The Domesticated Brain: A Pelican Introduction (Pelican Books)

Figure 5: Hands-free adult activates switch in A, whereas adult’s arms are constrained in B (image courtesy of Gergely Csibra and György Gergely)

Developmental psychologist Cristine Legare at the University of Texas at Austin, thinks that this early blind imitation observed in children has profound implications for our species. Along with her anthropologist colleague Harvey Whitehouse from Oxford University, she has been looking at the origins of human rituals.⁵⁰ Rituals are the activities that bind humans together – acts with symbolic significance that demonstrate that members of a group have shared values. All cultures have rituals for various events that are typically major transitions in life – birth, adolescence, marriage and death. These events punctuate our lives and are often associated with religious beliefs and ceremonies. The rituals themselves are typically inscrutable. There is no inherent logic to them. In that sense there are no causal laws operating, but if you don’t follow the rules then the ritual is violated. There is something about carrying them out in the correct way which gives rituals their potency. Likewise, Legare has shown that four- to six-year-olds are more likely to copy a behaviour step by step that has no obvious goal compared to one that does. In doing so, the child may be beginning to understand that there are some activities that others engage in that have no purpose but must be important precisely because they serve no obvious goal.⁵¹

Getting into someone else’s head

You cannot directly see other people’s intentions, but you have to assume that they have them. This is called mentalizing – assuming that other people are intentional because they have minds. People are not random, but rather do things on purpose because they have goals that control their behaviour. In one study,⁵² twelve-month-olds watched an experimenter look at one of two stuffed animal toys and exclaim, ‘Ooh, look at the kitty!’ A screen was then lowered and raised to reveal the adult holding either the kitten or the other toy. If the adult was revealed holding the other toy, the babies looked longer – they were confused by her intentions. They interpret people as doing things for a reason. If mum is looking at the sugar bowl on the table, then she is likely to pick it up but not the salt-shaker that she has not been looking at. When mum looks at and then walks over to the fridge, she does so to open it. Infants are building up an expanding repertoire of contingencies – knowing that people behave in predictable ways. When babies think that something has a mind because it appears to act as if it has purpose, they will attempt to engage in joint attention. They will even copy a robot if it appears to have a mind. By simply interacting with a baby and responding every time the baby makes a noise or an action, the robot soon becomes an intentional agent, so that babies will actively try to engage the machine and even imitate its actions.⁵³

In contrast, animals do not imitate spontaneously as an attempt to initiate or engage in a social exchange. They may have the capacity for mentalizing, but invariably this is limited to situations that satisfy self-serving needs. For example, amorous male apes and monkeys will manoeuvre female partners out of the line of sight of dominant males in order to copulate surreptitiously.⁵⁴ Many animals will steal food if they believe that others cannot see the theft. All of these abilities of perspective taking are heightened when there is potential danger from a competitor. However, it is not clear that these evasive actions really involve mentalizing. I know that I can avoid the strike of a snake if I approach from out of its line of sight in much the same way that I can avoid a tumbling boulder if I coordinate my actions correctly. In neither situation do I attribute mental states. I simply observe the actions and reason about what is relevant information. To establish mentalizing, there needs to be evidence of the attribution of beliefs – states of mind that individuals hold to be true about the world in the absence of any direct evidence. If I think you have a belief, then I assume that you hold certain expectations about the world to be true.

Even then, one could attribute belief to others simply by putting yourself in their shoes. For example, we can both separately enter and exit a hotel room and I can describe what I believe you saw based on my own experience. I would reason that because we both went into the same room, you must have seen what I saw. However, that need not be true. You might have had your eyes shut or something in the room might have changed, in which case I would be mistaken. For true mentalizing ability, you need to be able to understand that someone else might hold a different view from yours and indeed be completely wrong about the true state of the world. In other words, the litmus test for real mentalizing is the understanding that someone can hold a false belief.

Consider the following test. If I were to show you a confectionery box with ‘M&Ms’ written on it and ask you what is inside, then in all likelihood you would answer ‘M&Ms’. However, if I open it up to reveal pencils, then you should be a little surprised and possibly a little annoyed because you expected a chocolate treat. If I ask you what you originally thought was in the box, you would say ‘M&Ms’ because you understand that you had a false belief. This may seem trivially easy, but most three-year-olds give the wrong answer and claim that they thought there were pencils in the box.⁵⁵ It’s as if they have completely rewritten history to fit with what they now know to be true. They do not understand that they held a false belief. Understanding that someone can be mistaken is part of a capability called theory of mind and children operate with an increasingly complex set of assumptions about the minds of others.

