First, the perceptual motor stage (0 ~ 2 years old)
Children's cognition in the perceptual movement stage has two great achievements:
1. The persistence of the object is obtained. The so-called permanence of an object refers to the consciousness that children are divorced from the perception of the object and still believe that the object continues to exist. That is, when an object disappears from children's field of vision, children get the permanence of the object in about 9 ~ 12 months.
2. Causality formation.
Second, the preoperative stage (2 ~ 7 years old)
Piaget used different forms of operation as a sign of dividing stages. Operation refers to an internalized reversible action, that is, thinking activities that can run in the opposite direction in the mind, or operation refers to an internalized conceptual operation.
Piaget divided the pre-operation stage into two stages: pre-conceptual or symbolic thinking stage (2-4 years old) and intuitive thinking stage (4-7 years old).
The characteristics of children's thinking at this stage are mainly reflected in the following aspects:
1, Early Signal Function: Representation Symbol-Delayed Imitation and Language Symbol
2. animism and egocentrism egocentrism mean that children tend to know things from their own standpoint and viewpoint, rather than from the objective and other people's viewpoints. (Piaget's Three Mountains Experiment)
3. Thinking activities are concrete, and it is impossible to carry out abstract operational thinking. 4. Thinking is irreversible: children can't mentally think about what they see, and they can't recall what things looked like before they changed.
Third, the specific operation stage (7 ~ 12 years old)
It has the following two remarkable features:
1, obtained by conservation, the reversibility of thinking is a sign of conservation and also a sign of specific operation stages. Children can think backwards about the changes they see, compare them before and after, and think about how this change happened. Conservation refers to the characteristic that individuals can realize that the intrinsic properties of objects do not change with the changes of their external forms.
Children first master the conservation of numbers, generally at the age of 6-7, followed by the conservation of matter, which appears at the age of 7-8, while the conservation of geometric weight and length is around 9- 10, and the conservation of volume is generally after1-12.
2. Formation of group structure The group structure is a classification system, which mainly includes cluster-like operation and serialized cluster operation. In the specific operation stage, children's ability to classify and understand concepts has been significantly improved. When solving the classification task of combining two kinds of complex clusters, the specific operation period is different from that of children in the previous operation period, and they can classify according to the complex rules of combining various characteristics of objects.
Although children have achieved many cluster operations in the specific operation stage, they still need the support of specific things at this time, and they can't think about things that don't exist or never happen.
Fourth, the formal operation stage (12~ 15 years old)
As mentioned above, in the specific operation stage, children can only think or calculate with specific things, objects or processes, and cannot use things and processes expressed in language or words as the basis for calculation. For example, Edith, Susan and Lily all have dark hair, and the specific operation stage cannot be judged according to the text description.
When children's intelligence enters the formal operation stage, thinking does not have to start from specific things and processes. We can imagine and think in our minds with words and characters, and reconstruct things and processes to solve problems. Therefore, children can easily answer that Susan's hair is black, without resorting to the specific image of the doll. This kind of operation is called formal operation, which is to get rid of the shackles of specific things, solve problems with words and words, and reconstruct things and processes in your mind.
In addition to using language, children in the formal operation stage can even deduce assumptions and draw conclusions according to concepts and assumptions. Therefore, formal operations are often called hypothetical deductive operations. It is assumed that deductive thinking is the basis of all operational forms, including logic, mathematics, natural science and social science. Therefore, whether a child has the ability of hypothetical reasoning is an extremely important measure to judge his intelligence.
Of course, children in the stage of formal operation can not only carry out hypothetical deductive thinking, Piaget believes that they can also carry out some basic operations needed by all science and technology. These basic operations, in addition to the specific operation stage, also include some basic operations: consider all possibilities; Separate control variables and eliminate all irrelevant factors; Observe the functional relationship between variables and organize the related principles into an organic whole.