Human. Part 7

WHAT ABOUT MUSIC?.

Marc Hauser at Harvard and Josh McDermott at MIT, among many others, cla.s.sify music as a uniquely human endeavor.64 Only humans compose music, learn to play musical instruments, and then play them together in cooperative (usually) ensembles, bands, and orchestras. None of the other great apes create music or sing. Too bad, or Greystoke: the Legend of Tarzan could have been a musical. That means that our common ancestor didn't sing.

What about birdcalls? They certainly sound like music. Hauser and McDermott say birdsong is a different kettle of fish. Birds sing only in certain contexts: mating and territorial defense. Singing is done primarily by males, and its sole function is for communication. This also seems to be true of whales. It is not done for pure enjoyment. Apparently, birds don't sing alone in the shower. And birds don't change their scales or the key in which they sing. There are no telephone-line quartets tweeting harmonies in the bird world. You see a canyon wren; you hear the descending call of a canyon wren. A canyon wren doesn't all of a sudden change its song from the key of C to A-sharp minor and add a little rhumba beat at the end.

Songbirds are a bit more variable. Some songbird species can mimic and learn the calls of other species and may splice parts of one call with another, although they prefer the calls of their own species.65 There are, however, limitations of various kinds with different species of birds, and no bird species is equally able to acquire new songs at any time of its life. There are sensitive periods when they are able to learn songs more readily.

It is interesting to consider, however, that just as birds have constraints on their auditory systems and what and when they sing, and on when and how they learn and remember their songs, so we too have constraints on our auditory system, on what we consider pleasing music, and on when and how we learn to play and remember it-and we may share some of these constraints with other animals. Comparative studies of these constraints are just beginning.

However, there is something unique going on in our brains that has picked up the tempo, so to speak. We compose new music, play it, and listen to it not just to attract chicks, pay the bills, or impress our friends. We can pick up the fiddle and fire off a tune when we are alone, just for the sheer pleasure of it. Inventing and playing music uses all our cognitive machinery, as anyone knows who has learned to play. It is not an easy a.s.signment. Perception, learning and memory, attention, motor action, emotion, abstraction, and theory of mind are all harnessed into action. Music is another one of those human universals.66, 67, 68 Every culture in the present and in the past has had some form of music. People like to boogie. Perhaps the oldest musical instrument that has been found is a fragment of a bone flute made from the femur of the now-extinct European bear. It was excavated in 1995 by paleontologist Ivan Turk in a Neanderthal burial mound in Divje Babe, Slovenia. Whether this is truly a flute is controversial. It has been determined to be around 50,000 years old. In all likelihood, there were probably drums from earlier dates that were made of materials that have not been preserved.69 To the consternation of those who attribute the tonal octave to relatively recent western music, still playable 9,000-year-old flutes have been found in Jiahu, China. These flutes sound tonal scales, one of them an octave.70 We Are All Musicians.

The adaptive theories of music have explanations similar to the ones we heard for visual art. Steven Pinker ruffled feathers, as only he can do, a few years ago when he wrote that he suspected that music was auditory cheesecake and that perhaps it had no adaptive purpose but was a by-product of other functions.2 Cheesecake? Many disagree with his conclusion and think music serves an adaptive function. Like the other arts, perhaps it has been s.e.xually selected to attract mates (the arguably adaptable Mick Jagger effect) and to signal mate quality, as the s.e.xual-selection advocate, Geoffrey Miller, suggests.18 Or maybe it acted as a social bonding system, much like language, that synchronized mood and perhaps prepared the group to act in unison, thus binding coalitions and groups.69, 71 But if these were true, why would anyone play music when they were alone? Research on this topic is in its infancy, and there is no widely accepted concept.

Once again, Darwin had something to say. He suspected that music may originally have been adaptive as a form of communication, a protolanguage, that later was replaced by language. If that was true, music now is a "fossil" of a former adaptation. Tec.u.mseh Fitch, a linguist from University of St. Andrews, Scotland, following Darwin's reasoning, suggests that that would put music in a subtle category of former adaptations having a biologically grounded cognitive domain that are currently being used not as originally selected for but not in a completely different manner either.72 Speech shares many features with music and also with primate vocalizations, such as pitch, timbre, rhythm, and changes in volume and frequency. These are all things that we are good at identifying even without musical training. You may think that you don't know anything about these aspects of music, but if I ask you to sing your favorite song, you will be able to do it pretty well. In fact, when Dan Levitin, a former rock-and-roll music producer turned neuroscientist and now a professor at McGill University, asked students to sing their favorite song, they easily reproduced the pitch and tempo of songs.73, 74 If I play a note on a piano and the same note on a violin, you will be able to tell which is which. That means that you can recognize the timbre of the note. In fact, you knew all that stuff when you were a baby.

