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下面为大家整理一篇优秀的assignment代写范文- Heterogeneous expectations，供大家参考学习，这篇论文讨论了异质预期。异质预期，指的是不同的主体因信息的不对或由于认知局限，或使用的预测模型不同等而形成不同的预期，是一个与理性预期相对的新经济学范畴。除了信息、初始认知外，学习是影响异质预期形成的一个重要因素。在存在异质预期的环境中，经济结果取决于所有参与者的预期。

Heterogeneous expectation refers to the different expectations formed by different subjects due to incomplete information, asymmetry, cognitive limitations, or different prediction models used. It is a new economic category that is opposite to rational expectation. In addition to information and initial cognition, learning is an important factor influencing the formation of heterogeneous anticipation. In environments with heterogeneous expectations, economic outcomes depend on the expectations of all participants. Compared with rational expectations, heterogeneous expectations are a more complex transmission mechanism, which will strengthen and amplify the underlying transmission mechanism of the economy, breed economic fluctuations, and increase the durability of inflation. Expected heterogeneity enhances the role of monetary policy, and we should give full play to the stable function of monetary policy.

Expectations are an integral part of economic activity. Economic subject in a consumption investment decision some key variables that must be expected when these expectations is a view of the future, on the basis of faith, and faith is the result of the understanding of reality, is a driving force of each economy, finally these has the qualities of psychological factors affecting the economic and social product service demand and investment will, produce material results. An important feature of expectation is its predicted self-fulfillment. Under the support of belief, expectation dominates people's behavior, and the change of behavior will promote the realization of the expected result, thus confirming the expectation and strengthening the belief as the basis of expectation. So in extreme cases, expectations can have a very powerful effect on the overall performance of the economy, either destroying a healthy economy or maintaining a deteriorating economy.

As a result of the anticipated impact, economic society is considered to be an area of "material and transcendental intersection". The research of economics on expectation is also deepening, including many aspects such as how the expectation is formed and how it changes. It is found that the formation of expectations is a process, and the economic system, especially the monetary system, depends on each other strategically. Contemporary monetary economics puts forward the thought of heterogeneous expectation, believing that under heterogeneous expectation, one of the main tasks of monetary policy is to manage expectation.

The theory of expectations has gone through the stages of static expectations, extrapolated expectations, adaptive expectations and rational expectations. In the 1970s, the rational expectation hypothesis came into being, which has established the position of the expectation theory in macroeconomics, and it has occupied the dominant position of the expected formation paradigm.

The rational expectations hypothesis holds that expectations for economic variables are equal to the best predictions made using all available information. In other words, the subject USES the mathematical expectation formula to form the expectation, and assumes that the expected value of the period t+1 is consistent with the actual value of the period t+1. Therefore, in modeling associated with it, economists generally assume that the subject has complete knowledge of the real random process of the variables to be predicted. Rational expectations provide an elegant and powerful framework that has long dominated thinking about the dynamic structure of the economy and the evaluation of econometric policies. According to the rational expectation hypothesis, most studies involving dynamic macroeconomic models involve rational expectation, assuming that the economic subject's expectation is homogeneous.

Although the rational expectation category fundamentally corrects the deviation of the classical expectation theory which ignores the current information and puts forward the principle that the subject will effectively use all available information in the formation of the expectation, it overdoes it and goes to the extreme in some aspects. The limitations of information processing and cognition are not recognized. "The rational expectations model gives much more knowledge to the subject within the model than the econometrician, the econometrician faces problems of calculation and inference, and the subject in the model tries to solve these problems." It can be seen that "rational expectation" implies strong information assumption, is a special expectation, and is the "super-intelligent economic man expectation", including the standard assumptions of complete rationality, limited uncertainty, homogeneous information and common knowledge.

In addition to information, beliefs, cognition, and learning also affect the formation of expectations. The rationality and irrationality of economic man, the uncertainty of environment, the finiteness of knowledge and information constitute the main problems of the contemporary theoretical research on expectations.

Any form of anticipation is a learning mechanism. Learning has been a topic of discussion in the field since the rational expectations revolution swept through macroeconomics. In recent years, the development of evolutionary game theory and game learning theory has accelerated the spread of heterogeneous anticipation in the field of economics.

