Interest is a characteristic that makes people feel happy, interesting and attractive. If knowledge makes people feel lively and interesting, it will attract people, make people interested in learning, engage in learning happily and get good grades, so it can be said that "fun makes learning".

When interest does not point to the object of knowledge, but to some kind of activity, this motivation is called hobby, such as sports, painting, calligraphy and so on. Interests and hobbies are associated with people's positive emotional experience. When people engage in certain activities and acquire certain knowledge with great interest, they often experience positive emotions such as comfort and satisfaction.

People's cognitive interest appeared very early in individual development, initially manifested as individual's exploration of the environment. After a baby is born, he will react with surprise and excitement to new things that appear in the environment. Older children usually look, touch, shake, break or even destroy new toys. It is on the basis of the directional inquiry activities in the early life of individuals that people's interests in things and activities are gradually formed.