body of evidence that the elementary information processes used by the human brain in thinking are highly similar to a subset of the elementary information processes that are incorporated in the instruction codes of ...
computers'. In fact, cognitive psychologists have used the metaphor of the computer to compare with cognitive processes, highlighting at the same time the objectivity of their research (Tonnessen, 1999).
component. In developing his theory incorporating the two components, Piaget emphasized that the child is actively involved in development. In Piagetian theory the child's mind is not a blank slate (Elkind 1971). On the contrary, the child has a multitude of ideas about the world, which may be quite different from an adult's understanding of it. The child in the course of his or her education is always learning and unlearning ideas about the world such as the concepts of space, time, quantity and number.
Finally, 'the child is by nature a knowing creature' and as such 'the child is trying to construct a world view of his own, and is limited only by his abil- ities and experience' (Elkind, 1971: 108).
In the stage-independent component of his theory, Piaget addressed the issue of how cognitive development proceeds. He listed four factors to account for cognitive development: maturation or organic growth, experi- ence, social transmission and equilibration (Honstead, 1968). Further details of these are given below.
1. Maturation. From a biological perspective, the developing child is maturing. At birth the immaturity of the infant's brain is a factor limit- ing cognition, but brain development (most rapid before birth) pro- ceeds rapidly in the first two years after birth and continues to some extent for much longer. Understanding of the links between brain development and cognition has begun only recently (Fischer, 1987).
2. Experience. Piaget has argued that experience is of two kinds:
(a) direct physical experience, such as playing with water and generally using the five senses to experience the world
(b) mathematical experience, which occurs when the child reflects on the structure of experience and particularly on its logical and mathematical structure; according to Piaget and Inhelder (1969), logico-mathematical experience comes from the child's acting on the world rather than from the experience itself.
3. Social transmission. The concept of social transmission is the least developed part of Piaget's model: 'Piaget placed his main emphasis on the dialectic between the child and the physical world, but included social interaction as a motivator of development, particularly through conflict of ideas between peers' (Meadows, 1986: 108). That is, in the process of interacting with other children or adults, a child is chal- lenged and forced to 'decentre' in order to deal with the multitude of conflicting ideas with which she or he is presented.
4. Equilibration. This is probably the most basic of the four factors:
It is the process of achieving equilibrium, of finding a balance between those things that were previously understood and those that are yet to be understood. A child, encountering something new to him, actively works at relating it to something he knows. As the new object in its turn becomes familiar to him, he reaches a
new level of equilibrium. He has thus gone through the process of equilibration of self regulation.
(Honstead, 1968: 135) Piaget's theory is well known as a 'stage' theory of development. Four criteria for such theories were described by Inhelder (1975):
1. a period of formation and progressive organization of mental operations 2. the progressive hierarchical development of one stage upon another 3. relative similarity on the attainment of each stage
4. a directional and hierarchical nature.
As our readers will doubtless be aware, the stage-dependent component of Piaget's theory is made up of four major stages (as described below):
sensori-motor; pre-operational; concrete operational; and formal opera- tional. Each of Piaget's stages is identified in terms of the child's principal method of knowing.
1. Sensori-motor period (0-2 years). The child's primary method of knowing during the sensori-motor period is through the actions he or she performs on the world in terms of the five senses. Initially the child's behaviour is governed by simple reflexes but this situation changes rapidly during the next few years.
2. Pre-operational period (3-7 years). The emergence of language, modelling and memory are key features of the pre-operational period. It is the time when, according to McGurk (1975: 36-7), 'the child's inter- nal, cognitive representation of the external world is gradually develop- ing and differentiating but many serious limitations are also in evidence'. The child's thinking is dominated by perception rather than concepts (McGurk, 1975). For example, the child makes judgements in terms of how things look to her or him, not how they actually are. If shown two balls of clay of equal size and weight, and if one is then squeezed into a sausage shape and the child is asked if there is as much clay in the sausage as the ball, he or she is likely to say that the sausage has more clay because it looks longer. The child's acquisition of lan- guage signals the beginning of symbolic thought. Thus a child sees a hairy animal with four legs, a tail, ears and making a barking sound, and calls the animal a dog. The animal is the reality; the word dog is the symbol. Egocentrism is another element of the child's thinking; thus a girl may tell you she has a sister but deny that her sister has a sister.
3. Concrete operations period (7-11 years). During this period, children's thinking attains greater flexibility:
He can understand, easily and naturally, the concept of conserva- tion. 'Grouping' of ideas thus comes about; logical deductive reasoning is possible. However, concrete operations are limited in
that they are capable of operational groupings only with concrete objects such as blocks, sticks, clay, liquids and marbles. Logical thought does not yet extend to verbal stimuli.
(Honstead, 1968: 139) 4. Formal operations period (11+ years). In Piaget's theory this is the
final period of cognitive development. McGurk (1975: 39) notes that 'The hallmark of this stage is the child's ability to reason abstractly without relying upon concrete situations or events'.
Piaget's view of cognitive development is that in the process of develop- ment the individual moves from a less to a more mature level of function- ing. The child is actively involved in pursuing information and attempting to understand the world. Piaget's theory has been labelled 'constructivist' (Gelcer and Schwartzbein, 1989) inasmuch as the child actively constructs the external world in acting upon it. Such a view contrasts with behaviour- al theories that emphasize the passivity of the child who is acted upon and shaped by the external world. From a biological perspective, though, Piaget viewed development as progressive and directional. The invariant feature of his theory emphasized a stage-like development, in which the child's manner of thinking at one level is qualitatively different from the way of thinking at a later stage.