Deductive learning takes place in psychological time and describes the reasoning process. Because the reasoning process can be instantaneous, the immediate coordination problem of deductive and stable rational expectation equilibrium is generated. On the contrary, adaptive learning refers to the subject learning from the past experience, constantly improving the knowledge, correcting the mistakes made in the past in the expectation of economic activities, and updating the prediction. This learning method is carried out in actual time. The subject has prediction rules, and the rules are updated according to the prediction error. Generally, it is assumed that the parameter estimates are updated according to the least square method or other statistical methods.

In the stochastic framework, least square method and similar learning rules are the most widely used adaptive learning rules. It Is found that under the standard adaptive learning rule, from the static solution of many standard models, the economy will converge to REE, such as the inflation model of Cagan, the is-lm - PC model of Sar - gent-wallace, the Samuelson iterative model, and the actual business cycle model.

Evolutionary learning, in which the subject USES genetic factors to update beliefs that use evolutionary principles to produce beliefs that are inefficient, is replaced by beliefs that are efficient. Subjects try different beliefs, either a synthesis of their own beliefs with other subjects, called "crossing", or just random changes in beliefs, called "mutations". According to a new set of beliefs, the subject makes new decisions, and new results are produced. Gene method emphasizes the mode of transmission of information in economy and the nature of information transmission is based on the assumed attribute of gene factors. It means that learning dynamics, as a whole, describes searching for equilibrium from the initial almost arbitrary behavior of the subject, finding "good" solutions to complex problems without knowing the optimal solution.

In reality, most learning comes not from any kind of statistical regression, but from the spread of information between people. Important economic judgements spread from person to person, often allowing different people in a group to develop different beliefs. The initial belief of the subject is different, that is, the belief is initially heterogeneous, and it will imitate the people around and other subjects to update the belief. Therefore, evolutionary learning is also called social learning. In evolutionary learning, subjects can learn from others, while in all adaptive heterogeneous learning models, subjects update their beliefs without knowing what others are doing or how they are doing. Accordingly, for learning REE, the social aspect is important.

How do expectations come about? In the early stage of macro-econometric modelling, expectations are modeled as simple extrapolations of recent experiences, and then, in the "rational expectations" revolution, they are modeled as accurate predictions of the future economic environment. Now, economists' understanding of how expectations are formed has changed dramatically, modeling expectations as the result of a learning process that is well-informed intellectual activity that is not always correct, and that may take some time, even if the subject eventually abandons the expectation of poor information and wrong thinking.

On the basis of learning, the formation of expectations is endogenous, and the subject will change the formation of expectations according to the understanding of basic economy. For example, the subject may dynamically transform and use different prediction tools based on the latest prediction error; Or do not change forecasting tools, but look at predictive utility, and use weighted averages to dynamically adjust their weight based on the relative performance of the forecasting tools. Generally speaking, there are two ways to model heterogeneous anticipation. Second, the benefit of learning.

In the future, they have process rationality, their behavior is an adaptive process of continuous learning, and their expectation is also dynamic, and they are constantly adjusting and changing.

Anticipation formation is a learning process. How do economic actors learn and renew their beliefs? North believes that learning is an accumulation process that depends on a number of elements.

In this process of accumulation of learning, will the economy converge to REE? Or, by learning, does heterogeneous expectation converge to rational expectation? There is no doubt that convergence depends on whether the initial expected error decreases or magnifies as the economy evolves and the accumulation of learning. On the one hand, due to the limited rationality of the subject, or the incomplete information and knowledge possessed, errors appear in the formation of expectations. Through learning, these errors will disappear within a certain limit, and the expectations gradually change into complete rationality. Under certain conditions, if all economic subjects continuously improve their knowledge, the economy will eventually converge to the state of complete knowledge, that is, REE; , on the other hand, the convergence is a complex process, depending on the established system of all the economic parameters, including the policy parameters, which depends on the structure of the economy as a whole, under the effect of learning this feedback process, the forecast error may be amplified, heterogeneous expected not to convergence, REE in gradual continued, the rational deviation may be bigger than before. Moreover, although the economy will converge to REE through learning under certain conditions, it will not happen until the subject has accumulated enough economic knowledge. During the transition period, the economic results depend on the adaptive learning process.

