According to Piaget's theory, cognitive development takes place in four separate stages and each stage progresses onto being more refined and conceptual levels of thought. Sensorimotor, the first stage (birth to 24 months) is characterized by knowledge being achieved mainly through sensory impressions and motor action. At the end of this stage, the child will have a little understanding outside what can be sensed. The subsequent stage is the preoperational stage (2 to 7 years) describes how child shifts from sensory testing to the progression of language and using of symbols. The basic characteristics of the stage are reading and a quick increase in vocabulary. The third stage is concrete operational (7 to 11 years) shows significant developments in perception and in the last phase known as the formal operational (11 to adulthood) explains the child's developing the skill to think about hypothetical conditions and reflect abstractly.
Lev'Vygotsky, another renowned theorist, proposed the Sociocultural Theory of Development which suggested that children learn through socially interacting with their surrounding culture and communicate with others to learn the cultural values of the society through dialogue.
Children progress in the direction of more individualized thought process during these social interactions. The co-constructed development incorporates individuals interacting through shared activities. Once the child is assisted in this process, he or she may be able to use enhanced strategies in the future if a familiar situation arises. This leads to internalization, which further results in the child's independent thought process.
There are essential similarities between the natures of development of intelligence in children. This is particularly obvious in their views on the stage-related development process of cognitive abilities. Vygotsky is well known on his position on the importance of social factors in development. Piaget stressed the vital role of social factors in the building of knowledge. According to Piaget, social interaction is necessary in order to develop logic. Furthermore, both Vygotsky and Piaget agreed that it is the development of the individual which ultimately takes place. They also stated that internalization is not a process of copying material from the environment but is a transformative process.
Piaget investigated the fundamental mechanisms in the individual constructing its thoughts, while Vygotsky dealt with socially developed mechanisms for constructing language meaning and learning. But both of them relate mental processes to the generative constructions of systems that maintain development, that is, in culture or in the individual interacting with its environment. In Vygotsky's opinion language is makes human species humanized and makes human thought a part of culture. On the other hand, language for Paiget is one of the five behavior patterns that manifest representational intelligence in children. Paiget's theory of intelligence is based on biological factors, but it also implies social dimensions as well. The