2Sometimes people store more than the gist. A photographic memory, or eidetic memory, refers to a capacity to maintain access to an event as if one were still perceiving it. This is not to say that eidetikers remember everything they experience in this way, but they may for instance view a picture for a minute and then replicate it in detail. Other astounding feats of memory, such as the rapid learning of lists, numbers, or names, are typically the result of carefully deployed, deliberate memorization techniques.
3Science magazine considered new evidence for this one of the top ten scientific breakthroughs of 2007.
4When the problem and solution were presented in the same situation, both age groups can solve the puzzle. In a follow-up, children could select a solution and then had to wait for five minutes before they could implement the solution. Again, children from about age four can do this task.
5Juvenile mammals tend to engage in play behavior that may function as preparation. They can, for example, practice the moves that later will allow them to hunt or fight. Such behavior is universal and limited to a few capacities. It thus seems to be an instinctual behavioral predisposition, rather than the result of the individual animal anticipating a particular future event for which it must train.
6One high-profile study suggested that scrub jays can adjust their caching of food according to what they could expect to desire in the future. Unfortunately, the rich interpretations were not convincing for a variety of reasons, one of which being that the birds did not actually increasingly store the relevant food. Very recent work on Eurasian jays looks more promising, but new killjoy accounts have also emerged. In another study, two squirrel monkeys were given a choice between one and four pieces of thirst-inducing date. When they selected the larger reward, they did not get any water for three hours. The monkeys gradually changed their choices, preferring the smaller quantity, leading the authors to conclude that the monkeys anticipate their future thirst. However, the gradual change suggests associative learning, and it is unclear why, if they did understand, they then did not simply select the four pieces and only eat one, leaving the others for a time when enough water was available. An attempt to replicate the results with rhesus monkeys failed.
SIX
Mind Readers
Of all the species on Earth, only humans possess . . . the ability to infer what others are thinking.
—CARL ZIMMER
WHEN I TELL PEOPLE I am a psychologist, they sometimes respond warily, suspicious that I can peek directly into their minds. Alas, I cannot. In spite of attempts to demonstrate telepathy, there is no proof that anyone can communicate using only their minds. During the cold war the United States and the Soviet Union invested considerable effort into attempts to harness purported psychic abilities for their military programs—with the only positive apparent outcome being satirical movies, such as The Men Who Stare at Goats, which lampooned these earnest projects. As much as I like the idea of parapsychological powers, there simply is no compelling evidence for them. Minds are private; we can never be entirely sure what goes on in somebody else’s head. On a fundamental level I cannot know what it is like for you to see the color green, to want something badly, to know your limits, to feel lonely, to anticipate something, or to have a toothache. Yet, just as we can time travel without time machines, we can read minds without telepathy.
Indeed, we are avid mind readers. We think, and often worry, about what others feel, desire, and believe. In conversation we customize what we say based on what we think the other person wants and does or does not know. We care about making others happy and empathize when they are sad. We may try to put them at ease, to tickle their fancy or blow their minds. We regularly interpret even the simplest acts in terms of mental states.1 A brief rolling of the eyes may be interpreted as disdain, contempt, or frustration. If you had seen me get up and go to the fridge a moment ago, you could have explained that I wanted a drink and believed I might find cold water in the fridge. Knowing what others desire and think is immensely useful for predicting what they are going to do. We live in a world of minds aware of other minds, and mind reading is absolutely fundamental to our social lives.
Cognitive psychologists call this ability “theory of mind.” “Theory” here refers to the fundamental fact that we can only theorize about the mental states of others. There has been considerable debate about how we do this. Some scholars argue that we reason about others’ minds much as we do science. We develop a commonsense psychology—ideas about desires and beliefs and how they influence actions—which we adjust and fine-tune in the light of evidence we encounter. Others argue that, because the only direct evidence we have is our own mind, we understand others’ minds by imagining their situation and simulating their experiences. This requires mental scenario building, as in the theater metaphor I discussed in the previous chapter. We can stage others’ situations and therefore think about their mental experiences.
It is likely that both answers contain some element of truth. We seem to be able to put ourselves into another’s shoes and imagine how we would feel or what we would think if we were in their situation. With sufficient experience, we may also develop shortcuts that allow us to rapidly infer what is likely to be on someone else’s mind. In other words, you can engage in both instant recognition and elaborate simulation of others’ mental states. For example, you may immediately recognize that someone who was cheated is likely to be upset, but you can also pause to imagine what this must have really been like, and so more thoroughly appreciate that person’s perspective. We seem to read each others’ minds in both these ways. We have a fundamental urge to link our minds: to understand and to be understood.