If three-year-olds do not understand that they were mistaken, then it is not too surprising that they are unable to attribute false beliefs to others. If I ask you what someone else will answer when posed the same question about what’s in the box, then you understand that they, too, should answer ‘M&Ms’. You can see things from their perspective and understand that they will also have a false belief. Again, three-year-olds give the wrong answer and say pencils. It’s as if they cannot easily take another person’s perspective.

When young children act in this self-centred view they are said to be egocentric because they view the world exclusively from their own perspective. If you show young children a model layout on a tabletop of a mountain range with different landmarks and buildings and then ask them to select a photograph that corresponds to the view they can see, three-year-olds correctly choose the one that matches their own perspective. However, when asked to choose the picture that corresponds to the view that someone else standing on the opposite side of the table can see, they typically choose again the photograph that matches their own.⁵⁶

Young children cannot easily formulate a mental picture of what it is like to see the world from someone else’s viewpoint. The classic demonstration of this false belief perspective involves two dolls, Sally and Anne.⁵⁷ In the Sally–Anne task, Sally has a marble that she puts in a toy chest before saying goodbye to Anne and leaving the house. Whilst she is out, Anne moves the marble from the toy chest and places it in the cupboard under the sink in the kitchen. The child is asked where Sally will look for her marble. Adults easily know that Sally will look in the original location. After all, she does not know that Anne moved the marble and she isn’t psychic! Again, three-year-olds fail the test and say Sally will look in the cupboard in the kitchen, under the sink.

Why does it take so long for young children to understand that others can be mistaken? After all, infants understand that adults behave purposefully when watching their actions. One explanation is that young children do not yet understand that others have minds that can harbour false beliefs. Another explanation is that these tests require individuals to make a response that runs counter to what they know to be true. They have to actively ignore the true state of the world. If the task requirements are changed so that the need to respond is taken away, then a different picture emerges. One study examining the looking behaviour of infants reveals that they will look longer when Sally, who should hold a false belief, goes to the correct location as if she knew that her marble had been moved to a new location.⁵⁸ Sally’s psychic ability creates a violation of expectancy in the infants, so that they are surprised.

Appreciating that others can have false beliefs appears to be uniquely human, as there is no compelling evidence that other animals can acquire this aspect of theory of mind. As noted earlier, they can consider another’s perspective, which is how animals learn to deceive or pay attention to potential competitors; but they do not reliably pass tasks that require understanding that another holds a false belief. When tested on a similar non-verbal version of the Sally–Anne task, apes fail when required to make a choice by looking for food in one of two locations; but like human infants, they seem to register some indecision by looking longer or backwards and forwards between locations when there has been a surreptitious switch of target from one hiding place to the next.⁵⁹ Together, the looking measure suggests that there is some rudimentary knowledge about mentalizing present in both apes and young infants. However, only in humans does that understanding develop into a full theory of mind that we observe in typical four-year-olds.

Working out what others know is not always as trivially easy as the Sally–Anne task. Consider more complicated plots with more characters and more changes of events. When someone says ‘I know that she knows that he knows’, then they are applying multiple theories of mind. Keeping track of who knows what can easily become more difficult with each layer of plot added. Even then, you have to pay attention because if you miss a key step or forget who did what, you get it wrong.

Add to this the trouble with knowledge. When we know something is true, it is harder to ignore the content of our own minds when attributing a false belief to others.⁶⁰ We have to actively suppress our own knowledge in order to correctly identify the state of mind in another. As we shall see later, in Chapter 4, deciding not to do something requires actively doing something, which may be compromised in young children and absent in most other animals. So even adults who pass Sally–Anne tasks take longer to correctly attribute false beliefs to others. They are also much slower to solve false-belief situations when you give them a second task that occupies their own minds. It takes effort to think carefully about what others are thinking. Also, it is not clear that adults always employ a theory of mind during most social interactions.⁶¹ When you open the door for someone, do you really try to work out what his or her intentions are or do you mindlessly execute an action out of habit? Just because we can generate a theory of mind does not mean that we always do.

