WE ALL ACT LIKE DUALISTS: THE CONVERTER FUNCTION - THE GLORY OF BEING HUMAN - Human: The Science Behind What Makes Us Unique - Michael S. Gazzaniga

Human: The Science Behind What Makes Us Unique - Michael S. Gazzaniga (2008)



The centermost processes of the brain with which consciousness is presumably associated are simply not understood. They are so far beyond our comprehension that no one I know of has been able to imagine their nature.

Roger W. Sperry, quoted by Denis Brian in Genius Talk: Conversations with Nobel Scientists and Other Luminaries

IN THE PERSONAL ADS IN THE DATING COLUMNS, WHEN PEOPLE will describe themselves or the type of person they are looking for, there might be a quick physical description such as “tall, brown eyes, brown hair, thin, athletic,” but then the writer will launch into “humorous, clever, intelligent, and happy male looking for witty, charming, intelligent, caring, generous female,” or something similar. These descriptions don’t seem odd. It would seem odd if there were no description of the personality or character of either party, but instead the physical description continued, “I have a 5 percent greater amount of gray matter than average, and my left planum temporale is larger than most. I have spent years increasing my intercerebral connectivity, to the point where my latest scan rather stunned the radiographers. I am looking for someone with a large cerebellum and hippocampus, and a well-connected amygdala. Please do not respond if you have had any prefrontal lobe injuries.”

Although perhaps some specialists could guess the characteristics that such a brain might endow on its person, it is not how we think about others. If you are talking with a friend and tell him about your son, you don’t start with his physical description. You may say what a great kid he is and what his interests are and whether he likes school or sports. Sure, you will probably pull out his picture, but the conversation is not dead without it. You are talking about what makes him him. If you merely said, “Ah, let’s see, he has blond hair and is about four eleven now, and he burns easily,” that would not tell us much about him except that he should use sunblock, and you would likely get some speculative looks.

There seem to be two parts of a person, the physical person (the body, including the brain), and then that other part, the part that makes you you and me me—the essence. Some call this the soul or spirit; others call it the mind. Together, these make up the classic mind/body duo. Philosophers have been discussing and arguing for literally thousands of years whether the mind and body are one entity or are separate, with Descartes topping the charts championing the latter position. Dualism is the belief that people are more than just bodies. This idea comes so easily to us that we even believe it about other animals, especially our pets and any animal we consider cute.

But you know what? We are not going to talk about whether the mind and body are the same or separate in reality. We are going to talk about why most people believe they are separate and why even people who don’t believe they are separate act as if they are separate. Why do we think of a person as being more than just a body? Maybe in a conscious intellectual way, you can grasp the idea that you are just a bunch of atoms and chemical reactions, but in everyday life, that is not how you interact. If someone cuts in front of you on the freeway, you don’t think, Gee, what an influx of catecholamines in that chunk of cells in front of me! No, you think, What makes him think he is so important that he should get in front of me? What a jerk. And if you are standing on the rim of the Grand Canyon looking over the edge and get a rush of catecholamines yourself, you don’t say, Whoa, I’ve got some palpitations going on. Great catecholamine surge. No, the chemical change produces a feeling that your brain is compelled to explain situationally. It takes into account all the input, and then interprets the feeling and comes up with, Standing on the edge here makes me nervous.

What happens in every instance of human life? We somehow reflexively convert raw input, such as what we experience and see and feel, into another level of organization. In physical terms, it is like a phase shift, like going from solid to liquid to gas. Each state has its rules, its references, its reality. So too for the work of the brain. Mental states come with the brain, whether you want them or not. Our converter takes the input and delivers it to a new organization. Our chore in this chapter and also in the next is to try to understand the converter functions, the system that makes us all dualists.

Of course, we immediately want to know, Are we the only dualists? Is your cat a dualist? Does your cat think that you are more than his person who feeds him? Does he separate the you that he sees and smells and hears and licks and scratches and bites to some incorporeal you?

We are going to probe how the human brain forms beliefs, and what makes the belief that we have a mind that is separate from the body so easy to latch on to. The systems our brain uses to form beliefs and the way our brain forms the belief that we are dual are both central to the understanding of what makes us unique.

As we have seen with other systems, belief formation comes in two flavors. Neuropsychologist Justin Barrett calls these two systems reflective and nonreflective.1 Nonreflective beliefs are fast and automatic. Sound familiar? These are such common thoughts that you may not even classify them as beliefs. You are sitting at the kitchen table having breakfast, still half asleep. You knock your knife onto the floor. Do you believe the knife felt pain? Could the knife have just as easily hit the ceiling or passed through the floor into the ground under the house? How about the floor; will it bleed? After you pick up the knife, wash it off, and put it in the drawer, do you think it will mate with the other knives? Will there be twice as many knives in the drawer in a few days? No. You don’t believe any of that, and you don’t even have to think about those questions to give me an answer, even though you may never have thought about any of them before.

