Peter Bryant has conducted important work in developmental psychology. Working with both intellectually disabled children and those with normal development, he has developed and provided experimental evidence for a theory linking children’s perception and their intellectual development. He has demonstrated that children’s logical abilities vastly exceed the estimates made by Jean Piaget, and was the first to show that preverbal infants can link visual with tactual perception. He has developed a method for testing causal hypotheses about development by combining longitudinal prediction with intervention, and has established a causal link between children’s early phonological skills, in particular their sensitivity to rhyme, and their later success in reading. He has also shown that these early phonological skills depend on early learning at home.