Both Vygotsky and Piaget talked about the cognitive development of human beings starting from their early stage of life. Cognitive development can be defined as the process of gathering thoughts from the early stage of one's life to adulthood, as a result of this, these thoughts have formed our language, thinking, mental imagery, decision making and problems solving skills. Both Vygotsky and Piaget came up with theories that explained the cognitive development of human beings.
Piaget explained that cognitive development in human is as a result of our interactions with the environment and that learning can only take place after development has occurred in a man. Vygotsky explained that, learning can only take place through experiences, and that, development can only happen in a man after learning has taken place. Piaget explained that development in human beings occurs in four phases i.e the sensorimotor, egocentric, concrete operational stage and the formal operational stage. While Vygotsky does not believe in that theory.