The interesting thing is that even quite tiny children, just beginning to say their first words, already seem to be influenced by what the people around them are talking about. And, of course, the parents are exercising this influence completely unconsciously, just by talking to their babies.

Just as it’s important to infer the nature of other people’s minds in order to survive, it’s also important to infer the nature of the physical world.

It was as if the Korean-speaking children paid more attention to how their actions influenced the world, while the English-speaking children paid more attention to how objects fit into different categories. The likeliest explanation for this is that the children were influenced by what the grown-ups around them said, which in turn was shaped by the

Just as Piaget saw that learning was innate, Vygotsky saw that culture was natural.

Trying to understand human nature is part of human nature. Developmental scientists are themselves engaged in the same enterprise and use the same cognitive tools as the babies they study. The scientist peering into the crib, looking for answers to some of the deepest questions about how minds and the world and language work, sees the scientist

Like disappearance and causality, categorization seems to be a particularly important problem for babies in the first three years. Even very young infants already can discriminate between different objects and make generalizations about them in some ways. We saw that babies will get bored if they are shown a succession of similar things and perk up

The Big Idea, the conceptual breakthrough of the last thirty years of psychology, is that the brain is a kind of computer. That’s the basis of the new field of cognitive science. Of course, we don’t know just what kind of computer the brain is. Certainly it’s very different from any of the actual computers we have now.

Studying babies makes us realize that the biological computers on this planet differ from the man-made computers in this regard, as well. They don’t just compute, learn, reason, and know. They are driven to do all these things and are designed to take intense pleasure in doing so.

Piaget wanted to explain the classical philosophical problems of knowledge. But unlike earlier philosophers he wanted an explanation that would be linked to biology.