EVEN CHILDREN APPEAR TO HAVE a basic drive to wire their minds into the social network of other minds. Babies have a special affinity for social stimuli, such as eyes and faces. Mothers typically try to establish prolonged eye contact as soon as possible, and newborns appear to be prepared for it. When given the option, they prefer to look at open eyes rather than shut eyes. As adults, we use eye contact to make apparent mind contact, for instance, when inviting interaction.2 As the proverb goes: the eyes are the window to the soul. Through extensive face-to-face interactions, parents and infants build deep bonds.3
From two months onwards, infants begin to smile when their parents smile at them. Over the next months they learn to follow gaze, at first to objects within their visual field and later to points of interest behind them. Infants and adults begin to attend to the same objects and mutually interact with them—for instance, in give-and-take games. The developmental psychologist Chris Moore has highlighted the fundamental importance of these three-way (parent, infant, object) interactions for children’s social-cognitive learning. Infants start to check the facial reaction of their parents to glean information about how to handle ambiguous situations.
By the end of the first year infants start to point to objects. It was a memorable day when my son, Timo, suddenly began to point—as if the penny had dropped, he pointed out everything he was excited about. He had gained the power to direct my attention to objects in the world. And he could get me to fetch them. Pointing is more than a tool children use for manipulating parents to get what they want, however. They draw others’ attention to things because they are interested in them, often without receiving any reward other than shared attention for these efforts. They are strongly motivated to keep making links with minds around them.
With the development of language, the opportunities for making such links grow. Language turns mind reading into mind telling. We tell each other our experiences, opinions, wants, and needs. When an infant points to an object, adults typically name it. By the end of the first year infants articulate their first words, and adults increasingly point out new words during bouts of joint attention. In a sense, words themselves provide the opportunity for more effective sharing in attention. You say a word, and the attention of people around you is drawn to what it stands for. Koala. One amazing property of words,
of course, is that they allow us to share attention not only to what is around us but to things that are not there. We may not be able to point to last week’s guest, tonight’s sunset, or cute, eucalyptus-munching marsupials, but we can raise them in conversation. Language allows us to jointly consider stuff that we only represent in our minds. You, dear reader, have just had your attention drawn to that very fact.
More than simply drawing attention to things, language allows us to comment on them. We can transmit potentially useful information about absent objects and events from one mind to another. Even toddlers can do this: “floor wet—naughty dog.” Of course, they do not always have enlightening information to contribute. Yet they often express a ferocious appetite to get involved in these exchanges. When four-year-old Timo tells my spouse, Chris, and me something, two-year-old Nina frequently, and excitedly, interrupts. She calls out, “Mama, Mama, Mama; Papa, Papa, Papa,” until she finally gets our attention, only to repeat what Timo has already said—or to inform us again of the fact that “I a girl; Timo boy.” Nina has no new information, but she won’t stop until her contribution is properly acknowledged. Timo has long figured out the importance of adding new information and contributes accordingly (rolling his eyes at Nina’s repetitions). He, like most adults, takes particular delight in sharing a surprising morsel of information or even a secret. He wants to know how you feel and makes sure you know how he feels.
OUR URGE TO LINK OUR minds permeates much of what we do. We spend a lot of our social lives exchanging gossip, opinions, and advice. We listen to stories, read books, or watch shows that let us see the world from someone else’s perspective. Technological advances, from radio to the internet, allow us to wire our minds together in ever faster and more efficient ways. Today, what is on someone’s mind can spread to millions of other minds across the globe within minutes.
Nested processes are also involved in mind reading. I am currently thinking about what you might be thinking about my thinking about thinking about thinking. Recursion and our open-ended capacity to imagine different scenarios appear to be crucial not only for language and mental time travel but also for theory of mind. Indeed, one of the main points in Michael Corballis’s and my original paper on mental time travel was that the same mental machinery we use to simulate past and future events may be used to simulate other people’s minds. I long thought this was an original idea, but Nick Humphrey pointed out to me—and I need to embed this further, because since then Chris Moore told me that Nick learned it from him—that the essayist William Hazlitt had linked mind reading to foresight a couple of hundred years ago when he wrote: “The imagination . . . must carry me out of myself into the feelings of others by one and the same process by which I am thrown forward as it were into my future being, and interested in it.”
We may like or dislike our thoughts or desires and, to embed this further, evaluate our own evaluations. Because we can imagine past and future scenarios, we can reflect on our own past mental states (e.g., I should have known) and imagine future states (e.g., I will not get upset) just as we can about those of others (e.g., she will be happy about that). Being interested in our future well-being, we may decide to change present behaviors, even if they are currently enjoyable. For instance, you may decide to skip the next schnapps and start drinking water instead, to save your self of tomorrow from a wicked hangover. It can be difficult looking after not only your present desires but also those of your future self, as anyone who ever tried to give up smoking can testify. But we can aim to change. Reading our own future minds, we may realize that we will be, say, embarrassed because we are completely underprepared for what is ahead—unless we do something. So we may choose to practice skills we anticipate needing to be better at or seek information that we foresee will be useful later. This adds to our sense of free will as, to some extent, we can attempt to deliberately shape our future self. Of course, as noted earlier, people vary considerably in how much they take their future into account.
