Based on these two deviations, BSV model explains how the investor's decision-making model causes the market price to deviate from the efficient market hypothesis. Overreaction and underreaction are two situations in which investors react to market information. In the process of investment decision-making, when investors are involved in investment behavior related to statistical data, people's psychology will have a process of distorted reasoning. The typicality of events will lead to overreaction, while "anchoring" will lead to underreaction. The typicality of events means that people usually classify things quickly. People's brains usually classify things with the same surface characteristics but different substance. When the typicality of events helps people to sort out and process a large amount of data and materials, it will lead investors to overreact to some outdated information. For example, the soybean futures market analyzes seasonal factors from historical data. According to the experience of "when the old contract is terminated, it always falls in the end" (such as S2 1 1, S30 1), it is concluded that the futures price should eventually fall. However, when the fundamentals change greatly, people often ignore the new changes of the fundamentals because of overreaction to the above concepts, which leads to price distortion (for example, the prices of S2 1 1 and S30 1 have been suppressed for a long time). However, it does not mean that investors will not change their views. With the passage of time, this fundamental change will continue, and investors will eventually change their wrong views.