Part 8 (1/2)
This intuitive belief in separateness allows you to be able to consider all sorts of situations without getting a brain ache, as you would if I started to explain quantum physics. When Susie says, ”If I could just be a fly on the wall in that office for an hour!” you immediately know she wants to be a physical fly but retain her own mind. The fly would not only have a desire and intention, it would have her desire and goal and intention to listen to what was being said. You can easily separate her physical self from her mind and put her mind into the fly. A real fly would have no such state, but the idea is easy to comprehend. You also don't hear someone saying, ”If I could just be a wall for an hour!” because it is less likely for your intuitive psychology to a.s.sign an inanimate object, a wall, the ability to have desires and goals.
Because you can mentally separate the physical body from the invisible essence of a person, you can conceive that either one could exist separately. The physical body without the essence is a zombie, a robot; the invisible essence without the body is the soul or spirit. We can conceive of other essences or invisible agents without a physical body that have desires or intentions, such as ghosts, spirits, angels, demons or the devil, and G.o.ds or G.o.d. It would follow from Povinelli's reasoning, then, if animals cannot form concepts of imperceptible ent.i.ties or processes, if they do not possess a full TOM, then they cannot be dualists nor entertain the notion of spirits of any sort. These are uniquely human qualities. But what about the stories of elephants visiting their dead relatives? Doesn't that mean that they have some notions of essences?
ARE WE THE ONLY DUALISTS?.
The search for evidence of dualism in the animal world has centered on how a species treats their dead. Humans attach great importance to dead bodies, and their observable ritualistic behavior a.s.sociated with the dead is visual indication of dualism at work. Although Neanderthals occasionally buried their dead, Cro-Magnons (the first anatomically modern h.o.m.o sapiens who appeared in Europe, about forty thousand years ago) regularly and elaborately did, interring with them material objects. This indicates a belief in an afterlife where such items were a.s.sumed to be useful.42 A belief in an afterlife a.s.sumes that there is a difference between the physical body that is buried in the ground and what continues to live on. The Cro-Magnons were dualists.
So, do other animals show an elaborate response to their dead relatives or companions? Most animals do not. Lions appear to be practical. They may briefly sniff or lick the body of a recently dead buddy, and then tuck in to it for a quick meal. Chimps may have longer interactions with a dead social partner, but they abandon the body once it starts getting a little whiffy.43 However, elephants have been observed to behave quite differently. Cynthia Moss, who started the Amboseli Elephant Research Project at Amboseli National Park in Kenya, has studied African elephant family structure, life cycle, and behavior. In her book Elephant Memories, she wrote: Unlike other animals, elephants recognize one of their own carca.s.ses or skeletons...when they come upon an elephant carca.s.s they stop and become quiet and yet tense in a different way from anything I have seen in other situations. First they reach their trunks toward the body to smell it, and then they approach slowly and cautiously and begin to touch the bones...they run their trunk tips along the tusks and lower jaw and feel in all the crevices and hollows in the skull. I would guess they are trying to recognize the individual.
Although the reports of elephant graveyards had been exposed as myths,43 Moss and other researchers suggested that they visited the dead bones of their relatives.44 But did they? Did they visit or recognize dead individuals? Karen McComb and Lucy Baker, from the University of Suss.e.x, United Kingdom, joined Moss to study this question experimentally. In one experiment, they set out an elephant skull, a piece of ivory, and a piece of wood. They found the elephants were very interested in the ivory, and were also somewhat interested in the elephant skull, but not the wood. In another experiment, the researchers found that they were more interested in an elephant skull than in the skull of a buffalo or a rhino. In their last experiment, they found that the elephants showed no preference for the skull of their own matriarch over the skulls of matriarchs from other clans.43 What does this tell us? It tells us that elephants are very interested in ivory and are more interested in the bones of their own species than those of others, but not specifically the bones of a relative. What the significance of this preference is, both evolutionarily and behaviorally, is currently unknown, but it cannot be taken for evidence that elephants have an interest in their conspecifics beyond the physical. Whether there are other species that practice a similar behavior still needs to be checked out.
REFLECTIVE BELIEFS.