Sandra Trehub, who studies the developmental origins of music in infants at the University of Toronto, summarizes findings that babies from at least six months old have relative pitch: They can recognize a melody even if it is played in a different key.75 The only time any other mammal has demonstrated relative pitch was in one experiment done on only two rhesus monkeys.76 But they weren't as good as babies. They could recognize melodies played an octave apart as being the same, but not if they were played in different keys or in an atonal scale. Babies also recognize melodies if they are played at different tempos. This is not because they can't tell the difference between them; they are very discriminating. They can differentiate between semitones in a scale, changes in the timbre, tempo, meter, and grouping of notes, and duration. They can tell consonance from dissonance from the age of two months, and they prefer consonance and harmonic music to dissonant.* This does not appear to be culturally engendered, but that has been difficult to prove. Babies who have never heard any form of music are rare. Even fetuses respond to music with changes of heart rate.77 Music has proven to be a difficult research topic because it has all those components I have already mentioned: pitch, timbre, meter, rhythm, harmony, melody, loudness, and tempo. These are part of musical syntax and are also part of verbal syntax.

Have you ever tried to speak a foreign language? Trying to be social with a bus driver in Italy on a rainy day, I asked, "Dov'e il sole?" a short and simple sentence. He looked at me puzzled. I thought to myself, I know I have the words right. He must just be perverse in not recognizing them. But then I thought about all the times someone has said something to me in English with a foreign cadence and I haven't been able to understand him or her. The words were correct, but the emphasis was on the wrong syllables, or the wrong word in the sentence was emphasized, or the words ran together incorrectly. I realized I had p.r.o.nounced sole with the accent on the second syllable, as if I were saying soleil in French, rather than on the first syllable. Think of the sentence "Sunday was a lovely day for sailing," but say it as if it were written "Sunday was, a love lyday forsai ling." Your companion would look puzzled too. Prosody is the musical cues of language: melody, meter, rhythm, and timbre. Prosody helps delineate the word and phrase boundaries. Some languages are very melodic, like Italian. Some languages, such as Chinese, are tonal, which means that the same word means different things just by varying the pitch. Some researchers think that the brain, at least at an early age, treats language as a special case of music.78 We know that music can convey emotion, just as some animal calls can. However, music can convey meaning other than emotion.79 It can actually prime you for the recognition of words. There is a way to measure with an EEG how semantically similar the brain recognizes words to be. Just as when a person is presented with a sentence such as "The sky is blue," and then recognizes the word color afterward as being more closely related than the word billboard, a certain pa.s.sage of music will prime you to afterward recognize certain words as being more semantically related to the music than others. For example, after hearing musical notes that sound like a clap of thunder, you would find the word thunder more related than the word pencil. In fact, when words were presented that the composer, by his own admission, was trying to convey, such as st.i.tch (as in sewing), they were actually the words that the listener found to be related. Many musical sounds are universally recognized to convey certain meanings. Like language, music has phrase structure and recursion. You can create an endless variety of musical phrases by putting together different notes and groups of notes. Just as humans are easily able to a.s.semble phrases into an infinite number of meaningful sentences, we are able to structure and process multiple musical phrases. It appears that humans are the only animals with the ability to do this both verbally and musically.80 Music and language also share some of the same neural areas. Dan Levitin, working with Vinod Menon at Stanford, has found two regions of the frontal lobe* that are closely a.s.sociated with the processing of language and are also active when listening to cla.s.sical music with no accompanying song. They speculate that this area is used to process stimuli that evolve over time, not only words but musical notes.81 Other researchers have found that if you hear a chord that is not "right," something your brain does not expect to hear, an area in your right frontal cortex is activated, as well as the area that corresponds to that area in the left frontal cortex, which is thought of as the language network.82, 83 This corresponding area in the left hemisphere is also activated when you hear a phrase structure that is wrong, such as "dog walked park he." These areas appear to be sensitive to violations in expected structure, and in the left hemisphere there is an overlap between music and language processing.

