Baby Monitor

By Steven Pinker

One great blooming, buzzing confusion." That's how William James, writing more than a century ago, described the inner world of infants. Babies, unaware of the objects and people outside their bodies, see a kaleidoscope of shimmering pixels, he supposed. The famous Swiss psychologist Jean Piaget agreed: not until they are two years old do children fully appreciate that the world contains things that behave in predictable ways.

Nowadays every psychology student is taught that James and Piaget were wrong. From their earliest months, in fact, children interpret the world as a real and predictable place. It's the parents of an infant who experience the world as a blooming, buzzing confusion, says one psychologist. This new understanding is largely the legacy of Harvard psychologist Elizabeth Spelke.

How do you even begin to plumb the mind of a baby? Infants are harder to study than the usual subjects of psychological research--rats and college sophomores. Infants can't talk, they don't like being conditioned, and they react to most experimental procedures by crying or worse.

Spelke perfected a technique that capitalizes on one thing babies are good at: getting bored. Show a baby some objects, partly blocked by a screen, doing the same thing over and over, and most will tire and look away. Now show them what they had been missing. Some objects roll or fall, just as any grownup would expect. But others, thanks to trapdoors or hidden compartments, defy the laws of physics. They pass through barriers, or disappear and reappear. Are the babies surprised? Do they look longer at the impossible events, as if trying to figure out what just happened?

Remarkably, they do. Babies as young as three months old, an age at which their visual brains have just been wired up, can be surprised by magical events. They must expect the world to be nonmagical. They expect it to be a place where objects obey laws.

Spelke's ingenuity lies not just in showing that babies are smarter than we thought but also in exploring how they think and learn. Babies are born with no knowledge of how the world works; they have to learn. But how? Parakeets learn speech, and VCRs "learn" sights and sounds. Human learning must be more sophisticated.

Philosophers like Leibniz and Kant hypothesized that the mind innately thinks in such categories as space, time, number, causation and human intentions. Spelke turned this philosophy into experimental science and showed that infants have an abstract understanding of these categories of reality. They know that objects continue to exist even when you don't look at them and that they can't pass through barriers. Other psychologists--some of them her students--have documented when in the first year of life the other basic categories come online. With these scaffolds in place, babies can understand the world as they are exposed to it.

Spelke is now working with animal psychologists to investigate the minds of other nonverbal creatures, like monkeys. When parents inevitably ask for advice, Spelke tells them to put away the flashcards and enjoy their babies; babies' brains will take care of themselves.

A parody in the Onion was headlined STUDY REVEALS: BABIES ARE STUPID. According to "research," infants cannot learn to scuba dive or read a map. The joke works because our expectations of babies' intelligence have been inverted--a small sign of the revolution brought about by Spelke's work.

Pinker is a professor of brain and cognitive sciences at M.I.T. and author of Words and Rules, How the Mind Works and The Language Instinct