Jean Piaget is probably the most influential theorist in the cognitive development realm. His work has informed American educational practices since the early 1900s. Another key cognitive theorist in the realm is Lev Vygotsky. Interestingly, Vygotsky and Piaget were contemporaries (both were born in 1896), but for many years, Piagets theory dominated. The fact that Vygotsky died at age 37, while Piaget lived to be 84, might be part of that explanation. But Vygotskys ideas gained traction in the 1980s when educators began to question long held Piagetian ideas. Nevertheless, both theories are important to the study of cognitive development. In your initial post of 300 words minimum,