Just as we like to hear a good story or look at a starry sky, we also play music because we like to hear it. What do we like to hear? As I mentioned before, we like consonance, and, though you might freak out when I tell you this, there is another fractal thing going on with music. Scaling noise is a type of sound whose quality is unaffected by how fast it is played. White noise is the simplest example. It is monotonous at any play speed. It is at one end of the spectrum of scaling noise; it is made up of completely random frequencies. At the other end is noise that is completely predictable, like a dripping faucet. In the middle is noise with what is known as 1/f spectra; it is partially random and partially predictable. The amplitude and pitch fluctuations of natural sounds, such as running water, rain, and wind, often exhibit 1/f spectra.84, 85 In other words, large, abrupt changes in pitch or loudness occur less frequently in nature than gentle, gradual fluctuations. Most music falls into the same range of 1/f spectra.84 Furthermore, human listeners reportedly prefer 1/f-spectra melodies to melodies with faster or slower changes in pitch and loudness. Many auditory cortical neurons are tuned to the dynamical properties of the natural acoustic environment,86 which could explain why stimuli with naturalistic amplitude spectra are processed dramatically better than other stimuli.87 Back to the old fluency in processing theory: We process it more easily, so we end up liking it. It's pretty interesting that both our auditory system and our visual system have this built-in preference for natural landscapes and sounds. It's also interesting that one of the dictionary definitions for art was the human effort to imitate nature.

So we are listening to some music, and it puts us in a good mood. At least the Stones do. But sometimes it makes us sad. And what about that music in Jaws? That made us tense. Music can actually elicit emotions.88 In fact, you can get so emotional that you get a physiologic reaction, such as the chill down your spine and changes in your heart rate.89 But even more interesting, you can block that reaction by getting injected with the drug nalaxone,90 which blocks the binding of opioid receptors. It is well established the body produces a natural high by releasing its own opioid when we listen to music that we like. Nalaxone, the same drug that is given to someone who has overdosed on heroin and makes it to the ER on time, will also block the binding of the natural opiates that your body produces. The first hints of what was going on in the brain came from scans done on musicians91 as they listened to music that gave them the "chills." The same brain structures* were activated that are active in response to other euphoria-inducing activities, such as eating food (fats and sugars), s.e.x, and downing so-called recreational drugs.

Menon and Levitin were able to do more-specific scans with nonmusicians and found that the hypothalamus was activated (which modulates heart rate, respiration, and the "chills"), as were specific neural areas that are crucial for reward processing. They also found evidence for a correlation between dopamine release and the response to pleasant music. This is a big finding. Dopamine is known to regulate opioid transmission, and increased levels are theorized to cause positive affect.92 This release of dopamine also happens as a reward when one drinks water and eats food, and also is the reinforcing effect of addictive drugs. Is music rewarded because it too is a survival-related stimulus? Or is it auditory cheesecake, just another recreational drug? This question has not yet been answered, but one thing is for sure: Music does increase positive affect, just as some visual stimuli do.

Increasing positive affect is a good thing, whether it is from auditory, visual, or any other sensory experience. Being in a good mood increases cognitive flexibility and facilitates creative problem solving in many different settings. It has been shown to increase verbal fluency. People with a positive affect widen category groups by finding more similarities between objects, people, or social groups, enabling a socially distinct out-group to be placed into a broader mutual in-group-"Well, I know he is a Lakers fan, but at least he loves to fis.h.!.+" This results in less conflict. Having a positive affect makes tasks seem more rich and interesting. Interesting tasks make work more rewarding and induce people to find improved outcomes in problem solving. A good mood stimulates you to seek variety in safe pursuits, making you more inventive on dates. It just makes you a more pleasant and less rigid person to be around. This in itself would have adaptive potential.

Does Music Affect Our Thinking Abilities?

Spatial abilities are used to create, think of, remember, and change visual images in one's mind. For instance, looking at a two-dimensional map and being able to visualize its information in three dimensions to find one's way around in a city uses spatial ability. A few years ago, there was a suggestion that listening to certain cla.s.sical music would increase your spatial abilities.93 It became dubbed the Mozart effect. However, it proved difficult to confirm, and later studies revealed that it wasn't listening to cla.s.sical music or Mozart per se that made you smarter, but rather listening to music you prefer puts you in a better mood. When you are in a good mood, you are aroused, and this can lead to enhanced performance on a variety of tests of cognitive ability. Arousal stimuli aren't limited to music. One can be aroused by other preferred stimuli, such as a licking a glob of Nutella off your finger, or drinking a cup of coffee.94 Moreover, listening to music and actually taking music lessons are two different things in terms of their effect on the brain. Glenn Sch.e.l.lenberg, at the University of Toronto, has found in a randomly a.s.signed group of six-year-old children who received keyboard lessons, voice lessons, drama lessons, or no lessons that music lessons in childhood are a.s.sociated with small but long-lasting increases in IQ. (He incidentally found that drama lessons enhance social behavior but not IQ.) This increase was not affected by family income or parents' education, nor was it seen with other types of extracurricular studies. Learning music made you a little bit smarter. You can safely bet that these findings have sparked a great deal of interest. Proof of training in one field that generalizes to others has been hard to find.

