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).
Vygotskyâs theory is called a socio-cultural theory of cognitive development. He believed that children, in different cultures, learn ways of thinking that are necessary to live in their own culture and community. Children in different cultures develop unique cognitive strengths.