The so-called schema refers to the representation and storage of knowledge organized around a certain theme. A person has to learn and master a lot of knowledge in his life. This knowledge is not stored in people's brains in disorder, but related to a certain theme to form a certain knowledge unit, which is schema. For example, when we see a picture of an animal, we can quickly remember its name, temperament, living habits and many other knowledge about animals. This shows that the appearance characteristics of animals are related to their names, temperament, living habits and other related knowledge and stored in the human brain. Therefore, schema is actually a cognitive model about knowledge. Schema theory studies how knowledge is represented and how this knowledge representation is beneficial to the application of knowledge in its unique way.

The word schema has appeared in Kant's philosophical works. In the study of modern psychology, Gestalt psychology first attaches great importance to schema in theory. Piaget, a famous Swiss psychologist and educator, also attached great importance to the concept of schema. He believes that "schema refers to the structure or organization of action". Modern schema theory was developed after information science and computer science went deep into the field of psychology in the late 1970s, which made profound changes in psychology's research on human cognition. To sum up, modern schema theory mainly has the following points:

1. Schema describes knowledge with a certain degree of generalization rather than definition. In other words, schema not only describes the necessary features of things, but also contains their unnecessary features. The knowledge described by schema is composed of one part or several parts in a certain way, and the components are called variables or slots. For example, animal schema includes skin, mobility, eating and breathing air; Birds have wings, feathers, flying and so on. In short, a symbol, an object, etc. Can be seen as a schema.

2. Schemas can be divided into simple and complex, abstract and concrete, advanced and low. A simple pattern can have only one character, and a complex pattern can be composed of several sub-patterns. Abstract schema is a schema about ideology and cultural concepts, while concrete schema includes life experiences and the characteristics of things. The so-called high-level mode and low-level mode refer to the hierarchical or subordinate relationship between modes. For example, the animal schema and bird schema mentioned above constitute a relatively complex schema. Birds belong to animals. For birds, the schema of animals is higher or higher, while that of birds is lower or lower.

3. Schema is not a simple mechanical addition of all parts, but an organic whole composed of all parts according to certain laws. Every part of the schema, that is, variables, are constants and variables; When some variables take certain values, the values of other variables are also constrained. The process of schema processing is realized by fitting, optimizing and evaluating the processed information. For some information processing, it is even necessary to compare and evaluate several modes before making a decision.

4. Schema is formed through "assimilation" and "adaptation" on the basis of the mutual connection between old knowledge and new information of past experience, and it is an active organization of past experience. Schema does not passively accept information, but actively associates new information with the old knowledge represented by schema. Each schema is changed through assimilation and coordination in the process of development. After assimilation, coordination and balance, the low-level schema gradually develops into the high-level schema. "Assimilation" and "Adaptation" are two important concepts in Piaget's schema theory. "Assimilation" is to incorporate external information into the existing schema, so that the schema is constantly expanding. "Adaptation" means that when the environment changes, the original schema can no longer assimilate new information, and a new schema can only be established through adjustment and transformation.