As you stare out the window at breakfast without your glasses on, you see something about the size of a softball come down out of the sky, land on the tree branch, and start making a tweeting noise. Do you believe it is breathing? Do you believe it gets hungry? Do you think it mates? Do you believe one day it will die? Sure you do. Your brain has classified these two different items into two different categories. One was “a thing” and the other was “It’s alive!” Then your brain automatically inferred an entire list of properties that belong to each category, beginning with “object, not alive” and “object, alive, animal.” This makes life much easier for us.

You wouldn’t want to have to consciously go through a whole list of properties every time you came across something you hadn’t seen before and have to learn them each time. You would never get out of Home Depot. None of us would be here, because our ancestor would have been transfixed, staring at the lion and running down a list of alternatives still figuring out what it was that was flying through the air toward his throat. Your brain has used its detection devices to figure out the categories your perceptions fall into. You have an entire detective agency working in your brain, made up of an object detection device, an animal identifier, an artifact identifier, and a “face detector,” all of which answer the question, Who or what is that? You also have an agency detection device, the detective that answers the question, What or who done it? You also have profilers working. Once the detective devices identify the culprit, the profilers infer information about it and describe it. Barrett calls these profilers an animal describer, an object describer, a living thing describer, and an agent describer (also known as TOM). Each of these detectives and profilers has some hardwired knowledge, and as you learn and experience the world, this knowledge gets enhanced. All of these devices are part of the converter function that leads to our moving things from one level or state into the personal psychological state. How such devices actually work is not altogether clear, and we will talk more about that in chapter 8. For now, let’s see what is hardwired.


Humans are natural-born taxonomists. We like to name and categorize all sorts of objects that surround us, and our brain automatically does this. A good rule of thumb is, if a way of thinking comes easily to us, we probably have some cognitive mechanism that is set up to think in that way. Cognitive anthropologist Scott Atran from the University of Michigan provides evidence that in every human society people intuitively think about plants and animals in the same special ways,2 which are different from how we think about objects, such as rocks or stars or chairs. An animate object is different from an inanimate object. The intuition that bestows animacy on an object is the hardwired knowledge that animate objects have, as Steven Pinker so wonderfully refers to it, “an internal and renewable source of oomph.”3 We classify plants and animals into species-like groups and infer that each species has an underlying causal nature, or essence, which is responsible for its appearance and behavior.

This essence is the nonperceptual attributes that make a wolf a wolf, even if it is in sheep’s clothing—for appearance is not always reality. We know that a horse is still a horse, even if you paint zebra stripes on it. This belief or intuition is already present in preschool children. These kids will tell you that if you change the innards, those invisible parts of dog, it no longer is a dog, but if you change its appearance, it still is; and once you’re born something, such as a cow, you will develop the nature and behavior of that animal, no matter if you were raised by pigs and never saw another cow.4 These classification systems have a hierarchy. There are groups within groups: A mallard is a specific type of duck, which is a specific type of bird. The classification provides a framework for making inferences about the properties of the category.5 Some of the inferences are innate, some are learned. You tell me it’s a bird, I infer it has feathers and can fly. You tell me it’s a duck, I infer it has feathers, flies, quacks, and swims, and I may even infer that its name is Donald. You tell me it’s a mallard, and I infer all that, plus the fact that it will be in my backyard in March. Intuitive biology refers to this way our brains categorize living things.

Harvard researchers Alfonso Caramazza and Jennifer Shelton claim that there are domain-specific knowledge systems for animate and inanimate categories that have distinct neural mechanisms. Indeed, there are patients with brain damage who are very poor at recognizing animals but not man-made artifacts, and vice versa.6 If you have a lesion in one spot, you can’t tell a tiger from an Airedale, and if it is in another spot, the telephone becomes a mysterious object. There are even people with brain lesions that make them specifically unable to recognize fruit.

How do these systems work and come about? If an organism repeatedly comes across the same situation, any individual that evolves a mechanism to understand or predict the results of the situation is going to have a survival advantage. These domain-specific knowledge systems aren’t actually the knowledge itself, but systems that make you pay attention to particular aspects of situations that will increase your specific knowledge. Just how specific and what type of information is encoded are not the same for every system, and there are different opinions on how it is differentiated.

Clark Barrett and Pascal Boyer suggest that the animal identification system may be a bit more specific than the object system, especially for predators as opposed to prey animals.7 Within the domain of living things, there may be quite specific detectors for certain classes of dangerous animals that were common in many environments, such as snakes, and perhaps even big cats. A stable set of visual clues may be encoded in the brain, clues that make you pay attention to such things as sharp teeth, forward-facing eyes, body size and shape, and aspects of biological motion that are used as input to identify them.8 You don’t have innate knowledge that a tiger is a tiger, but you may have innate knowledge that when you see a large stalking animal with forward-facing eyes and sharp teeth, it is a predator. Once you see a tiger, then you pop that into the predator category along with whatever else you have already added.