In a detailed review of transfer effects, the ability to transfer knowledge gained in one context to another very similar context (near transfer) or dissimilar context (far transfer), Steve Ceci and colleagues95 found little evidence in a century's worth of previous studies for far transfer. Although there is little evidence for it, there is widespread belief that far transfer occurs, and this belief is central to Western concepts of education. Sch.e.l.lenberg points out that the goals of formal education are not just to build skills in reading, writing, and arithmetic but to develop the capacity for reasoning and critical thinking. His data that reveal music lessons increase IQ are a rare example of far transfer and might actually contribute to this process.96 Should we be putting band and music lessons back in school programs instead of tr.i.m.m.i.n.g them from the budgets? Do we know what music training does for the brain? We know a little but not exactly why it may increase IQ.

We know that musicians are using many skills at one time. They are seeing notes that are written and translating them to a special motor activity that has a time line. This involves both hands and in some cases the legs and feet, the mouth, and the lungs. Musicians use intonation and timing to imply emotion, they may transpose music to different keys, and they may improvise melodies and harmonies. Long pa.s.sages are committed to memory. Musicians often sing and play at the same time. Certain brain regions in musicians are bigger than in nonmusicians. It is not known if this is due to learning to play an instrument or if children who choose to learn an instrument have neural differences to begin with, but there is much evidence to suggest that learning causes these changes. There are also greater differences in the size of certain brain regions in those who began musical training at an earlier age. For instance, violin players have a larger region for the fingers of their left hand, the effect being smaller for the thumb, which is not used to an equal extent, and the overall increase is greater in violinists who started their training at a younger age.97 There are also corresponding size differences that correlate with the intensity of musical training throughout life. Professional musicians (keyboard players) have more gray matter volume in motor, auditory, and visual-spatial brain regions compared with amateur musicians and nonmusicians.98 These and other similar studies suggest that musical training can increase the size of certain neural structures. There are also suggestions that along with increases of IQ, it enhances verbal memory (you'll be able to remember jokes better), motor ability (you'll be a better dancer), visual-spatial abilities (you'll be better at juggling), the ability to copy geometric figures, and possibly mathematical ability.

Helen Neville's group at the University of Oregon is currently investigating the old chicken-and-egg question: Does music cause improvements in cognition, or are people with strong cognitive skills more likely to make the effort to learn music? Learning music requires focused attention, abstract and relational thinking, and what is known as executive control in the brain. Do the kids who study music already have these abilities, or does learning music develop them?

Neville and her colleagues are testing groups of children aged three to five recruited from a Head Start program. Their preliminary findings are that the children in each of the music/arts groups have more significant gains in language and preliterary skills than the gains made by children in the regular Head Start group. Children who received music/arts training also displayed significant gains in attention, visual-spatial skills, and numeracy. Children in the attention-training intervention displayed a similar pattern. If these results hold up, they suggest that training in music and the arts does improve language, attention, visual-spatial, and numeracy skills.99 Improving attention is also important. One aspect of attention, executive attention, concerns the mechanisms for self-regulation of cognition and emotion, such as concentration and impulse control. Being able to control emotional impulses can be lifesaving in panic situations.* How well this works is partly under genetic control, but Michael Posner and colleagues at the University of Oregon wondered if home and school environments could also exert an influence, as they do for other cognitive networks. This group has found that children aged four to six who partic.i.p.ated in attention-training tasks improved their emotional control.100 This improvement was equal to that garnered over the pa.s.sage of developmental time. They suggest that the immature system can be trained to function in a more mature way and also argue that the effect of attention training extends to more general skills, such as those measured by intelligence tests.

Currently a group from Boston101 is running a long-term study with the other chicken-and-egg problem of brain size. Do children who choose to partic.i.p.ate in musical training (piano or string instruments) show neural differences prior to training compared to a control group of children not seeking music lessons? They are also testing whether the music students have innately superior visual-spatial, verbal, or motor skills. Their third aim is to see if a test measuring musical perception before their training began correlates with any of the cognitive, motor, or neural outcomes a.s.sociated with music training. Their initial screening showed there was no difference in the groups of children before beginning musical training. After the first fourteen months of study, preliminary results in five- to seven-year-old children suggest that cognitive and brain effects from instrumental music training can be found. So far, these effects are small and are in areas that control fine motor skills and melodic discrimination.102 Another researcher, John Jonides, at the University of Michigan, has been testing musicians to see if they have better memories. It appears that they do, both long- and short-term memory in both visual and verbal tests. They are currently in the process of seeing if there is a close relations.h.i.+p between musical training, musical skill, and memory.103 For years, many people have thought musicians have greater mathematical skills. I would bet if you asked people on the street what cognitive advantage playing music gave to a person, this would be a very common answer. However, evidence for this is sketchy. Elizabeth Spelke is in the midst of testing mathematical abilities and music training in several different age groups. She has four different age groups: five to ten years, eight to thirteen, thirteen to eighteen, and adults. Preliminary results from those aged eight to thirteen show a significant advantage in geometric representation for the music-trained children; other results are pending.

