With the passage of time, behavioral finance will not be regarded as a trivial branch of finance, but will gradually become the central pillar of serious financial theory. It can be seen that the importance of behavioral finance and the psychological judgment bias in investors' psychological investment decisions are not divided into typical bias and conservative bias. Typical deviation leads investors to pay too much attention to recent data and ignore the collective characteristics that produce these data; Defending the deviation makes it impossible for investors to correct their models in time according to the changes in the situation. As a new field and an important research direction of modern finance, finance is not a complete denial of traditional finance. Simply put, the difference between investors and non-information traders is that behavioral finance has added psychological research results, revised and supplemented the traditional financial theory, and broke through the traditional optimal decision-making model. People who make decisions on investors and non-information traders will not have judgment bias, but the stock price is determined by information traders. There are two kinds of biases in information traders: overconfidence bias and self-attribution bias. Overconfidence leads them to exaggerate the decision-making weight of private information on stock value, and self-attribution leads them to reduce the research direction of public information countermeasures from "how to do it" to "how to do it internationally", which is more in line with the actual situation. However, the development of financial theory is still in the primary stage, and the emergence of main theories and models is still scattered, which has not yet formed a unified theoretical system like traditional financial theory. On the basis of existing theories and models, the decision weight of stock value is integrated. When public information is inconsistent with private information, overreaction to private information and underreaction to public information lead to the persistence of short-term stock price trend and long-term stock price correction, because public information will eventually overcome behavioral deviation. 19 9 9, og and Se Hn tn established the H i s model, also known as the unified theoretical model. The model divides traders in the market into message observers and momentum traders. News observers use their own observation and analysis to predict the stock price. Private information is spread among news observers, and its limitation lies in the certainty of investment. Momentum traders try to use arbitrage strategy to develop a unified theoretical system of behavioral finance, which is an urgent problem to be solved.
Behavioral finance developed when some abnormal phenomena appeared in traditional financial theory. Behavioral finance believes that human beings have certain rationality, but not all human behaviors are rational. In the financial market and financial activities, the rational person and the effective equilibrium market, which are assumed by the traditional theory to completely pursue the maximization of economic utility, cannot be verified by practice. Behavioral finance, based on the basic premise of bounded rationality and limited control of human behavior, injects human emotional factors and psychological activities into the investment decision-making process, and thinks that these factors play an important role in the human decision-making process. On this basis, it has become the existence value of behavioral finance to establish a set of theories that can be tested by empirical research and describe human decision-making and market activities under uncertainty and securities price determination.
Through the above analysis, we can see that behavioral finance is very different from traditional financial theory, but at the same time, we can't deny that behavioral finance was cultivated on the terrace of traditional financial theory. It does not try to overthrow the previous theories, but develops the research ideas and methods of finance, so as to improve and revise the financial theory and make it more perfect and effective. Behavioral finance and traditional financial theory are one-sided. We should relax and revise some assumptions of the traditional financial theory on the basis of it, and make it a more perfect and reasonable theory, which can better explain some financial phenomena.
At the same time, although behavioral finance has made some achievements, on the whole, behavioral finance has not yet formed a systematic theory. Many scholars talk about Kan Kan, drawing their own pictures, the theory is scattered, and the tension of the theory is obviously insufficient. Therefore, we should combine some existing theories in behavioral finance on the basis of traditional theories to further develop and improve this theory.
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