This domain specificity for predators is not limited to humans. Richard Coss and colleagues at the University of California, Davis, have studied some squirrels that had been raised in isolation with no previous exposure to snakes. When exposed to snakes for the first time, they evaded them but did not evade other novel objects. They concluded that these squirrels have an innate wariness of snakes. In fact, these researchers have been able to document that it takes ten thousand years of snake-free living for this “snake template” to disappear from populations.9 I am pretty sure I have a big fat snake template.

Dan Blumstein and colleagues at UCLA have studied a group of tammar wallabies living on Kangaroo Island, off the coast of Australia, that have been naturally isolated from all predators for the last 9,500 years. They presented these wallabies with stuffed predators that were evolutionarily novel (ones their ancestors had never faced—a fox or cat), as well as a model of their evolutionary, though now extinct, predator (no stuffed ones being available). The wallabies responded to the sight of both types: They stopped foraging and became more vigilant.10 They did not have these reactions to the control items. They were reacting to some visual cue that these stuffed or model predators exhibited, not to any behavior. Thus, it is possible for highly domain-specific mechanisms to exist, in this case for identification, ones that do not require prior experience or social context to work. These mechanisms are innate and hard-wired. We share some with other animals, certain animals have some that we don’t have, and some are uniquely human.

Studying babies helps us identify what knowledge is hardwired in humans. In a previous chapter, we learned that babies have categorizing domain-specific neural pathways to identify human faces and also to register biological motion.11 There are a couple of other aspects of motion that interest babies from about nine months of age and aid in identifying animate motion. Babies understand when an object reacts to a distant event. For instance, if something falls, whatever else moves that it did not contact is animate.12 They also expect an animate object to move toward a goal in a rational way.13 So if an object has to hop over an obstacle to get to a goal, they expect it not to hop if the obstacle is removed. Infants have even been shown to have specific expectations about what objects that are chasing or evading will do.14 These studies are all evidence that young infants have innate abilities to distinguish animate from inanimate objects. So, once an object is observed with any of these perceptual characteristics, the detective device surmises that it’s ALIVE, and the brain automatically places it in the alive category and then infers a list of properties. The more life experience you have, the more you add to the list of properties that you infer. If none of these characteristics are observed, it will be placed in the inanimate category, and a different set of properties will be inferred. This is where the profilers come in.

Infers properties? Yes! Automatically the brain bestows on the animate object some properties common to things that are alive. Then the object may be further categorized as an animal or even more specifically as a human or a predator, and even more properties are inferred. Barrett and Boyer summarize the features of these inference systems for us,7 and some of their properties have specific bearing on our topic.

1. Each of the different domains deals with a different type of problem and has specific ways of handling information. Each has a specific input format, a specific way it infers information, and a specific output form. For instance, most psychologists will agree that humans have a special system to recognize human faces. The input format for face recognition is concerned with the overall arrangement and the relations of the parts to each other, rather than with specific parts. The input pattern that your brain looks for automatically consists of two brightly contrasted points (eyes) and a central opening (mouth) below. When the input format is not this way, for instance if you turn a picture upside down, faces are harder to recognize.

2. Just because there is a specialized domain for a specific problem, the domain does not necessarily correspond to reality. We see faces as the important aspect of a person because we have a system that pays particular attention to them. But are they really important? Not all animals have this system and see human faces as important. Neither now nor in the evolutionary environment would an impala need to know whether it was Pierre, Chuck, or Vinnie who was chasing it, or even that they are human; all it needs to know is that a predator is chasing it.
The reality may be that there are fourteen different predator species that it needs to recognize, but it may recognize them all as only one species: an animal with eyes facing forward that runs. We could have evolved with a foot-recognition system instead, and it would be feet that we would gaze at lovingly and think were important. All you would have to do to be incognito would be to put on a pair of boots. The system does not necessarily recognize objects as wholes, but notices aspects of the object. For the face, there is a system to identify the person and a different system to identify their mood.
One problem is that if there is an ambiguous aspect of an object, the system may infer the wrong information. There are two darkly contrasting points and a central opening over there in the dark. “Yikes! There is someone in those bushes!” No, it turns out to be a hubcap with holes in it. Another problem is that the system may infer scientifically incorrect information, although it is information that is mostly correct and has worked well enough so that it has been selected for. The system that identifies plants assumes that plants don’t move of their own volition. Some plants do, but they are rare, so it doesn’t affect the accuracy much. It is important for us to note, however, that the human brain does not divide living and nonliving things up the same way that a scientist would, based on verifiable information.

