The fundamental question in development is how a child comes to understand reality so as to be able to deal effectively in a world of persons, objects, and events. Language is a part of that reality, and this chapter is about the developing cognitive abilities in infancy that bring the infant to the threshold of language at the end of the first year. The emphasis here is on how an infant comes to know about the physical world – a world of objects. How infants learn about persons and a world of social connectedness will be taken up when we turn to development of the expressive infant, in Chapter 4.

Over the years, two important influences on my thinking about cognitive development in infancy have been Jean Piaget and J. J. Gibson. I am aware that their respective theories are not often juxtaposed in this way; in fact, the followers of each have more often used the other's theory as a starting point of disagreement. For example,