The main idea of heterogeneous anticipation theory is that economic subjects are not completely rational due to cognitive limitations or information defects. Under the limited rationality, they will change their behaviors with the change of results. In a heterogeneous expected environment, economic outcomes depend on the expectations of all economic actors.

Expected heterogeneity is a key factor in economic fluctuations. Compared with the economy under rational expectations, the range of economic stability will be greatly reduced in an incomplete and heterogeneous knowledge environment. Even if an economy is not impacted by exogenous impact, it may fluctuate due to the expected heterogeneity caused by the subject's knowledge difference and adaptive learning process. First of all, belief, like utility and endowment, is an important source of economy, but also the main communicator of fluctuations. Faith helps determine the key variables associated with the future level of implementation, if economic agents have different beliefs, will the interpretation of the information, under the decentralized "belief", expected inevitably is heterogeneous, resulting in a "optimistic", "pessimistic" subject, the former will economic activity expanded to more than normal, while the latter is opposite; Second, learning is a trial-and-error and progressive process, which is a complex process in which economic subjects revise their mental models based on feedback from the economic environment. In the process, these data generated from the actual economy itself will also be fed back into the update of beliefs, causing the adjustment of economic behavior.

Compared with rational expectation, heterogeneous expectation is a more complicated transmission mechanism, and the impact caused by it, namely economic fluctuation or adjustment, is a response to learning, which is "implicit" economic variability. By forming expectations, learning breaks the tight connection between economic variables and the basic state of the economy, thus bringing about additional fluctuations. Usually, in the decentralized decision-making of economic society, subjects only know their own goals, constraints and beliefs. In order to understand the overall economic status, they use observational data to continuously learn and update beliefs. And belief has this property: it affects the process by which the real data of the economy is produced, and the latter in turn affects its formation. Under the condition of the economic relationship between the autocorrelation, belief for the future of key economic variables influence their current level, and the levels of these variables are in turn reinforce beliefs, which result in the level of variable now contains information to reduce future economic situation, the uncertainty of future economic increase, produce fluctuations in the real economy.

Heterogeneity is also expected to strengthen and amplify the underlying transmission mechanisms of the economy. In the process of learning, the revision of the belief and the change of the expectation of economic subjects will produce the impact of endogenous aggregate demand, which will not only transmit but also amplify the impact of exogenous economic changes. Heterogeneous expectations can directly trigger fluctuations in market confidence, resulting in fluctuations in the form of demand-driven financial markets or the real economy, or slowing the rate at which supply shocks disappear. More seriously, when expected heterogeneity accumulates to a certain extent, the entire economic system explodes away from the steady growth path and falls into ineffective, decentralized multiple equilibria.

Inflation durability is an important aspect of macroeconomic durability. Under rational expectations, the persistence or inertia of the economy is generally attributed to consumption habits, the indexation of lagging inflation in price adjustment, rule of thumb behavior, or various adjustment costs. In heterogeneous anticipation, learning is another important factor in the generation of economic persistence, different from the "automatic" factors of habituation and indexation.

Heterogeneity is expected to increase the durability of the inflation process. Under rational expectations, inflation expectations are equal to the linear combination of macroeconomic variables. In the context of incomplete heterogeneous knowledge, economic subjects do not fully know the exact structure of the economy, the preferences of policy makers, or the size and nature of economic shocks. The uncertainty caused by incomplete information and asymmetric information in the formation of these expectations will force them to keep learning. Learning this gradual process leads to dynamic changes in inflation expectations, resulting in a greater sequential correlation of inflation, thus increasing the persistence of inflation. The size of this dynamic change and the degree of sequence correlation increase with the increase of learning benefits. Learning will not only amplify and prolong the response of inflation to shocks, but may even lead to marked, persistent and endogenous deviations from rational expectations, such as inflation fears and stagflation. A sustained increase in inflation would raise the price of disinflation.

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