3. It is through the process of evolutionary selection that the specific system has arisen, so we need to keep in mind what the original function of the design was, because…

4. We may use a domain in ways other than the one it was selected for. For instance, our ears have evolved because they captured sound waves, which improved hearing, but we now also hang glasses from them. Bipedal locomotion was selected for because it gave some survival advantage in finding food and shelter, but we also use it for salsa dancing. The proper evolutionary use of a domain may be quite different from its current use.

5. You (and every other animal) can learn and infer only what your brain is programmed to be able to do. We cannot learn to hear sound frequencies beyond the range of our hearing, because our systems are not programmed to be able to. We can learn to speak because we have a domain that is ready to learn language. We cannot consciously feel what our brains are doing when they are performing unconscious processes. We can see three dimensionally even though a two-dimensional pattern falls onto our retina, because we have a specialized visual system that fills in the visual blanks. So where animals are concerned, because we have a brain that is predisposed to species-specific taxonomy, we are able to use all the incoming information, such as shape, color, sounds, motion, and behavior, to infer similarities and differences.

6. Different domains learn things in different ways and have different developmental schedules, so optimal learning takes place at specific times in development. We have seen that there is an optimal time in development to learn language. We will be talking about our intuitive knowledge of physics. This develops earlier in babies than a fully developed intuitive psychology. It develops earlier than children can speak, so we have had to figure out how to find this out without resorting to language.

7. Genetic influence continues throughout the life of an organism. It doesn’t stop at birth, and there are specific pathways that development follows, which are genetically encoded. All children everywhere follow the same general developmental time schedule, though there can be individual differences. Even if you are really really, really smart, you still don’t learn to speak when you are three months old.

8. In order to develop these systems, a normal environment is needed to input the proper stimuli. In order to learn to speak, one needs to hear others speak, just as songbirds need to hear other songbirds sing before they can sing. In order to develop proper vision, one needs visual input and can’t be raised in the dark.

9. These systems that infer information for survival and fitness are most likely interconnected, so that more than one area of the brain is activated when they are employed.

Children from the age of three already infer that something that falls into the animate category has some essence that makes it what it is and does not change. When shown pictures of slowly transforming animals, such as a porcupine turning into a cactus, children will put their foot down at some point and tell you that it doesn’t matter what you do to it, it is still a porcupine. Susan Gelman15 and her students at the University of Michigan wondered if this is information that has been explained to them or if it is innate knowledge. They analyzed thousands of mother-child conversations about “animals” and “things,” conversations from several families that occurred over a period of several months. The insides of something, what made it tick, and its origins were rarely discussed, and if they were, the discussion usually involved things, not animals. Children are born believing in essences; it is not something they are taught. Nine-month-old babies also already believe in the essence of objects. If you present them with a small box that makes a sound when you touch it in a particular place, they expect all identical small boxes to possess the same quality. Three-year-old children will go a step further and infer that similar boxes have the same quality, even if they are not exactly the same.

Using these examples, Yale psychologist Paul Bloom, in his fascinating book Descartes’ Baby,16 tells us that children are natural believers in essentialism, the philosophical theory that a thing perceivable to the senses can have an embodied unobservable essence that is real. Bloom says essentialism in some form shows up in all cultures. This essence may take the form of DNA or a gift from God or your astrological sign or, as a Yoruba farmer will tell you, a “structure from heaven.” Bloom considers essentialism an adaptive way to think about the natural world. Biologically, animals are similar because of a shared evolutionary history. Although appearance has some relevance as to what group an animal is in, more reliable indicators are deeper. So this inference that animals have an essence that does not change, even when the physical features do, has validity and ratifies the innate dualism in children. The converter is at work.

Do other animals have a concept of essences? Jennifer Vonk and Daniel Povinelli don’t think so.17 After reviewing studies that have been done to tease out how animals categorize entities as either same or different, they have concluded that all findings so far can be explained by other animals’ using solely perceivable traits: appearance, behavioral patterns, odor, sound, and touch. For other animals, appearance is reality.

When you start trying to design experiments to separate perceivable relationships from unobservable relationships, you realize it is quite difficult, and you begin to understand that perceivable relationships will do quite well most of the time. In fact, they have proven to be very difficult to distinguish, and Vonk and Povinelli don’t think there is any good evidence that animals use more than perceivable characteristics. Their interpretation of the current findings is that pigeons and monkeys can perceive first-order relationships: They have a concept that two things that share common perceptual characteristics are the same. The researchers emphasize that the key word here is perceive, just as the Kangaroo Island wallabies perceived that the stuffed fox and cat were things they should be concerned about, because they shared perceptual features that put them in the to-be-avoided class. Would a wallaby have been fooled by sheep’s clothing? If all other perceivable clues were eliminated, such as odor, type of movement and behavior, and sound, and the fox kept his mouth shut and wore a mask, probably. And you might have been, too. But foxes don’t actually dress up in sheep’s clothing.

