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).
Cognitive theory of Jean Piaget four stages. Cognitive theory of Jean Piaget includes four stages of development that children move through during which the explanatory behaviors of infants transform into the abstract, logical intelligence of adulthood.