After all this incoming information from the senses has been selectively picked apart and processed by various intuitive systems and your memory, some of it comes bubbling into your conscious mind. How that happens is still the big mystery. Once the info hits the conscious mind, the interpreter comes in-Mr. Know-it-all, who puts the info together and makes sense out of it. All this detecting, profiling, and predicting is done automatically. It is quick and fast, and usually correct. However, it is not always correct. Sometimes the detective gets it wrong-for instance, when you hear the rustle in the bushes and jump because your ”who or what did that?” detective goofed and told you it was an animal that caused the noise instead of the wind. That's OK. It is better to be fast and sometimes wrong than slow and mostly right. Or maybe your detective goofed and identified your computer as alive because it did something all by itself (that you couldn't possibly have caused) and so your profiler gave it theory of mind. Now you believe that it has desires causing its behavior, and the interpreter has to make sense of this, so it comes up with: Your computer is out to get you! All this is your automatic nonreflective belief system at work, fed by information from different domains.
But just because you can imagine something does not mean it is true. You can imagine a unicorn, a satyr, and a talking mouse. Just because you believe something does not mean that it is true. Just because you believe or imagine that the mind and body are separate does not mean they are. So, what happens now when I pose a problem to you that challenges your nonreflective beliefs? If you believe that the mind and body are separate, that you have a soul that is more than just your brain cells and chemicals, then how do you explain personality changes, consciousness changes, or any of the changes that occur with brain lesions? What about Phineas Gage, who after his brain injury was described as no longer the same person? His essence was different because of a physical change in his brain. Now you have to think this over and decide if you are going to change your mind or not.
Reflective beliefs are different and are probably what most people mean when they say they believe something. Reflective beliefs make up opinions and preferences. They are not fast and automatic but are conscious and take time to form, and may or may not agree with nonreflective beliefs. After you weigh the information, look at the evidence, and consider the pros and cons, you come to a decision whether to believe something or not. Yeah, sure, we learned in chapter 4 just how far in depth most people will go in this endeavor and how difficult it is to form rational judgments. Reflective beliefs are the same. Just as with moral judgments, they too are usually arrived at with a minimum of reflection. Both reflective and nonreflective beliefs can be either true or false, and may or may not be provable or justifiable.
The interesting difference between these two types of belief systems is how to tell which is in effect. Usually, if the automatic nonreflective, nonconscious belief system is in effect, you can tell by the person's behavior, whereas the best evidence for a conscious belief system is verbal statements, which may or may not be consistent with his or her behavior. You still walk faster by the cemetery at night even though you say you don't believe in ghosts. You still act as if we are talking to a mind rather than a bunch of cells and chemicals, even if you think there is no difference between a brain and a mind, a body and a soul.
Barrett tells us how nonreflective beliefs affect reflective ones. To begin with, nonreflective beliefs are the default mode. If you have never been presented with a situation in which you must question your nonreflective belief, then that is what you will believe. It is not until you learn about Venus flytraps that you will change your intuitive belief that plants are not carnivorous, and it is not until you learn about the sensitive plant that you will change your belief that plants don't move on their own. Your intuitive beliefs are best guesses. These two types of plants are rare, so your best guess that plants aren't carnivores and don't move will serve you well. This is much easier than holding a piece of ham in front of every new plant you see to determine if it is a carnivore.
Next, the better a reflective belief merges with a nonreflective belief, the more plausible it seems, the more intuitive and the easier to learn or accept. If I tell you a table is a solid object that doesn't move, that accords with your intuitive beliefs about objects that are not alive. That is easy to believe. However, if a physicist tells you that no objects are solid but are just a bunch of atoms moving around, that is difficult to believe. Just as when arriving at moral judgments, if the reflective belief verifies how you already see the world, it is more readily accepted. The other way that nonreflective beliefs influence reflective ones is that they shape memory and experience. When you form a memory, first you have perceived something. Zip, the perception gets funneled through your detectives and profilers, all picking out and editing the info. The interpreter puts it all together in a summary that makes sense and files it away in memory. It has already been edited by your nonreflective belief system, and you are now calling on it as true information to use for forming a reflective belief. This information may be totally wrong, and is the same as using anecdotal evidence to form a moral judgment in which you may attribute the wrong cause to the effect. Not only that, once you form a reflective belief based on this information, then that reflective belief, if it meshes with another reflective belief, will be even stronger or will supply strength for another reflective belief.
