2. Ausubel's cognitive structure assimilation theory.

Ausubel believes that meaningful learning occurs when students relate the teaching content to their own cognitive structure. The so-called cognitive structure refers to the quantity, clarity and organizational structure of students' existing knowledge, which consists of facts, concepts, propositions and theories that students can recall at present. Therefore, in order to promote the learning of new textbooks, we must first strengthen the concepts related to new textbooks in students' cognitive structure.

From the perspective of teaching, the purpose of studying cognitive structure is to identify and control the variables that affect meaningful acceptance learning. Ausubel believes that we must pay attention to the following three variables: ① Whether the related concepts in students' cognitive structure that can be connected with new textbooks can be used. If these concepts can be used, it will provide necessary fixed points for learning and memorizing new textbooks. (2) What is the difference between these concepts and the new concepts to be learned, that is, to prevent the old and new concepts from being confused and to keep the new concepts as independent entities. (3) Whether the concept of fixed point in cognitive structure is stable and clear. This will not only affect the strength of the fixed point provided by the new textbook, but also affect whether students can distinguish between old and new concepts. The theory of meaningful learning emphasizes that the original concept of appropriateness in cognitive structure plays a decisive role in the learning of new knowledge. This original concept of appropriateness plays a fixed role in new knowledge, so it is called fixed concept or "fixed concept" translation.

It can be seen that whether students have fixed ideas plays an important role in whether learning is meaningful. In Ausubel's view, one of the main reasons for mechanical learning textbooks is to require students to learn new content before they have fixed concepts. Because there are no related concepts in students' cognitive structure that can be linked with the new textbook, the textbook has lost its potential significance.

Ausubel believes that the core of assimilation theory is that whether students can obtain new information mainly depends on the existing concepts in their cognitive structure. Meaningful learning can only happen through the interaction between new information and existing concepts in students' cognitive structure. The result of this interaction leads to the assimilation of the meaning of old and new knowledge.

For example, in lower learning, the interaction between new knowledge (represented by A) and existing concepts in students' cognitive structure (represented by A) not only makes new knowledge gain new meaning (represented by a 1), but also makes existing concepts gain new meaning in the process of reorganization (represented by A 1). That is to say, A is assimilated by A. As a result of the interaction between A and A, both A and A have changed and gained new meanings. More importantly, there is a connection between a 1 and A 1, which is the product of the interaction between old and new knowledge. Together, they constitute a compound meaning (represented by a 1A 1), or a new compound concept. For example, whales have been assimilated into mammals, and the concepts of whales and mammals have also changed.