In Vygotsky's world, a child was not a product of the environment, instead the child interacts with the environment by making choices, which moderate or influence the environment's effect on the child . Lev Vygotsky's developmental stages were not defined by age or biology, the basis behind his theory was the understanding of a child's social and cultural experiences and how these influence the child's development. A philosophy of Vygotsky's theory was the zone of proximal development (ZPD), this is the difference between what a child is able to solve on his own based on the stage of cognitive development and what a child can learn with help or another person's experience. Vygotsky believes that the skill of knowledge comes from the mastery of new social situations in which learning is shared with others. He also believed that experiences should be shared in social contexts and placed great emphasis on the quality of teamwork within the process of cognitive development. Within group work, children's language is encouraged to develop, through conversation, questions and sharing cognitive content with their peers. Vygotsky believed that "social interaction allows the child to develop the intellectual abilities necessary for reasoning and logical thinking." (Grossman, S. 2008) Through language and communication, children learn to evaluate the world and modify their actions accordingly. Adults play an active role in enhancing a child's cognitive development, aiding the child's efforts and enabling him or her to gain skills, knowledge and confidence.” (Grossman, S. 2008) As children gain skills through supported learning, “adults slowly decrease their support until children are able to work independently.” (Grossman, S. 2008) With......in the center of the sheet......children. Each of them is of great importance for developing an overview of the evolutionary concept of human development. Children's cognitive development has an intimate relationship with the emotional, social and biological developments they face. All these aspects are involved in the development of intelligence in children. To conclude, the contrasting but significant work of these theorists illustrates how learning theories developed more than a century ago are still very influential in attitudes toward early childhood education. While there may be differences of opinion among theorists as to which learning method is most effective, many of the insights provided by Piaget and Vygotsky all have substantial elements of reasoning. in the modern world today and will continue to have significance in studies of child cognitive development for years to come.