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 ...

children enter the preoperational stage at around two years old Despite being over 70 years old, Piaget's theory is "still one of the prevailing theories in terms of cognitive development," Dr Sam ...

Jean Piaget's ideas about child development continue ... but go through a series of qualitatively distinct stages throughout ...