CONCLUSION.

It seems that Tooby and Cosmides are right when they suggest that children should be immersed in an aesthetically pleasing environment. But children are not the only ones to benefit. Whether you are sitting in a mountain meadow or catching alpine glow along the Seine, looking at a Bonnard or your own latest handiwork, listening to Beethoven or Neil Young, watching Swan Lake or showing your kids how to tango, reading d.i.c.kens or telling your own tall tale, art can put a smile on your face. We may be smiling because our c.o.c.ky brain is pleased with itself, because it is fluently processing a stimulus, but you don't need to tell the artist that. The benefits to the individual and society from positive affect alone suggest that the world is a happier place if it is beautiful. I think the French figured this out a while back.

The creation of art is new to the world of animals. It is now being recognized that this uniquely human contribution is firmly based in our biology. We share some perceptual processing abilities with other animals, and therefore we may even share what we call aesthetic preferences. But something more is going on in the human brain-something that has allowed us to engage in pretense, as Alan Leslie suggests, some connectivity change that has allowed us to decouple the true from the imaginary and, as Tooby and Cosmides suggest, to use contingently true information. This unique ability has enabled us to be very flexible and adaptable to different environments, to break out of the rigid behavioral patterns that other animals are subject to. Our imaginative ability allowed one of us thousands of years ago to look at a wall of an empty cave in France and decide to spruce it up with a little fresco, another to tell the story of the odyssey of Ulysses, another to look at a chunk of marble and see David trapped inside, and another to look at a strip of bay-front property and envision the Sydney Opera House. What caused this connectivity change is unknown. Was it due to a change in the prefrontal cortex as a result of some small genetic mutation, or was it a more gradual process? No one knows. Did the increasing lateralization of brain function that we will read about in chapter 8 contribute to it? Maybe.

Chapter 7.

WE ALL ACT LIKE DUALISTS: THE CONVERTER FUNCTION.

The centermost processes of the brain with which consciousness is presumably a.s.sociated 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 n.o.bel 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 cla.s.sic mind/body duo. Philosophers have been discussing and arguing for literally thousands of years whether the mind and body are one ent.i.ty 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 s.h.i.+ft, 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 ch.o.r.e 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 cla.s.sify 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 pa.s.sed 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 gla.s.ses 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 cla.s.sified 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.

INTUITIVE BIOLOGY.

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 cla.s.sify 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 cla.s.sification 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 cla.s.sification 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 cla.s.ses 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 doc.u.ment 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.

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.

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 a.s.sumes 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.

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...

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 gla.s.ses 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.

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.

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.

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.

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.

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 a.n.a.lyzed 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 un.o.bservable 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 G.o.d 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 ent.i.ties 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 relations.h.i.+ps from un.o.bservable relations.h.i.+ps, you realize it is quite difficult, and you begin to understand that perceivable relations.h.i.+ps 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 relations.h.i.+ps: 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 cla.s.s. 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 relations.h.i.+p between these two items is the same as the relations.h.i.+p between those two items. Remember your verbal SATs? The a.n.a.logy section? How well did you do with those? There is evidence that the great apes are capable of understanding some second-order relations.h.i.+ps, but as yet there is no evidence that they can do so with information other than what is observable. Even in chimpanzee social relations.h.i.+ps, such as dominance or emotional relations.h.i.+ps 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.

INTUITIVE PHYSICS.

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 pa.s.s 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 Renee 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 pa.s.s 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 s.p.a.ce. And they make a.s.sumptions 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 pa.s.s 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 un.o.bservable 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 cla.s.sified mostly by function or intentional function,26 and are not hierarchically cla.s.sified like plants and animals. When something is cla.s.sified 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 circ.u.mstances.

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 cla.s.s: It would have all the physical properties of an object in s.p.a.ce, 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 who as 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.

INTUITIVE PSYCHOLOGY.

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 cla.s.s 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 no