MAGICAL BABIES
As it turns out, Piaget was wrong about ‘out of sight, out of mind’ for babies. We now know that they don’t think magically about physical objects. They are not deluded in thinking that their own thoughts make physical things materialize. Babies do know that a real world of objects exists out there. You just have to ask the question in the right way – one that obviously does not require language (because you may be waiting all day for an answer) and does not involve searching for hidden objects. How can this be done? Ironically, the ingenious answer involves a bit of magic.
Everybody likes a good magic trick. Why? Because we don’t believe in magic. If we really did think that objects can vanish into thin air, then a conjurer’s illusion would be of little surprise to us. Magic tricks work because they violate our beliefs about the world. They cause us to be surprised, to stare in wonder, to look puzzled, applaud, and then want to see it done again. The same is true to some extent with infants. They may not be able to give a round of applause and demand an encore, but they do look longer at the magical outcome of a conjurer’s trick. You can measure this simply by the amount of time they spend staring at an impossible outcome in comparison to a possible one.
Over the past twenty years, scientists have used this simple principle to reveal the workings of the baby mind.28 If babies look longer at a trick, then they must appreciate that some physical law is being broken. Somewhere inside their heads, there is some mental machinery clanking away trying to make sense of an illusion by paying more attention. For example, imagine you are a baby watching a puppet show. On the stage sits a Mickey Mouse doll. A screen comes down to hide the doll, and then a hand comes stage left to deposit another Mickey Mouse doll behind the screen. How many Mickey Mouses (or should that be Mickey Mice) are there behind the screen? Easy, you say, there are two. But when the screen is raised revealing three, you know something is amiss. The same is true for babies. They look longer at three dolls. They also look longer when only one doll is revealed, but not when there are two. They know one plus one equals two. By five months of age, babies have the basics of mental arithmetic.29
Hundreds of experiments have shown that babies can reason about similar unseen events in their head. They can think about hidden objects, where they are, how many there are, and even what they are made of. Where does this knowledge come from? Many such experiments show sophisticated and rapid learning that has led Harvard infant psychologist Liz Spelke to propose that some rules for object knowledge must be built in from birth in the same way the rules for learning language are.30 Evolution has provided babies with a set of principles to decode the ‘blooming, buzzing confusion’ that the real world presents to us each time we open our eyes:
Rule 1:
Objects do not go in and out of existence like the Cheshire Cat in Alice in Wonderland. Their solidity dictates that they are not phantoms that can move through walls. Likewise, other solid objects cannot move through them.
Rule 2:
Objects are bounded so that they do not break up and then come back together again. This rule helps to distinguish between solid objects and gloop such as applesauce or liquids.
Rule 3:
Objects move on continuous paths so that they cannot teleport from one part of the room to another part without being seen crossing in between.
Rule 4:
Objects generally only move when something else makes them move by force or collision. Otherwise, they are likely to be living things, which, as you will see in the next chapter, come with a whole different set of rules.
How do we know that these rules are operating in babies? For the simple reason that babies look longer when each of them is broken in a bit of stage-show magic. By applying the principles of conjuring and illusion, scientists have been able to show that young infants have knowledge about the physical world that they must be discovering for themselves. And, if they are figuring out the physical world by themselves, then it stands to reason that they must be thinking about other things in the world.
INTUITIVE THEORIES
The things we know best are the things we haven’t been taught.
– MARQUIS DE VAUVENARGUES
The magic trick experiments have revolutionized the way we interrogate babies about what they know. If you think about it, all the different things in the world have properties that make them what they are. Inanimate objects have inanimate object properties. Living things have living thing properties, and so on. If you can set up a magic show that violates properties of each of these things, then you can see if the baby spots the mistake.
In a game called twenty questions, you have to work out the identity of something that another player is thinking about. It starts off with the question, ‘Is it an animal, vegetable, or mineral?’ From there the player has to phrase each question to require a yes or no response. ‘Is it bigger than a bread box?’ ‘Does it come in more than one colour?’ If you can guess the identity within twenty questions, you win. An electronic handheld version called ‘20Q’ won the 2006 Toy of the Year Award from the American toy industry association. It’s remarkable. It can almost always figure out whatever obscure object you might have in mind. People find this amazing, but, there again, people overestimate how many different objects they think they know. The reason twenty questions starts with animal, vegetable, or mineral is that this division describes most of the different kinds of things there are in the natural world.
Babies also chop the natural world up into groups of different kinds of things. Not unlike twenty questions, they first decide whether something is an object, a living thing, or a living thing that possesses a mind. From very early on, children reason about the nature of inanimate objects as being different from living things that can move on their own and are alive.31 They also start to see living things as motivated by goals and intentions.32 In other words, they are beginning to think about the notion of what it means to have a mind. Well before young children have been taught anything at school, they are already reasoning about the physical world, the living world, and the psychological one. They are in effect little physicists, little biologists,
and little psychologists.33
However, the knowledge they have in each of these areas is more than just a list of facts. Their knowledge of the world is theorylike. What this means is that when babies encounter a new problem, they try to make sense of it in terms of what they already know. This is what theories do. They give us a framework in which to make sense of something. More importantly, theories allow children to make predictions in a new situation. For example, having established that a spoon pushed off the edge of a high-chair tray falls down, the baby will theorize that other solid objects should do the same and will happily explore this by dropping everything over the edge. The baby is beginning to understand the effects of gravity.
Babies also reason about people. Having witnessed that Mum will pick up the spoon and replace it on the table, they theorize that adults are predictable whereas the family hamster is not. They are beginning to understand that actions differ between living things and to appreciate goals and intentions as mental states. From the moment babies start to pay attention and anticipate events in the world, they are forming theories about how the world works. No one has to teach them about gravity or the mind. They are figuring these out for themselves. It is not even clear that they are fully aware of exactly what they are figuring out, but their thinking is not haphazard. These organized ways of thinking are the intuitive theories that all infants develop.34