The Making of the Mind: The Neuroscience of Human Nature (10 page)

Children can be thought of as developing a theory of mind as they come to understand others as intentional agents with minds of their own.
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That is to say, the child understands that other human beings have beliefs, desires, and thoughts about how to get what they want. Initially, the infant is like the solipsistic philosopher who argues that only he is exists as a conscious being, because the self has immediate access only to its own mind. As the infant matures and learns about the way animate agents move and act in the world to obtain things, she comes to see that others have minds as well. The social nature of human beings includes the capacity to engage in a form of mind reading—that is to say, the ability to use clues from eye gaze, facial expression, and other indicators of thought and attention to imagine what another person is thinking or believing.

By the end of the second year of life, young children are building up their ability to read the minds of other people, but this development slowly unfolds. Between the age of two and four, a theory of mind is still a work in progress, and the child is unable to grasp explicitly that his or her own belief can be different from the belief of another person. Yet, by about the age of four, the preschool child will have developed a relatively advanced theory of mind characteristic of adults—the four year old will understand that the beliefs, desires, and thoughts of other people may not be the same as their own. This transition has been measured using a test of false beliefs. For example, suppose that a young child observes the following scene. Sally enters the room where Anne is sitting and hides a marble in a basket. Sally then leaves the room, giving Anne a chance to trick Sally by getting up, retrieving the marble, and moving it to a box. Finally, Sally re-enters the room to get the marble. Where will she look for it? For three-year-old toddlers, without an advanced theory of mind, they respond that Sally will look in the box. They do not seem to be able to grasp that Sally holds in mind a mistaken belief about where the marble is, namely, in the basket where she left it. The three year olds assume that Sally's understanding of the situation is identical to their understanding. Yet, within another year, by the age of four, children readily grasp the notion that two people can hold different beliefs and that another person can hold a false belief. The four year olds respond that Sally will look for the marble in the basket.
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Between the age of three and four, the typical progression of human
brain development allows the child to read the mind of Sally, in a sense, and grasp that her perspective is distinct from the child's own.

Can the typical developmental progression of coming to recognize intentional agents go awry? It seems to in the developmental disorder known as autism. Autistic children can in some cases have normal levels of intelligence. In fact, autistic savants show extraordinary cognitive abilities in specific domains, such as artistic or mathematical abilities. Yet autistic children have difficulty seeing other people as intentional agents with minds of their own.
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They are in a sense blinded to a degree to the minds of others, a social form of blindness that disrupts interactions with other people and efforts to communicate. Autistic children instead risk becoming isolated in a world of their own making rather than fully experiencing the shared cultural world.

Imitation

Joint attention and the recognition of intentional agents are important milestones in the first important form of cultural learning. Without these two steps, the next step of social learning through the imitation of others cannot be taken. At around nine months of age, the infant begins to reproduce the intentional behavior of an adult.
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For example, if the caregiver models drinking from a cup, then the infant will try to imitate the behavior. The infant adopts the goal of wanting to get a drink and follows the behavioral lead of the adult in how to achieve it.

Less complicated kinds of imitation start practically at birth in face-to-face dyadic interactions between the infant and parent.
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If a father sticks out his tongue at his newborn son, the baby can stick out his tongue to mimic the parent's facial gesture. This shows that social learning begins at a very early age, preparing the infant for the more complex triadic imitation that emerges several months later. The nine-to-twelve-month-old-infant can recognize the parent as an intentional agent and can hold in mind the adult and an external object and the self in a triad of joint attention. During early childhood, all sorts of parental behaviors are imitated: “For example, a toddler may see her father using a telephone or computer keyboard and crawl up on the chair and babble into the receiver or poke the keys.”
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Cultural learning—observing and imitating the intentional actions or behavior strategies of others—provides a way for one generation to pass on its knowledge to the next generation. Learning in this way is certainly not limited to young children. For example, apprentices in crafts and trades learn skills through imitation and practice as well. Although imitation is an important form of cultural learning, it is not the only means by which knowledge can be faithfully passed from one generation to the next. A teacher can also directly instruct the learner in how to do something. Direct instruction forms the core of schooling as a way of propagating cultural practices through historical time. Another form of cultural learning depends on the invention of written language. Once the knowledge of a teacher has been written down, the learner can read the information without the teacher needing to be present. Instruction can thus also occur through reading, at least among literate learners.

DEEP ENCULTURATION AS UNIQUELY HUMAN

The cognitive development of other species, like us, depends on genes passed down from ancestors and on the influence of the current environment on the expression of the genes in the brain and body, what biologists call epigenetic factors. However, in human beings alone there is a deep or cognitive enculturation that structures the brain and mind in profound ways not seen in any other species. Parents, family, schools, church, and other institutions of society assume control of the child's cognitive development shortly after birth. The brain adapts to a culture filled with symbolic as well as material artifacts. For example, literacy brain circuits are developed for reading and writing as a consequence of children growing up in a social world of communication and linguistic symbols. Mathematical circuits emerge through schooling; these take the core concept of number prewired in the brain through genetic coding and grow a complex system of mathematical literacy. Musical literacy also alters the brain's architecture through immersion in a family and community of singing, dancing, and instruction in the musical arts.