Appearances are good enough in the animal world unless the animals are dealing with humans. Let’s just throw in an anecdotal tale. Apparently mountain lions can be fooled! This from the California Department of Fish and Game Web site: “One incident involved a turkey hunter who was camouflaged and calling for turkeys when a mountain lion approached from behind. Immediately after the mountain lion confronted the hunter and realized that the hunter was not a turkey, the lion ran away. This is not judged to be an attack on a human. Every indication suggests that if the hunter had not been camouflaged and calling like a turkey, the mountain lion would have avoided him.”

Understanding second-order relations means that one understands that the relationship between these two items is the same as the relationship between those two items. Remember your verbal SATs? The analogy section? How well did you do with those? There is evidence that the great apes are capable of understanding some second-order relationships, but as yet there is no evidence that they can do so with information other than what is observable. Even in chimpanzee social relationships, such as dominance or emotional relationships like love or attachment, all can be explained by observable phenomena. If this doesn’t make sense to you, then explain how you know that someone loves you. “Well, he kisses me good-bye every morning.” Perceivable. “He calls me from work every day.” Perceivable. “She goes out of her way to do nice things for me.” Ah, perceivable. “She tells me she loves me.” Ah, that would be a ditto. Vonk and Povinelli point out that we may define love as feelings, an inward manifestation, but we describe its visible outward manifestations. You can’t actually feel another’s feelings, you infer them through perception, the observation of their actions and facial expressions. We advise our friends in the throes of infatuation, “Actions speak louder than words.” Your dog is loyal to the audible, visible, sniffable you, not the essence of you.


We also have an intuitive knowledge of physics, although your physics grades may not reflect it. Remember that the intuitive systems make us pay special attention to things that have been helpful in survival. To survive, you didn’t really need an intuitive system to help you understand quantum mechanics or the fact that the earth is however many billions of years old. It is not so easy to grasp these concepts, and some of us never do. However, when you knocked the knife off the table at breakfast, there were many aspects of physics you did unconsciously take into account. You knew it would fall to the floor. You knew it would still be there when you leaned over to pick it up. You knew it would be directly beneath you and didn’t fly into the living room. You knew it would still be a knife, that it had not morphed into a spoon or a lump of metal. You also knew it wouldn’t pass through the solid floor and end up under the house. Was all this knowledge learned through experience, or was it innate? Just as you understand these things, very young infants already understand these same aspects of the physical world.

How do we know? What if, instead of falling onto the floor, the knife had flown up to the ceiling? You would have been surprised. In fact, you would have stared up at that knife. Babies will do the same thing if they see something unexpected. They will stare.

Babies expect objects to conform to a set of rules, and when they don’t, they will stare at them. By five months of age, babies expect objects to be permanent. They don’t just disappear when put out of sight.18 In a number of experiments, Elizabeth Spelke at Harvard and Renée Baillargeon at the University of Illinois have studied for years what babies know about physics. They have shown that infants expect objects to be cohesive and to stay in one piece rather than spontaneously break apart if you pull on them. They also expect them to keep the same shape if they pass behind a screen and reemerge. For example, a ball shouldn’t turn into a cupcake. They expect things to move along continuous paths and not to travel across gaps in space. And they make assumptions about partially hidden shapes. They also expect an object not to move on its own without something touching it, and to be solid and not to pass through another object.19, 20 How do we know this isn’t learned knowledge? Because babies everywhere know the same stuff at the same age no matter what they have been exposed to.

Babies do not understand everything about physical objects, however. It takes them a while to understand the full implications of gravity. They understand that an object can’t just be suspended in midair, but not until they are a year old do they understand that an object must have support under its center of gravity or it will fall.21 This is why the sippy cup was invented. Of course not all physical knowledge is innate. There is plenty that needs to be learned, and some adults never learn some of it, hence your physics grade. To what extent other animals share our intuitive physics is not yet known. As Marc Hauser says in his book Wild Minds, it seems inconceivable animals would not understand object permanence. There would be no prey animals left if they didn’t understand that the predator that walked behind the bush is still there and didn’t disappear into thin air. However, there are some major differences in what we understand about physics and what other animals understand, and in how we use the information.