New York psychologist Lawrence Hirschfeld argues that while mentalizing through a theory of mind might be one way of predicting and interpreting someone’s behaviour, a better strategy, which is more accurate and efficient, is to make certain assumptions about the situation. In many of our interactions with others, we do not try to infer what is on their mind at all. Holding doors open for others, for example, is a mindless act, as are many of our social interactions.⁶² This is because humans may not be that good at attributing the correct mental state to others in the first place but they are better at reading what is normal behaviour in different contexts. Rather, we learn to apply a theory of society interpretation to the motivation of individuals – what people typically do in a particular situation. This would be based on learning about different members of the group as defined by the different categories they occupy, such as age and gender.

We operate with stereotypes, which lead us to assume that people will behave in certain predictable ways based on past experiences. This may actually be the default strategy for reasoning about other minds. In other words, it is when people do something we regard as unusual that triggers our mentalizing, as in, ‘What the hell were they thinking?’ This is when our false-belief reasoning is switched on, in an attempt to rationalize another’s actions. The idea that children learn about such exceptions to normality is supported by studies that show they are more likely to seek an explanation when they encounter variability in another’s behaviour.⁶³ They are also more interested in inconsistent outcomes – like detectives trying to solve puzzling behaviour.⁶⁴ They seem driven to try to understand the social world around them by making sense of people as predictable agents. Children need to learn what is typical for certain individuals as opposed to what is typical for most people.

How we make up our minds

Babies are clearly not just little adults, so what sort of creature are they? They are not blank slates: they are born with a brain that is already prepared for learning about the world. They have an instinct to learn. The development of the mind through learning must be the interaction between brain and the environment, shaped by mechanisms that have evolved to make sense of the world. But how much is built in by evolution and how much of it comes from experience?

As complicated animals, we engage in complex levels of analysis of the world. We have raw sensations streaming in through the senses that have to be organized into meaningful patterns that reflect information and structure in the environment. It would be a blooming buzzing confusion if it were not for the fact that we have some rules about how to make sense of our senses. These are the perceptual processes in the brain that detect and generate patterns. However, perceptions are only of use if they can be stored and recruited for future reference in order to plan behaviours. This is the job of cognition or thought. We can think about what we have learned and apply that knowledge to predict what to do next in a situation.

For young children, much of that world is a social one because they are so reliant on others for their survival. In the same way that we are adapted to understand some features of the physical environment, we also seem to be adapted to learning about others. Rudimentary social systems need to be fine-tuned or switched on by experience so that we can begin to understand people.

Some animals can also read other’s behaviours, but only when it is in their interest to benefit. Most animals are selfish, with little concern for others. In contrast, during the first year, a human baby’s social interactions with adults are rich and numerous but it is not clear that infants fully understand that the adult has a mind of their own yet. Without language, it is not clear that we could ever know what a baby is thinking about others. Maybe they are just like meerkats who automatically follow another’s direction of attention. However, as they grow, babies become more interactive with the world around them and seek out the attention of others. They may not have language by their first birthday but they are already communicating and reading non-verbal signals. They have gestures, squeal, blow raspberries, pull faces, protest, throw toys, point out things of interest, show fear or happiness and, of course, cry. Not only can they signal to adults what’s on their mind or at least when they are happy or unhappy, but they are beginning to understand that adults have minds too. When we can understand the minds of others, we can predict what they will do in the future. That is an enormous advantage when making sense of those around us.

Knowing what someone will do by reading their mind is one of the most powerful things our brains can do. When you know what someone else is thinking, you can manipulate and out-manoeuvre them for strategic advantage, just like Machiavelli. Even when you are not in competition with others, you still need the ability to know what they are thinking. Before language evolved, it would have been critical to understand what was on someone else’s mind so that you both could share the same perspective. You have to be able to put yourself in someone else’s situation in order to understand their intentions.

From sensation to culture, social mechanisms form a multi-layered system that is embedded in the newborn brain through natural selection but ultimately shaped and operated within a cultural environment. They are the tools that bind us together in a shared world. But there are other mechanisms that bind us together – we do more than share attention and interests, we also share emotions. From the very beginning, we are immersed in an emotional world where others make us feel happy or make us feel sad. The drive to have children may come from our selfish genes, but these genes also build the mechanisms that fuel our behaviour by providing feelings. Who we become is largely shaped by the emotions that motivate us, but these drives can be shaped by early experiences that leave a surprising legacy.