Chimerism is what happens when cells from one twin are present in the other. For example, white blood cells with Y chromosomes would be found in the female twin. Vigier et. al, 1989.
Piaget's theory of cognitive development. Piaget's theory of cognitive development is a comprehensive theory about the nature and development of human intelligence. It was first created by the Swiss developmental psychologist Jean Piaget (1896â1980).
Vygotsky's theory is complementary to Bandura's work on social learning and a key component of situated learning theory as well. Because Vygotsky's focus was on cognitive development, it is interesting to compare his views with those a constructivist (Bruner) and a genetic epistemologist (Piaget). Application. This is a general theory of cognitive development.