Povinelli and Vonk,17 having reviewed what is known about the physical knowledge of nonhuman primates, suggest that although it is clear they can reason from observed events to resulting causes, they do not appreciate the causal forces that underlie their observations. For instance, if they understood the cause of gravity, instead of knowing only by observation that fruit will fall to the ground, then they should also understand that if they were reaching for something and dragged it across an open void, then it too would fall into the void. They can’t figure this out. They don’t understand force. They understand that objects touch each other, which is observable, but they don’t get the idea that in order for one object to move another, some force has to be transferred: A cup needs to be sitting on top of a tablecloth when the cloth is pulled in order for the cup to move; it can’t just be touching the tablecloth. They just don’t get it. This contrasts with two- and three-year-olds, who do get it. Children will prioritize the cause of simple events by an unobservable feature (the transfer of force) over an observable feature (for instance, proximity).22 It has been proposed23, 24, 25 that humans are unique in their ability to reason about causal forces. Sure, some animals understand that an apple will fall off a tree, but humans are the only animal that can reason about the invisible cause—gravity—and how it works. Not that we all do.

Our object taxonomy for physical objects, man-made artifacts in particular, works differently than our biological taxonomy. Artifacts are classified mostly by function or intentional function,26 and are not hierarchically classified like plants and animals. When something is classified as a man-made artifact, different inferences are made about it than about a living thing. It gets a different profile. In fact the identification and profiling systems can get even more specific. Motor regions of the brain activate when tools are the objects27 and when the artifact is manipulable,28 but not with man-made objects in general. We infer all the above physical properties, but not the properties we infer for living things, except in special circumstances.

After the detective device has answered What or who is that? or Who or what did that? the information is sent to the describers, which infer all the properties of what has been identified. So back at breakfast when you looked out the window and saw the flitting, softball-size what-or-who-is-that, the object detective identified it as a physical object with a definite border rather than something formless, and, wait a minute…the object has initiated its own motion, a biological-type motion, so the detective device signals, “It’s alive!” The animal identifier chimes in with “Ah, it’s a bird.” Once it has been identified, the animal describer infers that it has all the properties of its class: It would have all the physical properties of an object in space, plus those of an animal and those of a bird. This all happens automatically, even if you have never seen that specific animal before. If the detective device says it’s a whoas opposed to a what problem, and identifies the quarry, then the agent describer or TOM is engaged. This is another area of intuitive knowledge, known as intuitive psychology, which also contributes to our nonreflective beliefs.


We use our theory-of-mind system (our intuitive understanding that others have invisible states—beliefs, desires, intentions, and goals—and that these can cause behaviors and events) to ascribe these same characteristics not only to other humans but also to the animate category in general, even though other animates do not possess it to the same degree humans do. (Sometimes it can also get sloppily slapped onto objects.) This is why it is so easy to think of our pets and other animals as having thoughts and beliefs like our own and why anthropomorphism is so easy to resort to. This is also why it can be so hard for humans to accept that their psychology is unique. We are wired to think otherwise. We are wired to think animate objects have TOM. We think other animals, especially ones most similar to us, think as we do. Our intuitive psychology does not limit the extent of TOM in other animals. In fact, when presented with films of geometric shapes moving in ways that suggest intention or goal-directed behavior (moving in ways that an animal would move), people will even attribute desires and intentions to geometric figures.29 Yes, other animals have desires and goals, but they are shaped by a body and a brain that has answered survival and fitness problems with different solutions. We are not all hooked up the same.

Anthropomorphism is not the only common type of thinking that has roots in TOM. If your biology teacher chastised you for that, perhaps you also had a big red mark for teleological thinking—explaining facts of nature as a result of intelligent design or purpose. You were in trouble in biology class if you said giraffes have a long neck so they can eat the leaves of tall trees, that is, their neck was designed to reach the high leaves.* However, this may actually be a default mode of thinking that is fully developed between ages four and five.

Whereas both adults and children will resort to teleological explanations for biological processes, such as that lungs are for breathing, children resort to teleological thinking for more diverse situations than adults do. They have a bias to treat objects and behaviors of all kinds as existing for a designed purpose.30, 31, 32 They will extend this reasoning to natural objects and will say clouds are there to rain, mountains are there so you can go for a hike, and tigers exist for zoos.

The origins of teleological thinking are still being hashed out. There are three proposals. Either it is innate, or it comes from understanding that man-made objects are designed for a purpose,33 or it derives from the understanding of rational action that babies exhibit and thus may be a precursor of TOM.34

Teleological thinking explains a phenomenon by invoking an intended design. However, the fact we are even trying to explain an effect having been caused by something is also most probably a unique ability. Other animals do understand that certain things are linked to other things in a causal manner. Your dog may learn that chewing your Gucci shoes causes the effect of getting a swat, or yelled at, and he may learn that chewing his bone does not cause that effect. However, as we discussed with intuitive physics, there is no clear evidence that other animals form concepts about imperceptible things. Your dog doesn’t understand that the unperceivable cause of the swat was the cost of the shoes or your notions of dog obedience. Vonk and Povinelli17 have proposed that the human ability to reason about unobservable entities and processes goes beyond causal physical forces and includes the psychological realm. This reasoning about unobservables can then be used to predict and explain events or psychological states. Thus, once full-blown TOM developed, it greatly enhanced the ability to predict behavior beyond just observable phenomena. One could predict the behavior of another animal by inferring its psychological state.

