, reciprocating favors, building coalitions, understanding your status and the social ranking of others, respecting the status of your superiors, displaying your power over your inferiors, plotting to rise on the social ladder, etc. (We exclude insects from Level II, because although they have social relations with members of their hive or group, they have no emotions as far as we can tell.)

  Despite the lack of empirical studies of animal behaviors, we can give a very rough numerical rank to Level II consciousness by listing the total number of distinct emotions and social behaviors that the animal can exhibit. For example, if a wolf pack consists of ten wolves, and each wolf interacts with all the others with fifteen different emotions and gestures, then its level of consciousness, to a first approximation, is given by the product of the two, or 150, so it would have Level II:150 consciousness. This number takes into account both the number of other animals it has to interact with as well as the number of ways it can communicate with each one. This number only approximates the total number of social interactions that the animal can display, and will undoubtedly change as we learn more about its behavior.

  (Of course, because evolution is never clean and precise, there are caveats that we have to explain, such as the level of consciousness of social animals that are solitary hunters. We will do so in the notes.)

  LEVEL III CONSCIOUSNESS: SIMULATING THE FUTURE

  With this framework for consciousness, we see that humans are not unique, and that there is a continuum of consciousness. As Charles Darwin once commented, “The difference between man and the higher animals, great as it is, is certainly one of degree and not of kind.” But what separates human consciousness from the consciousness of animals? Humans are alone in the animal kingdom in understanding the concept of tomorrow. Unlike animals, we constantly ask ourselves “What if?” weeks, months, and even years into the future, so I believe that Level III consciousness creates a model of its place in the world and then simulates it into the future, by making rough predictions. We can summarize this as follows:

  Human consciousness is a specific form of consciousness that creates a model of the world and then simulates it in time, by evaluating the past to simulate the future. This requires mediating and evaluating many feedback loops in order to make a decision to achieve a goal.

  By the time we reach Level III consciousness, there are so many feedback loops that we need a CEO to sift through them in order to simulate the future and make a final decision. Accordingly, our brains differ from those of other animals, especially in the expanded prefrontal cortex, located just behind the forehead, which allows us to “see” into the future.

  Dr. Daniel Gilbert, a Harvard psychologist, has written, “The greatest achievement of the human brain is its ability to imagine objects and episodes that do not exist in the realm of the real, and it is this ability that allows us to think about the future. As one philosopher noted, the human brain is an ‘anticipation machine,’ and ‘making the future’ is the most important thing it does.”

  Using brain scans, we can even propose a candidate for the precise area of the brain where simulation of the future takes place. Neurologist Michael Gazzaniga notes that “area 10 (the internal granular layer IV), in the lateral prefrontal cortex, is almost twice as large in humans as in apes. Area 10 is involved with memory and planning, cognitive flexibility, abstract thinking, initiating appropriate behavior, and inhibiting inappropriate behavior, learning rules, and picking out relevant information from what is perceived through the senses.” (For this book, we will refer to this area, in which decision making is concentrated, as the dorsolateral prefrontal cortex, although there is some overlap with other areas of the brain.)

  Although animals may have a well-defined understanding of their place in space and some have a degree of awareness of others, it is not clear if they systematically plan for the future and have an understanding of “tomorrow.” Most animals, even social animals with well-developed limbic systems, react to situations (e.g., the presence of predators or potential mates) by relying mainly on instinct, rather than systematically planning into the future.

  For instance, mammals do not plan for the winter by preparing to hibernate, but largely follow instinct as the temperature drops. There is a feedback loop that regulates their hibernation. Their consciousness is dominated by messages coming in from their senses. There is no evidence that they systemically sift through various plans and schemes as they prepare to hibernate. Predators, when they use cunning and disguise to stalk an unsuspecting prey, do anticipate future events, but this planning is limited only to instinct and the duration of the hunt. Primates are adept at devising short-term plans (e.g., finding food), but there is no indication that they plan more than a few hours ahead.

  Humans are different. Although we do rely on instinct and emotions in many situations, we also constantly analyze and evaluate information from many feedback loops. We do this by running simulations sometimes even beyond our own life span and even thousands of years into the future. The point of running simulations is to evaluate various possibilities to make the best decision to fulfill a goal. This occurs in the prefrontal cortex, which allows us to simulate the future and evaluate the possibilities in order to chart the best course of action.

  This ability evolved for several reasons. First, having the ability to peer into the future has enormous evolutionary benefits, such as evading predators and finding food and mates. Second, it allows us to choose among several different outcomes and to select the best one.

  Third, the number of feedback loops explodes exponentially as we go from Level 0 to Level I to Level II, so we need a “CEO” to evaluate all these conflicting, competing messages. Instinct is no longer enough. There has to be a central body that evaluates each of these feedback loops. This distinguishes human consciousness from that of the animals. These feedback loops are evaluated, in turn, by simulating them into the future to obtain the best outcome. If we didn’t have a CEO, chaos would ensue and we would have sensory overload.

  A simple experiment can demonstrate this. David Eagleman describes how you can take a male stickleback fish and have a female fish trespass on its territory. The male gets confused, because it wants to mate with the female, but it also wants to defend its territory. As a result, the male stickleback fish will simultaneously attack the female while initiating courtship behavior. The male is driven into a frenzy, trying to woo and kill the female at the same time.