According to available records, the youngest child convicted and executed for a crime in England was John Dean, aged around eight years. He was hanged in Abingdon for setting fire to two barns in the nearby town of Windsor in 1629. At the time, the age of criminal responsibility was seven years, at which point children were considered to be little adults. Indeed, this is how they were often portrayed in paintings from that period.
In Van Dyck’s (1637) portrait of the children of Charles I, they look like miniature adults. Charles II, the boy in the painting, is only seven years old, yet he is shown with the posture of an adult, with feet crossed in a casual lean against the wall. The portrait reflects the prevailing attitude of the time that children simply lacked the wisdom of experience and that with training they would become acceptable to society. Like empty vessels, they needed to be filled up with information and instructed how to behave.
John Locke (1632–1704), the English philosopher, captured this view of the child as a blank canvas:
Let us then suppose the mind to be, as we say, white paper void of all characters without any ideas. How comes it to be furnished? Whence comes it by the vast store which the busy and boundless fancy of man has painted on it with an almost endless variety? Whence has it all the materials of reason and knowledge? To this I answer, in one word, from EXPERIENCE.1
Figure 1: Children depicted as ‘Little Adults’
Locke described the infant’s mind as a ‘tabula rasa’ or blank slate. Not only was the infant’s mind considered empty, it was one that was faced with the daunting task of making sense of a complex and confusing new world of sensations and experience that the American psychologist William James would later describe in 1890 as a ‘blooming, buzzing confusion’.2
However, Locke’s blank slate view is not plausible, nor is the newborn’s world completely confusing as James imagined. As the Prussian philosopher Immanuel Kant3 (1724–1804) pointed out, blank slates would not work unless they were already set up to detect the structures of the world. There has to be some organization built in in order to determine what constitutes a pattern in the first place. Consider how complicated vision would be without some pre-existing knowledge. You cannot begin to understand the world around you unless you have some inkling of what you are looking for. In order to perceive the world, you need to distinguish objects from backgrounds and determine where one object begins and another ends. We rarely consider these as problems because vision is so effortless. It is only when you try to build a machine that can see that the difficulty becomes all too obvious.
In 1966, Marvin Minsky, one of the pioneers of artificial intelligence, is said to have asked one of his undergraduate students at MIT to ‘spend the summer linking a camera to a computer and getting the computer to describe what it saw’. Presumably Minsky thought that the problem was easy enough that it should take the duration of a summer vacation for a student to solve. That was almost fifty years ago and thousands of professional scientists are still working on how to make machines see like humans.
Back in the 1960s, artificial intelligence was a new field of science that promised us a labour-saving future where robots clean the house, wash the dishes and basically perform all the mundane chores humans hate to do. Since then we have witnessed remarkable developments in computing and technology and there are certainly very smart vacuum cleaners and dishwashers. But we still have not been able to build a robot that perceives the world like a human. They may look human but they are unable to solve some of the simplest problems we take for granted, ones that most babies master before their first birthday.
Another reason why the blank slate cannot be true is because it turns out to be physiologically wrong. Our senses are pre-configured in anticipation of the sorts of signals that we can expect as babies. We do not have to learn to distinguish different colours, or that a boundary between brightness and darkness corresponds to an edge. If you measure from brain cells that react to sensation in unborn animals before they have had any experience of the external world, they will already respond to features that they have not yet encountered.Human newborns will show immediate preferences for some patterns before they have had any time to learn them, so their world is not totally confusing. These early capabilities show that there is considerable formatting in the newborn’s brain that enables them to make sense of experiences.
Figure 2: Spot the difference
Like a computer that you buy from a store, the brain already comes with an operating system installed. What you eventually store on it really comes down to what you do with it. Biology and experience work together to generate a developing mind, adapted to the external world. That process is one of discovery as each child goes about decoding the complexity of the world around them by using the tools that evolution has bestowed upon them.
Getting wired up
The brain of any animal is as complex as it needs to be to solve the world problems that the creature has evolved to accomplish. In other words, the more versatile an animal’s behaviour, the more sophisticated their brain.4 This versatility comes from the capacity to learn – storing memories as patterns of electrical connectivity in the specialized brain cells that alter in response to experiences. In the human adult, the brain is comprised of an estimated 170 billion cells, of which 86 billion are neurons.5 The neuron is the basic building block of the brain’s communication processes that support thoughts and actions.
Each neuron looks like a many-tentacled creature from outer space with a body from which branch thousands of receptors or dendrites that receive incoming signals from other neurons. When the sum of incoming nerve impulses reaches a critical threshold, the receiving neuron then discharges its own impulse down the axon to set off another chain reaction of communication. In this way, each neuron acts like a miniature microprocessor. The patterns of nerve impulses that spread across the vast network of trillions of neural connections are the language of the brain as information is received, processed, transmitted and stored in these networks. The presentations of experiences become re-presented, or representations – neural patterns that reflect experiences and the internal computing processes our brains perform when interpreting information.
One of the more surprising discoveries about brain development is that human infants are born with almost the full complement of neurons that they will have as an adult. Yet the newborn brain weighs about a third of the adult brain. Within a year, it is about three-quarters the size of the adult brain.6 Connections form at a rate of 40,000 per second in the newborn, which is over 3 billion per day.7 Eventually, the length connecting fibres will extend to an estimated 150–180,000 km – enough wiring within an individual human brain to circumnavigate the world’s equator four times.8 In fact, the bulk of the brain is mostly connections, with the neurons squeezed into 3–4mm of the outer layer that covers the surface of the brain, called the cortex after the Latin word for ‘bark’.