While other animals and humans use observables to predict, it may be that humans alone also try to explain.35 Only one experiment so far has addressed this notion. Chimps and preschool children were given some blocks that they were to stand on a platform covered with an irregular mat. In the first experiment, among the blocks was one sham block that had had its ends beveled so it could not stand up. In the second experiment, the blocks were visibly identical (all L-shaped) and all of the same weight, but the sham block had been weighted so that it could not stand up on its long axis. In the first experiment, both the children and the chimps examined the visibly different block. However, in the second experiment, in which the difference between the blocks was not visibly perceptible, 61 percent of the children investigated the sham block to figure out why it couldn’t stand up, but none of the chimps did.36

Sometimes our predilection for explaining the cause of things or behaviors with teleological thinking runs amuck. One of the reasons is that the agency-detection device is rather zealous. Barrett calls it hyperactive. It likes to drum up business, so it finds animate suspects even when there are none. When you hear a sound in the middle of the night, the question that first comes to mind is Who is that? rather than What is that? When you see a wispy something moving in the dark, Who is that? comes to mind because the detective device is not modern and up-to-date. The detective device was forged many thousands of years ago before there were inanimate objects that could move or make noise on their own. To first consider a potential danger as animate is adaptive. It worked most of the time. Those who did it survived and passed their genes to us.* Sometimes blunders are made, but they usually aren’t much of a problem. We realize the wispy something is a towel someone left hanging in the tree, and the noise is the house creaking as the temperature cools.

The hyperactive detective device, combined with our need to explain and teleological thinking, is the basis of creationism. To explain why we exist, the hyperactive detection device says there must be a Who involved. Teleological reasoning says there must be an intentional design. The cause must be the desires and intentions and behavior of the Who. Thus we were designed by a Who.

All of this is reminiscent of what the left-brain interpreter would do, which it has been demonstrated to do in other settings. In the next chapter, we will see it become hyperactive in cases of neurologic disease when it produces seemingly bizarre stories of causality, given the bad information it receives. The interpreter and the theory-of-mind modules seem to be close cousins.

Povinelli has suggested that TOM was “grafted” onto already existing cognitive systems for reasoning about perceivable behavior, thus allowing humans to reinterpret already existing, complicated social behavior with the additional ability to think about mental states.37 TOM did not replace already existing systems and is not necessarily always resorted to. The key point to this idea is that it expects humans and their nearest living relatives, the great apes, especially chimps, to behave similarly, because being able to predict behavior by observation had evolved before TOM. These systems for reasoning about behavior were already highly sophisticated and complex, and they became closely connected to the TOM system. However, just because other animals may have some of the same behaviors that we do, inferring from this that they have the same cognitive system may not be correct. Also, just because we have a system to seek out cause from unobservables does not mean we use it all the time. It is unknown when our concepts about unobservables are activated and to what extent they inform human behavior. It is possible that in many situations they are not activated at all. It is also evident that not everyone possesses the ability to use TOM to the same extent.

We will see in a moment that oftentimes we can come to the same conclusions whether we use our TOM or not.


More-specialized domains come into play in specific circumstances when the profiler doesn’t provide enough information, and many of these are involved in social interactions. Some of these systems also act like statisticians and predict human behavior or guide it under specific circumstances. We have already talked about how some of these systems are active for social exchange, precautionary exchange, and the many moral intuitions that we have. There are probably umpteen others, including one for math. Babies expect there to be two Mickeys behind a screen when they see one go behind it, and then one more.38 Plus we have memory and our past experience to draw on. So now there is quite a bit of information available.

So at breakfast you gaze out the window and see an object move toward you and then bend and straighten and move away from you. Your detective device has identified it as human, and even more specifically identified it as your neighbor Luigi. Your animal describer tells you all Luigi’s properties, including TOM. Could you and your dog predict Luigi’s behavior correctly without taking TOM into account? If Luigi has been your neighbor for a few months, then when you see him, you also remember that he came out yesterday morning and picked up the paper, and the morning before that he did the same thing. You could actually predict his behavior without even using your TOM. Your dog also has seen Luigi come out each morning and bend over and pick up the paper. Everything looks the same as yesterday; your dog predicts the same behavior. Now try the same scenario using your TOM. Both you and your dog see the newspaper and see the front door open with Luigi on the threshold. Now you have an edge on your dog. Your profiler has inferred that Luigi has TOM. You know he has desires, and you can use your intuitive psychology to predict ( just as if you were he) that one of those desires is to read the paper. Yep, there he goes. But that was no different from what you and your dog predicted without TOM. TOM is an embellishment that is called in especially in human social interactions, for which we sometimes use it to predict behavior. But its most important function allows you to understand that that hunk of cells over there has unobservable beliefs and desires, just as you do, which are motivating it. The information has been automatically converted to give another status or state to Luigi.

