The following has been adapted from the Wikipedia: Jean Piaget and his theories website.
Piaget served as professor of psychology at the University of Geneva from 1929 to 1975 and is best known for reorganizing cognitive development theory into a series of stages, expanding on earlier work from James Mark Baldwin: four
levels of development corresponding roughly to (1) infancy, (2) pre-school, (3) childhood, and (4) adolescence. Each stage is characterized by a general cognitive structure that affects all of the child's thinking (a structuralist view influenced by philosopher
Immanuel Kant). Each stage represents the child's understanding of reality during that period, and each but the last is an inadequate approximation of reality. Development from one stage to the next is thus caused by the accumulation of errors in the
child's understanding of the environment; this accumulation eventually causes such a degree of cognitive disequilibrium that thought structures require reorganizing.
The four development stages are described in Piaget's theory as
Sensorimotor stage: from birth to age 2 years (children experience the world through movement and senses and learn object permanence)
Preoperational stage: from ages 2 to 7 (acquisition of motor skills)
Concrete operational stage: from ages 7 to 11 (children begin to think logically about concrete events)
Formal operational stage: after age 11 (development of abstract reasoning).
These chronological periods are approximate, and in light of the fact that studies have demonstrated great variation between children, cannot be seen as rigid norms. Furthermore, these stages occur at different ages, depending upon
the domain of knowledge under consideration. The ages normally given for the stages, then, reflect when each stage tends to predominate, even though one might elicit examples of two, three, or even all four stages of thinking at the same time from one
individual, depending upon the domain of knowledge and the means used to elicit it.
Despite this, though, the principle holds that within a domain of knowledge, the stages usually occur in the same chronological order. Thus, there is a somewhat subtler reality behind the normal characterization of the stages as described
The reason for the invariability of sequence derives from the idea that knowledge is not simply acquired from outside the individual, but it is constructed from within. This idea has been extremely influential in pedagogy, and is usually
Once knowledge is constructed internally, it is then tested against reality the same way a scientist tests the validity of hypotheses. Like a scientist, the individual learner may discard, modify, or reconstruct knowledge based on its utility in the real
world. Much of this construction (and later reconstruction) is in fact done subconsciously.
Therefore, Piaget's four stages actually reflect four types of thought structures. The chronological sequence is inevitable, then, because one structure may be necessary in order to construct the next level, which is simpler, more generalizable,
and more powerful. It's a little like saying that you need to form metal into parts in order to build machines, and then coordinate machines in order to build a factory.
Piaget's view of the child's mind
Piaget viewed children as little philosophers, which he called tiny thought-sacks and scientists building their own individual theories of knowledge. Some people have used his ideas to focus on what children cannot do. Piaget, however, used their problem
areas to help understand their cognitive growth and development.
Piaget provided no concise (or clear) description of the development process as a whole. Broadly speaking it consisted of a cycle:
The child performs an action which has an effect on or organizes objects, and the child is able to note the characteristics of the action and its effects.
Through repeated actions, perhaps with variations or in different contexts or on different kinds of object, the child is able to differentiate and integrate its elements and effects. This is the process of reflecting abstraction.
At the same time, the child is able to identify the properties of objects by the way different kinds of action affect them. This is the process of empirical abstraction.
By repeating this process across a wide range of objects and actions, the child establishes a new level of knowledge and insight. This is the process of forming a new cognitive stage. This dual process allows the child to construct
new ways of dealing with objects and new knowledge about objects themselves.
However, once the child has constructed these new kinds of knowledge, he or she starts to use them to create still more complex objects and to carry out still more complex actions. As a result, the child starts to recognize still more
complex patterns and to construct still more complex objects. Thus a new stage begins, which will only be completed when all the child’s activity and experience have been re-organized on this still higher level.
This process is not wholly gradual, however. Once a new level of organization, knowledge and insight proves to be effective, it will quickly be generalized to other areas. As a result, transitions between stages tend to be rapid and
radical, and the bulk of the time spent in a new stage consists of refining this new cognitive level. When the knowledge that has been gained at one stage of study and experience leads rapidly and radically to a new higher stage of insight, a "gestalt"
is said to have occurred.
It is because this process takes this dialectical form, in which each new stage is created through the further differentiation, integration, and synthesis of new structures out of the old, that the sequence of cognitive stages are logically
necessary rather than simply empirically correct. Each new stage emerges only because the child can take for granted the achievements of its predecessors, and yet there are still more sophisticated forms of knowledge and action that are capable of being
Because it covers both how we gain knowledge about objects and our reflections on our own actions, Piaget’s model of development explains a number of features of human knowledge that had never previously been accounted for. For
example, by showing how children progressively enrich their understanding of things by acting on and reflecting on the effects of their own previous knowledge, they are able to organize their knowledge in increasingly complex structures. Thus, once a
young child can consistently and accurately recognize different kinds of animals, he or she then acquires the ability to organize the different kinds into higher groupings such as ‘birds’,
‘fish’, and so on. This is significant because they are now able to know things about a new animal simply on the basis of the fact that it is a bird – for example, that it will lay eggs.
At the same time, by reflecting on their own actions, the child develops an increasingly sophisticated awareness of the ‘rules’
that govern in various ways. For example, it is by this route that Piaget explains this child’s growing awareness of notions such as ‘right’, ‘valid’, ‘necessary’,
‘proper’, and so on. In other words, it is through the process of objectification, reflection and abstraction that the child constructs the principles on which action is not only effective or correct but also justified.
One of Piaget’s most famous studies focused purely on the discriminative abilities of children between the ages of two and a half years old, and four and a half years old. He began the study by taking children of different ages
and placing two lines of M & M’s, one with the M & M’s in a line spread further apart, and one with the same number of M & M’s in a line placed more closely together. He found that, “Children between 2 years, 6 months
old and 3 years, 2 months old correctly discriminate the relative number of objects in two rows; between 3 years, 2 months and 4 years, 6 months they indicate a longer row with fewer objects to have "more"; after 4 years, 6 months they again
discriminate correctly”. Initially younger children were not studied, because if at four years old a child couldn’t conserve quantity, how could a child that is younger? The results show however that children that are younger than three
years and two months have quantity conservation, but as they get older they lose this quality, and don’t recover it until four and a half years old. This attribute may be lost due to a temporary inability to solve because of an overdependence on
perceptual strategies, which correlates more candy with a longer line of candy, or due to the inability for a four year old to reverse situations.
By the end of this experiment several results were found. First, younger children have a discriminative ability that shows the logical capacity for cognitive operations exists earlier than acknowledged. This study also reveals that
young children can be equipped with certain qualities for cognitive operations, depending on how logical the structure of the task is. Research also shows that children develop explicit understanding at age 5 and as a result, the child will count the
& M’s to decide which has more. Finally the study found that overall quantity conservation is not a basic characteristic of man’s native inheritance.