Chimpanzee Traditions

Biologists have looked for behavioral traditions in different communities of wild chimpanzees. If any other species were to show signs of cultural evolution, one might expect something similar in our closest genetic relative. Research has shown that different groups maintain as many as thirty-nine different traditions.
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Other mammals, birds, and fish, far more distantly related to us, typically display only a single behavioral tradition and never more than a handful. To illustrate a chimpanzee tradition, consider the style of clasping hands used to initiate grooming. Whereas one group of chimpanzees clasped hands palm to palm, another group in a nearby region used a wrist-to-wrist style. As another example, the ways chimpanzees scratch each other’
s
backs also varies by community, some using a long, raking scratch and other groups preferring a short jabbing technique.

Most strikingly, a community of chimpanzees in the Republic of the Congo invented a pair of tools to fish for termites for food in their mounded nests.
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One tool is a stout stick that can be jammed down into the ground to expose a tunnel into the termite nest. Another tool is a slender probe that the chimpanzee first prepares by stripping its leaves, shortening it to a good length by biting, and then pulling it through the teeth to fashion a nice brush tip. This tool is then inserted into the tunnel to collect and extract the termites, like a fish on a hook. These termite-fishing methods have not been observed beyond this community. By contrast, some populations in Western Africa simply smash open the termite mound with large sticks and then grasp the insects with their hands.

Although chimpanzees have many more behavioral traditions than other species, they do not display a cumulative culture the way human beings do. For chimpanzees, there is little if any indication of innovation and improvement as a tradition is passed from one generation to the next. By contrast, we invent a material artifact, such as a tool, and then pass it down to the next generation, where it might be either improved upon or at least transmitted faithfully and not simply lost in the rubble of history. Through the ratchet effect, human culture progresses by building on the wisdom of the past. Human beings not only improve the sophistication of their material tools, but also do the same with symbolic artifacts of, say, language and art.

The cultural gulf between chimpanzees and humans is understandable for at least two reasons. First, the behavioral traditions and tools invented by chimpanzees are relatively simple and not readily modifiable into more complex, improved versions. They may lack the cognitive capacity needed to invent a more complex tradition or tool. Whereas human beings are endowed with a strong fluid intelligence that stems from our advanced working memory system, innovation is not second nature for chimpanzees. Second, the chimpanzee is not as adept at cultural learning through imitation as a human being is. The advanced social intelligence of human beings specifically equips us for cumulative culture in a way not seen in chimpanzees. This is not to say that apes cannot ape. But they are more likely to engage in a form of social learning known as emulation rather than imitation. By emulating the behavior of a model, one learns that the model did something to change the state of the environment. But the change in the environment is the focus of the learning rather than the specific behavioral strategy used by the model.

Emulation versus Imitation

Michael Tomasello, in
The Cultural Origins of Human Cognition
, observed that chimpanzees are very good at learning how to obtain goals by observing the behavior of their conspecifics.

For example, if a mother rolls a log and eats the insects underneath, her child will very likely follow suit. This is simply because the child learned from the mother's act that there are insects under the log—a fact she did not know and very likely would not have discovered on her own. But she did not learn from her mother how to roll a log or to eat insects; these are things she already knew how to do or could learn how to do on her own. (Thus, the youngster would have learned the same thing if the wind, rather than her mother, had caused the log to roll over and expose the ants.)
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Tomasello went on to describe an experiment that he and his colleagues conducted to contrast the emulation of chimpanzees with the imitation of human beings.
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They gave a rake-like tool to a chimpanzee, along with an object that was just out of reach. The rake was designed so it could be used
either in an efficient way to retrieve the object or in an inefficient way. The experiment was designed so that one group of chimpanzees saw a model that demonstrated how to use the rake efficiently while another group observed the inefficient method. The results showed that the chimpanzees used the rakes in all sorts of ways after watching the demonstration, and it made no difference at all whether they had seen the efficient or the inefficient demonstration. Thus, they learned through emulation that the rake could be used in some fashion to obtain the object, but they did not imitate the behavioral strategy for doing so.

The experiment was repeated with two-year-old children with a fascinating difference in outcome. The human children generally copied the method of using the rake that they saw in the demonstration assigned to them. This proves that they were imitating the strategy, not just emulating its effect on the environment. Most importantly, the children imitated the inefficient method just as faithfully as the efficient one! As a consequence, the children who saw the model use the rake in an inefficient way ended up with a poorer level of success in retrieving the object compared with the chimpanzees. The inclinations of human beings to imitate is so powerful that it can stand in the way of finding creative ways to solve problems that do not rely on reproducing the ways observed in the past. This is intriguing, for it shows that “imitative learning is thus not a ‘higher’ or ‘more intelligent’ learning strategy than emulation learning; it is simply a more social strategy.”
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Other experiments have documented the same conclusion; human beings are so attuned to the behavior of models that they imitate them even when it makes little sense to do so.
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Imagine a box with a desirable treat on the bottom and two openings, one on the side and one at the top. Further imagine that the top opening leads only to a platform in the middle of the box that prevents probing with a tool to reach the food on the bottom. A human model demonstrated how to get to the food by first trying the top opening and then moving the tool into the side opening to obtain the treat. When the box is covered so that the test subject cannot see inside, both chimpanzees and human beings followed the lead of the model—they both imitated what they saw the model do. The interesting question was what would happen when the box was made transparent, when it was possible to see that a platform in the middle prevented any success with using the tool in the top opening.
The results with this transparent box showed that “the chimpanzees switched from the imitative approach they had used with the opaque box to a relatively emulative strategy that focused on the crucial terminal work around the low hole.”
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Stunningly, the children continued to conform to what the model had done—they ignored what their own eyes told them and imitated the model!