Jean Piaget was a cognitive constructivism. He studied children as they move thogut different ages and observed they met similar stages of mental cognitive growth at different ages. His view was that children reached the next stage only after the previous stage had been mastered(Cooper, 2009). Piaget's view is that a child develops learning on his own through experiences and motivation through each stage. The child as he goes thorough the stages learns to self -regulate his knowledge. Self -regulation is a basic function of metacognition.
Stages of Cognitive Development:
| Stage             | Age             | Features             | 
|               |               |               | 
| Sensorimotor                stage             | Birth                to 2 years             | Rudimentary                perceptual abilities                         Reflexive movements                         Inability to mentally represent unseen objects                         Non-random movements in response to sensations             | 
  |               |               | 
| Pre-                Operational stage             | 2                to 5 years             | Representational                thought                         Can make mental transformations on ideas/images                         Unstructured flow of thought                         Egocentric thinking *                         Cannot solve conversational problems **                         Difficulty with transitive relationships ***             | 
|               |               |               | 
| Concrete                Operations stage             | 5                to 11 years             | Has                mastered the concept of conservation                         Can take other's perceptual perspectives                         Can perform operations on concrete ideas and objects                         Cannot perform mental operations on abstract or            hypothetical elements                         Difficulty understanding relationships among            relationships             | 
|               |               |               | 
| Formal                Operations stage             | 11                years to adult             | Can                perform all the cognitive abilities described.             | 
|               |               |               | 
|               | Beyond                age 18             | Accumulation                of knowledge and skills and not the acquisition                         of new cognitive abilities             | 
|               |               |               | 
                                                                                                                                        (Cooper, 2009)
The stage of Formal Operational thought is the stage in which a child is involved in thinking about thinking. Which is the definition of metacognition (St. Clair, n.d.). Metacognition begins to develop during this stage and further in life.

 Lev Vygotsky was a social constructivist. Vygotsky agreed with many of Piaget's views but believed that society influenced the development of cognition. Vygotsky believed that a child learned by guidance from adults and peers. Vygotsky's observed that when children are learning something new, the child is unable to preform the task with out guidance. Then they can do it             with the assistance of an adult or an older peer and finally they can do it without assistance. The ZPD (zone of proximal development)             is the stage where they can do it assisted, but not             alone. Thus the teacher often serves to guide a child as they learn something new (Cooper, n.d.).
 
                
 
 
Zone of Proximal Development | 
| Begin of the   Process | Period of   Growth | End of the   Process | 
| What you already know | What you are going to learn | What you will know | 
| Introduction of a concept | Learning the concept | Evaluation of what you have learned | 
| Presentation of a New Tool | Learning to Use the New Tool | Demonstration of the Successful Use of the New   Tool. | 
| Introduction of a New Concept | Learning to Use the New Concept | Successful Application of the New   Concept | 
                                                                                                                                        (St. Clair, n.d.)
 "What is important about the ZDP is that when a mentor or adult assist a child in learning, he is engaged in a metacognitive act. The mentor or adult is teaching the child how to think about thinking" ( St. Clair, n.d.).  The child  develops metacognitive skills that he learns from his mentors. Vygotsky view is that learning does not occur on it's own it is taught through socialization.
 
 
  John Flavell is considered the founding researcher in metacognition. He based many of his insights on Piaget's theories (Cooper, n.d.). "The term "metacognition" is often associated with John Flavell,(1979)"( Livingston, 1997).  "According to Flavell(1997, 1987), metacognition consists of both metacognitive knowledge and metacognitive experience or regulation(Livingston,1997).