Stage theories are based on the idea that elements in systems move through a pattern of distinct stages over time and that these stages can be described based on their distinguishing characteristics.
Piaget's theory goes through four stages: Sensorimotor: (birth to 2 years), Preoperations: (2 to 7 years), Concrete operations: (7 to 11 years), and Formal Operations: (11 to 16 years). Each stage has at least two substages, usually call early and fully. Also see Theory of cognitive development.
Sensorimotor Stage (birth to 2 years) A child comes into the world knowing almost nothing, but they have the potential that comes in the form of:
Infants use these potentials to explore and gain an understanding about themselves and the environment. They have a lack of object permanence, which means they have little or not ability to conceive things as existing outside their immediate vicinity. For example. When you place a barrier, such as a piece of wood in front of an object an infant will believe that the object is non existent.
Preoperational Stage (2 to 7 years) Preoperational intelligence means the young child is capable of mental representations, but does not have a system for organising this thinking (intuitive rather than logical thought). The child is egocentric – which is they have problems distinguishing from their own perceptions and perceptions of others. A classic example is, a preoperational child will cover their eyes so they can’t see someone and think that that person can’t see them either.
The child also has ridged thinking, which involves the following.
Concrete Operations (7 to 11 years)
The concrete operational child will overcome the aspects of rigidity apparent in a preoperational child. These are:
The tasks of concrete operations are:
It is important to realise that operations and conservations don’t develop at the same time. They develop gradually and are not an ‘all or nothing’ phenomenon. For example, the first to develop is number conservation followed by mass conservation, area conservation, liquid conservation and finally solid volume conservation. Thinking is not abstract. It is limited to concrete phenomena and the child’s own past experiences.
Formal operations (11 to 16 years)
Juan Pascaual-Leone founded neoPiagetian stage theory when he pointed out to Piaget that all the half stages were stages also. Since that time there have been many stage theories proposed. Only the ones that cover at least infancy thought adulthood will be mentioned here. These inlcude Kurt W. Fischer's Skill Theory and Michael Commons and Francis Asbury Richards' Model of hierarchical complexity. There are now 15 stages, with 4 being added beyond Formal and one added between the beginning of preoperations and preoperations. Most stage sequences map onto one another. PostPiagetian stages are devoid of content and context and are therefore very powerful and general.