If my friend tells me she is afraid of heights and asks me if I am, in order to answer I may remember standing at the edge of the Grand Canyon and getting the catecholamine rush that gave me a feeling of fear. My brain interpreted this feeling as being caused by standing on the rim of the canyon, but its actual cause was the catecholamine rush. In fact, it may not have been standing on the rim that gave me the rush; it may have been a memory of falling off a ladder that occurred to me as I leaned out over the canyon. The actual reason for the rush is not what you become aware of; it is your brain's interpretation of the rush. It may not be the correct interpretation, but it will fit the circ.u.mstances. Now you have a false belief. You think the feeling of fear was caused by standing on the rim of the canyon. This false belief can now be used in the future when you consciously reflect about heights. You will remember that you were scared standing there, and this memory may cause you to stay away from high places and form the reflective belief that you are afraid of heights.
Reflective beliefs need more time. If I force you to respond to a question within a few seconds, you will be more likely to respond with your nonreflective belief.45 So in the rare event when we are being ”deep” because a default nonreflective belief hasn't presented itself, or for some reason we are questioning an automatic belief, and we actually are spending time pondering to form what we so blithely think of as an informed belief, much of the information that we use from memories and past experience is highly colored by our nonreflective intuitive beliefs, and some of it can be wrong. It is very difficult to separate the intuitive from the verifiable, even though that is what we think we are doing. It would be like doing a math problem that involves several steps, and getting the first step's answer wrong but being quite sure it was correct, and using it to complete the rest of the problem. And don't forget how emotion gets to be part of the process. What a mess!
Luckily, the whole process has been refined to enhance fitness and survival, and usually it gets things right enough, but not always. Or I should say it got things right enough in the evolutionary environment. To separate the verifiable from the nonverifiable is a conscious, tedious process that most people are unwilling or unable to do. It takes energy and perseverance and training. It can be counterintuitive. It is called a.n.a.lytical thinking. It is not common and is difficult to do. It can even be expensive. It is what science is all about. It is uniquely human.
So we have this generally well-run system that sometimes makes errors, and these errors can lead to some mistaken beliefs. As the old adage goes, ”Actions speak louder than words.” Our actions tend to reflect our automatic intuitive thinking or beliefs. We are dualists because our brain processes have been selected over time to organize the world in specific categories and a.s.sign different properties to these categories. It just so happens we ourselves fall into two separate categories whose properties are different. We are animate objects, which are subject to the physical laws of animate objects, but we also have nonperceptual psychological properties not subject to physical laws. No problem! We'll take a little of this and a little of that and voila: a physical biological body and an un.o.bservable psychological essence, two things in one. As Descartes would have said, ”Pas de probleme!”
CONCLUSION.
We have seen that both we and other animals share some highly domain-specific abilities, such as spooking at snakes and recognizing other predator animals. We also share some of our intuitive physics with other animals, such as object permanence and gravity, and as we have seen in previous chapters, some rudimentary intuitive psychology (TOM). However, species differ in their domain specificities. Unlike other animals, we humans have an expanded intuitive understanding of physics. We understand that there are invisible forces. Current evidence suggests that we are the only animals that reason about un.o.bservable forces. We alone form concepts about imperceptible things and try to explain an effect as having been caused by something. We also use these same abilities of reasoning about and explaining imperceptible things in the biological and psychological arenas. We understand that other living things have an invisible essence that is independent of their appearance, although we may get carried away with just what this essence is. This questioning and reasoning about imperceptible forces is a hugely significant ability. It certainly sparked the curiosity that, when coupled with conscious a.n.a.lytical thinking, has been the cornerstone of science, but that same curiosity has led to other, less rigorous ways of explaining imperceptible forces, such as myths, junk science, and urban legends.
Chapter 8.
IS ANYBODY THERE?.
As the brain changes are continuous, so do all these consciousnesses melt into each other like dissolving views. Properly they are but one protracted consciousness, one unbroken stream.
-William James, The Principles of Psychology, 1890.
EVER SINCE MY DAYS IN COLLEGE, I HAVE PUZZLED OVER THE problem of conscious awareness. This isn't a story about college bull sessions dealing with the meaning of life. This is a story about my being fascinated with my college buddies. You see, I was a member of the fabled Animal House at Dartmouth College, and I was Giraffe. What a ride that was.
Actually, I was pretty square until Green Key Weekend of my junior year. I had a deal with my father. No booze until twenty-one and he would write me a check for five hundred bucks. But my frat brothers told me a great drink was grapefruit juice and vodka. So, emboldened with the idea of the moment, I dove into my first drink. It was a hot day, and about five drinks later, I declared there wasn't much to this drinking thing, stood up from the sofa, took one step, and pa.s.sed out.
