Jean Piaget (1896-1980 ... the toy still existed. Piaget found four major developmental stages (with many subdivisions). For the first year and a half or two years of life, infants are only ...

Jean Piaget's ideas about child development continue ... He proposed that children pass through four main stages: the sensorimotor stage, the preoperational stage, the concrete operational stage ...

"At four or five months ... key part of the preoperational stage and, as a result, you might see them taking part in pretend play. Image caption, According to Piaget, children enter the ...