Intuitive psychology is a separate domain from intuitive biology and physics. This is important, because a desire or a belief doesn’t get tagged with physical properties, such as “has gravity” or “is solid,” or with biological properties, such as “eats” or “has sex” or, most important, “dies.” When Luigi comes out for his paper, do you believe his desire is purple? Do you believe that it will fall out of his head when he leans over to pick up the paper? Do you believe that his desire is going to eat breakfast? No. You don’t believe any of that. Do you believe that his desire can pass through walls? Do you believe his desire can disappear into thin air? Do you believe that his desire can die? Does that mean it stops breathing? Now your responses may not be so quick. Your intuitive mechanisms are getting all flustered.


The divide between the domains is apparent in autism, in which the lack of social understanding is a prominent feature, but it can also be associated with impairments in imagination and communication. Children with autism rarely engage in imaginative playing, and many do not speak at all. It is thought that individuals with autism suffer from “mind-blindness.” They are blind to the understanding that other individuals have desires, beliefs, goals, and intentions—that they have a mind. Autistic children do not possess a theory of mind; they lack an intuitive psychology. This lack of intuitive psychology is what makes social interactions so difficult. Instead of automatically knowing that when you smile you are happy, or that your furrowed brow indicates displeasure, they have to learn and memorize what these expressions indicate and consciously apply the lesson each time they see one. This lack of understanding also explains other characteristics of children with autism, such as not pointing things out or looking to their parents for guidance. If they don’t understand that others have a mind, then there is no reason to show them something or look to them for advice. You don’t point the dust out to your broom or ask your dictionary for advice.

When shown the films mentioned above, of the geometric figures exhibiting intentional action, autistic subjects merely give a physical description and do not ascribe intentions to them. The researchers give an example that is so demonstrative of the difference, I will repeat it here.

The first is a response from a normally developing adolescent describing the forms in the film: “What happened was that the larger triangle—which was like a bigger kid or a bully—and he had isolated himself from everything else until two new kids come along and the little one was a bit more shy, scared, and the smaller triangle more like stood up for himself and protected the little one. The big triangle got jealous of them, came out, and started to pick on the smaller triangle. The little triangle got upset and said like, ‘What’s up? Why are you doing this?’”

Contrast that response with the following from an autistic adolescent: “The big triangle went into the rectangle. There were a small triangle and a circle. The big triangle went out. The shapes bounce off each other. The small circle went inside the rectangle. The big triangle was in the box with the circle. The small triangle and the circle went around each other a few times. They were kind of oscillating around each other, maybe because of a magnetic field. After that, they go off the screen. The big triangle turned like a star—like a Star of David—and broke the rectangle.”39

Instead of bestowing social relationships on the geometric figures in the film, the autistic children described solely physical relationships. Multiple MRI studies have been done in order to understand how the brain is different in autistic individuals. Of importance to our discussion is that when autistic individuals looked at faces, the activity was significantly lower down in a region of the brain called the fusiform gyrus, widely accepted to be specialized for the perception of faces.40, 41 The autistic groups showed greater activation in adjacent regions of the temporal cortex that are usually associated with objects. Indeed autistic children often treat other people as objects. Other people can be terrifying to autistic individuals because they do not act like objects; they move and do things that are unpredictable according to their nonreflective intuitive beliefs of how objects should act.


Paul Bloom, who contends people are natural-born dualists, states that in individuals who do not have autism, this processing of object understanding separate from social and psychological understanding is what gives rise to our “duality of experience.” Objects, the material, physical things of the world, are treated separately and differently from the nonvisible psychological states of goals, beliefs, intentions, and desires. Different inferences are made. Part of that physical world is what you can look down and see: your body, that physical biological object that eats and sleeps and walks and has sex and dies. But the psychological part is not visible; it does not have an obvious physical substance and is subject to different processing and inferences. It is not a physical biological object subject to that same array of inferences. You have a nonreflective intuitive belief that the body and its conscious essence are separate.

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 assign 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 gods or God. It would follow from Povinelli’s reasoning, then, if animals cannot form concepts of imperceptible entities 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?


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 associated with the dead is visual indication of dualism at work. Although Neanderthals occasionally buried their dead, Cro-Magnons (the first anatomically modern Homo 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 assumed to be useful.42 A belief in an afterlife assumes 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 carcasses or skeletons…when they come upon an elephant carcass 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 Sussex, 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.


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 circumstances. 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 analytical 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 assign 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 voilà: a physical biological body and an unobservable psychological essence, two things in one. As Descartes would have said, “Pas de probléme!


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 unobservable 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 analytical 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.