Of course, the real lesson was about changing the normal conscious state of a twenty-year-old. Why do we love to change our consciousness, our appreciation and feelings about the world around us? We drink, we smoke, we do lattes, we seek painkillers, we may even get runner's high. We are always tampering with an aspect of our existence we still can't define: phenomenal conscious experience.
Consciousness comes in many flavors. Anyone who has taught an introductory college cla.s.s, or attended one at eight o'clock Friday morning, has seen them all. There may be a couple of party-hearty frat boys in the back row, dozing after a long night spent celebrating the upcoming weekend. These two are not conscious. Up a couple of rows is the scammer checking out the hot babe across the aisle and wondering if he can get a date. He is conscious, but not of you; nor are the three girls down the way who are pa.s.sing notes to each other and suppressing their merriment. Another has a tape recorder going and is finis.h.i.+ng up a paper for another cla.s.s, and will be conscious of you later. The front-row kids are sippin' their coffee, taking notes furiously and occasionally nodding in agreement; at least they are conscious of you. Although most people don't sit around and ponder the question of consciousness, they talk about it a lot. After cla.s.s you may overhear: ”I finally realized [was conscious of ] what a jerk he was, like, he totally didn't even pay any attention to what I was saying and was only conscious of the sports channel. Great if you are into football stats, but if you want him to [be conscious of and] remember your birthday, forget about it. I, like, totally dumped him.”
We have talked a lot about two aspects of brain function: the nonconscious goings on and the conscious goings on, the latter being what researcher Michael Posner at the University of Oregon calls alertness. We have already seen that a considerable amount of processing, one might even want to say most of it, occurs without our being aware of it: undercover. It hasn't been easy figuring out the content of all the nonconscious goings on that have been elucidated so far, for the simple reason that it doesn't bubble up to our consciousness. Researchers have had to devise tricky experiments to reveal their presence.
This might lead one to think that studying consciousness may be a little easier. Yet, as French neuroscientists Stan Dehaene and Lionel Naccache point out, the object of our study is now introspective and not an objectively measurable response.1 Oddly enough, subjective reports of introspection themselves give us some clues. My studies with split-brain patients have revealed that introspection can be wrong.2 We actually unwittingly make up stories to fit the observable phenomenon, but this very fact is also a clue, which we will look into a bit later. Our very dualistic nature has also been a stumbling block on the road to unlocking the mechanisms of consciousness.3 There are those who feel that the essence of consciousness cannot have a physical explanation, that it is so wondrous that it can't be explained by modules and neurons and synapses and neurotransmitters. We will soldier on without them. There are others who think that it can be. I find that being able to explain consciousness with modules, neurons, synapses, and neurotransmitters is even more wondrous and fascinating. It may not be glamorous and transcendent, but it sure is captivating.
THE UNSOLVED MYSTERY.
One of the mysteries of consciousness is how a perception or information enters into consciousness from the nonconscious depths. Is there a gatekeeper that lets only some information through? What information is allowed through? What determines that? What happens after that? How do new ideas form? What processes are contributing to consciousness? Are all animals equally conscious or are there degrees of consciousness? Is our consciousness unique? The question of consciousness has been rather like the holy grail of neuroscience. If you tell me you are interested in knowing just exactly what parts of the brain are active when you are conscious of something-a flower, a thought, a song-what you are asking about is known as the neural correlates of consciousness (NCC). You are not the lone coyote on this quest. No one knows exactly what is going on, but there are plenty of suggestions. So let's see how many of those questions have been answered and what the theories are about the rest.
Many researchers have proposed definitions and criteria for different levels of consciousness, to the point where it has gotten rather confusing.4, 5 Progressive levels of consciousness are commonly named unconsciousness, consciousness, self-awareness, and meta-self-awareness, which means you know that you are self-aware.