People also vary in how much they worry about the minds of others. Males and females, on average, tend to differ in the time and effort they put into mind reading. (No prize for guessing which sex is less inclined to think about others’ minds.) It has been suggested that some mental disorders are extreme versions of these female and male tendencies. People with paranoid schizophrenia tend to spend a lot of time pondering complex ideas about what other minds might be up to, whereas people with autism characteristically think very little about what is on others’ minds. There has been a lot of research on disorders of theory of mind in recent years. Autism research, in particular, has frequently been driven by an interest in autistic people’s peculiar limits to making mental connections with those around them.
In spite of some diversity in people’s particular beliefs about minds,4 basic mind-reading capacities are otherwise universal. Across cultures, for instance, people can recognize the facial expressions of our basic feelings; you can recognize fear, anger, disgust, surprise, sadness, and happiness in people from any culture as easily as they can recognize these emotions in you. As mind reading is fundamental to human interaction and cooperation, it is another good candidate for a uniquely human characteristic. Indeed, several prominent comparative researchers have argued that other animals do not read minds. The assumption is, although they probably have minds of their own, they might not make inferences about the not directly observable minds of others. A provocative killjoy review, for example, was titled: “On the lack of evidence that nonhuman animals possess anything remotely resembling a ‘theory of mind.’”
THE NOW POPULAR STUDY OF theory of mind actually began with a paper on chimpanzee cognition. In 1978 the comparative psychologists David Premack and Guy Woodruff published an article in the inaugural volume of Behavioral and Brain Sciences that kick-started this entire research area. They reported results of studies with a chimpanzee called Sarah that suggested she was reasoning about minds. Sarah was presented with short videos of a human actor facing a problem such as trying to get out of a cage, and then with a selection of photos of which one depicted something crucial, such as keys, to achieving the man’s goal. She reliably selected the correct solution. This behavior had three curious apparent implications. First, it seemed to imply that the chimpanzee could make sense of both videos and photos, and was able to relate the two (as we saw in Chapter 4, this competence has since been substantiated). Second, it suggested that the chimpanzee knew a thing or two about problem solving (we will examine that issue in the next chapter). Third, and most important to the authors, it appeared that she attributed an intention to the actor in the video: she seemed to infer what the actor was trying to achieve. Intention is a mental state, and Premack and Woodruff therefore suggested that chimpanzees have a theory of mind.
Behavioral and Brain Sciences is an unusual journal in that it publishes dozens of commentaries on a target article as well as a reply from the initial authors. The commentaries to this article raised various problems with Premack and Woodruff’s experimental design, making leaner interpretations possible. Nevertheless, they underscored the importance of the core question: If even chimpanzees might reason about minds, how can human scientists—particularly the remaining hard-core behaviorists—ignore the mind in their theories of behavior?
Three commentators scratched where it itched the most. They independently spelled out a solution to the problem of how one could unequivocally demonstrate that an animal or a child is reasoning about the minds of others. They argued that one needs to show that the individual in question understands that others act according to how they see the world, regardless of whether these views are factually true or not. In the case of true beliefs, one’s views and reality are by definition identical, and there is therefore no empirical way of distinguishing whether somebody’s actions are based on observable reality or on an inferred mental state in the other. In the case of false beliefs, however, mind and reality diverge, and someone who realizes this can predict the misg
uided actions of others who hold false beliefs. To understand that someone falsely believes something, one needs to be able to think about beliefs and their relationship to the world. This requires similar nested processes to the ones we encountered in Chapter 4 with four-year-old Rory painting herself painting a picture. Rory demonstrated an understanding of the representational relation between a picture and what it depicts. Reflecting on this relation (meta-representation) allows you to ask to what extent your picture correctly depicts the real world and what you got wrong. Similar reflections allow you to ask to what extent the beliefs of other people represent or misrepresent reality. If we can show that a child or an animal expects someone else’s behavior to be based on false beliefs, they demonstrate mind reading.
In 1983 the developmental psychologists Heinz Wimmer and Joseph Perner published their seminal studies on false-belief understanding in children. They told stories about a character, Maxi, who had put his chocolate somewhere, only for his mother to move it elsewhere during his absence. The children were then simply asked to predict where Maxi would look for the chocolate. Wimmer and Perner’s study, and the hundreds of variations that followed, found that young children persistently claim that Maxi will look where the mother had moved the chocolate. Older children, however, can put their own knowledge of the facts aside and realize Maxi will first unsuccessfully search for the chocolate where he had put it. They appreciate that Maxi’s search will be based on his false belief about where the chocolate is, rather than on what the observing child knows to be its true location. At this stage, then, children understand that people generally act according to how they represent the world—whether these views are correct or not. They can now take this into account in their conversations (as we saw in Chapter 4). They are certified mind readers.
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