That capacity starts early. There is ample evidence that human infants are pre-adapted by evolution to seek out other humans and engage with them.36 For example, babies pay attention to what others are looking at so they understand the link between gaze and actions – people tend to want what they look at. If an adult stares longer at one of two different toys, but then picks up the toy they were not looking at, babies are surprised.37 Where we look reveals the focus of our interest and desires, and this is something the baby understands intuitively.
Expressions are also a good indicator of what someone else is thinking. When an eighteen-month-old infant is offered broccoli or crackers, they usually choose the salty biscuits. Crackers are much tastier than broccoli to a baby. However, if they watch an adult wrinkle their nose at the sight of crackers, but make a smiley ‘num num’ face to the vegetable, the baby knows to offer them the broccoli if the adult then asks the baby to pass them something to eat.38 The baby can figure out what the adult likes.
But none of this people-watching really requires a theory of their minds. Likes and dislikes can be easily worked out by simply watching whether people smile or frown. We do this all the time, looking for external markers of behaviour that reveal preferences. Even animals can do this.39 As many pet owners can attest, animals learn when their masters are angry or pleased with them, but this does not require understanding what is on their master’s mind. Rather, to prove that we can understand what is really on someone else’s mind, we have to appreciate when they hold a mistaken or false belief.40 A belief is simply an idea that we think is true; but sometimes we may be mistaken. If you can understand that someone holds a false belief, then you can imagine what they are thinking even when what they are thinking is factually wrong. That’s a powerful level of insight into someone else’s worldview. For example, if you show me a confectionery box and ask me what is inside, then I am likely to say sweets or candy, depending which continent I am on. However, if you open it up and reveal that it actually contains pencils, then I will realize I was understandably mistaken. My belief was false. Three-year-olds will also make the same mistake.41 After all, they don’t have X-ray vision. But if you now ask me to imagine what my neighbour would reply if he were asked what is inside the box, I know that he too will make the same mistake as I initially did. I can understand that he will not know what is actually in the box. In contrast, a three-year-old will assume that someone else who comes along will know that there are pencils in the box and answer, ‘Pencils’. They don’t appreciate that others will also come to the wrong conclusion about what’s in the box and can hold the same false belief. By four years of age, most children understand that people will answer, ‘Candy’, when asked what’s in the box.
Psychologists think that young children initially lack a theory of mind when it comes to understanding mistaken beliefs.42 It’s as if they cannot take another’s perspective. In one classic experiment, children see a doll called ‘Sally’ hide her marble in a cupboard before she goes out. When she is out, another doll, ‘Anne’, comes in and takes Sally’s marble and hides it in the kitchen drawer. The critical question is where Sally thinks her marble is. When children watch this scenario, three-year-olds think that, on her return, Sally will look in the kitchen drawer for her marble, whereas four-year-olds say that she will look in the cupboard. Clearly, when you understand that people can hold false beliefs, you can lie to them to make them think something that isn’t true. When you consider how so much social manipulation involves deceiving others, you can understand why having a theory mind is a valuable tool. You can outwit others by leading them to false assumptions.
An underdeveloped theory of mind in children also explains why they can make such bad liars. Initially, when a child realizes that punishment is imminent – ‘Did you eat the cake?’ – they simply say no, despite the fact that they have chocolate cake smeared across their face. Only later do children get more sophisticated in generating plausible stories for why they might have the tell-tale chocolate on their face – invariably they blame someone else.
Theory of mind is really a form of mental perspective-taking – understanding things from another’s point of view – a ‘he thinks that she thinks’ sort of thing. In order to do this, you have to be able to keep track of what developmental psychologist Alison Gopnik43 calls ‘counterfactuals – the woulda-coulda-shoulda’s of life’. Counterfactuals are what enable you to imagine different scenarios, including what people may do in the future, based on what you know now. It’s how we second-guess others and, to do that, we have to possess the mental machinery to generate different possible outcomes and play them out in our heads. This is going to happen mostly in situations of social competition where you have to anticipate what others will do next, which maybe explains why theory of mind emerges earlier in children who have siblings.44 The constant battle to keep place in the pecking order means that children have to learn to outwit their brothers and sisters.
Mindblindness
Not everyone develops a theory of mind. In his book, The Empathic Brain, neuroscientist Christian Keysers45 describes his encounter with a young graduate student, Jerome, who is finishing his PhD in theoretical physics. His colleague Bruno Wicker introduced Jerome who, on entering the room, spoke with a flat voice and never looked Christian in the eyes.
Bruno: ‘We would like to ask you something.’ (Bruno shows Jerome a box of Danish cookies.) ‘What do you think is in this box?’
Jerome: ‘Cookies.’
Bruno then opened the box to reveal a set of colored pencils instead of the expected cookies.
(His female research assistant then enters the room.)
Bruno: ‘What do you think she would think the box contains?’
Jerome: ‘Colored pencils.’
Here is a man with the mental capacity to think about abstract properties of the universe that would baffle most of us and yet he cannot imagine what someone else might think is inside a cookie box. Jerome has autism – a developmental disorder that affects around one in 500 individuals,46 though this figure appears to be on the increase and depends largely on how you define it. In general, autism can be thought of as a disorder with three major disabilities: a profound lack of social skills, poor communication and repetitive behaviours. It is regarded as a spectrum disorder because individuals vary in the extent to which they are affected. Most are intellectually challenged, some are within the normal range, and a few may have rare abilities such as being able to tell you what day of the week any date in history falls upon. But all individuals with autism spectrum disorder have problems with social interactions.
These individuals have a problem with social interaction because they lack the repertoire of developmental social skills that enable humans to become the expert mind-readers. Over the course of early childhood, typical children increasingly become more sophisticated at understanding other people because of their developing theory of mind. By the time they are around four years of age, an average child sees other people as being goal-directed, purposeful, having preferences, desires, beliefs and even misconceptions.
Not only do typical children become intuitive mind-readers, but they also become councillors as well. They begin to understand other’s sadness, joy, disappointment and jealousy as emotional correlates of the behaviours that make humans do the things they do. Again, by four years of age, children have become expert at working the social arena. They will copy, imitate, mimic and generally empathize with others, thereby signalling that they too are part of the social circles that we all must join in order to become members of the tribe. They share the same socially contagious behaviours of crying, yawning, smiling, laughing and showing disgust.