Antonio Damasio6 takes out his scalpel and slices consciousness down even further to only two choices: core consciousness and extended consciousness. Core consciousness is what goes on when the on-off switch is flipped on and an organism is awake and aware of one moment, now, and one place, here. It is alert and not concerned with the future or the past. This consciousness is not aware of self and is not uniquely human. It is, however, the foundation that is necessary to build increasingly complex levels of consciousness, which Damasio calls extended consciousness. Extended consciousness is what we normally think of when we think of being conscious. Extended consciousness is complex and is made up of many levels. For instance, one level of consciousness is being aware of one's surroundings and the chocolate cake on the table. Another is being aware of them and knowing they are different from yesterday and may be different tomorrow. (The cake wasn't there yesterday, and most likely will be gone tomorrow, so dig in now!) These aspects of consciousness have to do with content, the components of conscious experience. The highest level is knowing that one is aware of one's surroundings and, I might add, what that cake will do to your waistline, and caring. I know for sure that dogs do not care about their waistlines. This involves the autobiographical self.
What we want to know is whether there is a systematic way that information processing reaches consciousness, and if so, what it is, how it works, and what aspects of this system may be uniquely human. To figure this out, we are going to start with some rough neuroanatomy, including what has been learned from persons with different brain lesions and from neuroimaging studies. Then we are going to look at some theories.
THE PHYSICAL BASIS OF CONSCIOUS EXPERIENCE.
First, we need to know what brain areas are needed for core consciousness-the ”on” switch. It begins in the brain stem. The brain stem* is the lower part of the brain, structurally continuous with the spinal cord, the first station on the way to the cortex. It is a structure that is evolutionarily old. All vertebrate animals have a brain stem, but they are not all made up of the same types of neurons. The brain stem is a complicated place. It is like all those subbas.e.m.e.nts in skysc.r.a.pers, full of pipes, vents, wires, and gauges, which are connected to the rest of the building. They keep everything running smoothly, but no one up on the thirty-fourth floor even thinks about them. If you were to disconnect some of the wiring, then the thirty-fourth floor would know something was amiss, whether it was the lights, the AC, or the telephones. If you were to disconnect all the wires, everything would shut down.
Just like the guy on the thirty-fourth floor, you have no idea what is going on in your brain stem. You are not conscious that different groups of neurons, known as nuclei, are relaying signals from your entire body related to the current state of your guts, heart, lung, balance, and musculoskeletal frame to parts of the brain higher up, with connections that are both sending and receiving information in the form of impulses. The main job of these brain-stem nuclei is the homeostatic regulation of both body and brain. They are fundamental for cardiovascular, respiratory, and intestinal control. Disconnect the brain stem, and the body dies. This is true for all mammals.
These groups of neurons have their dendrites in many pies. Some are required for consciousness, and those are connected with the intralaminar nuclei (ILN) of the thalamus. Others are required to modulate consciousness, like a rheostat; they make up part of the arousal system. These are connected to the basal forebrain, the hypothalamus, and directly to the cortex.7 Our party-hearty boys are not irreversibly unconscious. We can pinch them or throw cold water on them, and they will wake up. Their consciousness was being modulated by the arousal system via the connections that pa.s.s on to the basal forebrain and the hypothalamus.
Core consciousness is the first step to extended consciousness. If the wiring for core consciousness is disconnected, the pinch or the cold water will not bring anyone back to wakefulness. This is where the neurons that connect the brain stem with the intralaminar nuclei of the thalamus are the stars. There are two ILNs in the thalamus, one in the right side and one in the left. The thalamus itself is about the size of a walnut and sits astride the midline, smack dab in the center of the brain. Small, strategically placed bilateral lesions to the ILN in the thalamus turn consciousness off forever, although a lesion in one alone will not.8 If the ILNs of the thalamus don't get their input from the connections to the brain stem, they are likewise kaput. So we have the first step on the road to consciousness: The connection of the brain stem to the thalamus must be active, and at least one of the ILNs must be up and running.
Where do the pathways from the brain stem go beyond the ILNs? Wherever they go, some must be involved with consciousness also. Now the thalamus, of which the ILNs are a part, is a well-connected dude. Neuronal connections link it to specific regions all over the cortex, and those regions send connections straight back to the thalamus. It has connection loops, which will become important a little later on in our discussion. The ILNs themselves connect to the anterior portion of the cingulate cortex. Lesions anywhere from the brain stem to the cingulate cortex can disrupt core consciousness.
It appears that the cingulate cortex is where core consciousness and extended consciousness overlap. The cingulate cortex sits on top of the corpus callosum, the great bundle of neurons that connects the right and left hemispheres. Damasio reports that patients with lesions in their cingulate cortex have disruptions in both core and extended consciousness, but oftentimes can recover core consciousness.