Updated on 2024/08/29

写真a

 
HIGASHI Youichiro
 
Organization
Faculty of Humanities and Social Sciences Professor
Position
Professor
External link

Degree

  • Ph.D. in Economics ( 2008.5   University of Rochester )

Research Interests

  • 意思決定理論

  • 主観的不確実性

  • 曖昧さ

Research Areas

  • Humanities & Social Sciences / Economic theory

Research History

  • Okayama University   Faculty of Economics   Professor

    2017.4

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  • Okayama University   Faculty of Economics   Associate Professor

    2009.4 - 2017.3

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  • Hosei University   Faculty of Economics   Assistant Professor

    2008.4 - 2009.3

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Papers

  • Dynamically consistent menu preferences Reviewed

    Youichiro Higashi, Kazuya Hyogo, Gil Riella

    Economic Theory   2024.7

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    Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

    DOI： 10.1007/s00199-024-01593-6

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    Other Link： https://link.springer.com/article/10.1007/s00199-024-01593-6/fulltext.html

  • Costly Subjective Learning

    Youichiro Higashi, Kazuya Hyogo, Norio Takeoka

    KIER Discussion Paper Series   1040   2020.8

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  • Comparative impatience under random discounting Reviewed

    Youichiro Higashi, Kazuya Hyogo, Norio Takeoka, Hiroyuki Tanaka

    ECONOMIC THEORY   63 ( 3 )   621 - 651   2017.3

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    Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER  

    The random discounting model has been used as a tractable model which is consistent with preference for flexibility. By taking Goldman (J. Econ. Theory 9:203-222, 1974) as an example, we illustrate that under random discounting, the average time preference and preference for flexibility may be conflicting to each other and their mixed effect contributes to revealed impatience. To obtain sharp results in comparative statics, we ask under what kind of probability shifts on discount factors, it is possible to say that one agent always exhibits a more impatient choice than the other even when both agents have flexibility concern. We provide a behavioral definition of impatience comparisons and identify that the relative degree of impatience is measured as a probability shift of a random discount factor in the monotone likelihood ratio order.

    DOI： 10.1007/s00199-015-0950-3

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  • Subjective random discounting and intertemporal choice Reviewed

    Youichiro Higashi, Kazuya Hyogo, Norio Takeoka

    Behavioral Economics of Preferences, Choices, and Happiness   523 - 571   2016.1

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    Language：English   Publishing type：Part of collection (book)   Publisher：Springer Japan  

    This chapter provides an axiomatic foundation for a particular type of preference shock model called the random discounting representation where a decision maker believes that her discount factors change randomly over time. For this purpose, we formulate an infinite horizon extension of Dekel, Lipman, and Rustichini (Econometrica 69:891–934, 2001), and identify the behavior that reduces all subjective uncertainties to those about future discount factors. We also show uniqueness of subjective belief about discount factors. Moreover, a behavioral comparison about preference for flexibility characterizes the condition that one’s subjective belief second-order stochastically dominates the other. Finally, the resulting model is applied to a consumption-savings problem.

    DOI： 10.1007/978-4-431-55402-8_20

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  • Stochastic endogenous time preference Reviewed

    Youichiro Higashi, Kazuya Hyogo, Norio Takeoka

    JOURNAL OF MATHEMATICAL ECONOMICS   51   77 - 92   2014.3

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    Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE SA  

    Preference for flexibility arises inherently in sequential decision making. However, a majority of the literature has limitations to capture a changing preference for flexibility across time in the sense that such an attitude is independent of past actions. This study incorporates the histories of past actions into an infinite-horizon extension of Dekel et al. (2001) and models a decision maker whose attitude toward flexibility evolves over time from the uncertainty of future time preference or discount factors. Moreover, we provide behavioral comparisons of the degree of patience across different histories and characterize the shift of subjective beliefs about discount factors in the sense of an increasing convex and concave stochastic order. (C) 2014 Elsevier B.V. All rights reserved.

    DOI： 10.1016/j.jmateco.2014.01.011

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  • Lexicographic expected utility with a subjective state space Reviewed

    Youichiro Higashi, Kazuya Hyogo

    ECONOMIC THEORY   49 ( 1 )   175 - 192   2012.1

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    Language：English   Publishing type：Research paper (scientific journal)   Publisher：SPRINGER  

    This paper provides a model that allows for a criterion of admissibility based on a subjective state space. For this purpose, we build a non-Archimedean model of preference with subjective states, generalizing Blume et al. (Econometrica 59:61-79, 1991), who present a non-Archimedean model with exogenous states; and Dekel et al. (Econometrica 69:891-934, 2001), who present an Archimedean model with an endogenous state space. We interpret the representation as modeling an agent who has several "hypotheses" about her state space, and who views some as "infinitely less relevant" than others.

    DOI： 10.1007/s00199-010-0546-x

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  • Subjective random discounting and intertemporal choice Reviewed

    Youichiro Higashi, Kazuya Hyogo, Norio Takeoka

    JOURNAL OF ECONOMIC THEORY   144 ( 3 )   1015 - 1053   2009.5

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    Language：English   Publishing type：Research paper (scientific journal)   Publisher：ACADEMIC PRESS INC ELSEVIER SCIENCE  

    This paper provides an axiomatic foundation for a particular type of preference shock model called the random discounting representation where a decision maker believes that her discount factors change randomly over time. For this purpose, we formulate an infinite horizon extension of [E. Dekel, B. Lipman, A. Rustichini, Representing preferences with a unique subjective state space, Econometrica 69 (2001) 891-934], and identify the behavior that reduces all subjective uncertainties to those about future discount factors. We also show uniqueness of subjective belief about discount factors. Moreover, a behavioral comparison about preference for flexibility characterizes the condition that one's subjective belief second-order stochastically dominates the other. Finally, the resulting model is applied to a consumption-savings problem. (C) 2008 Elsevier Inc. All rights reserved.

    DOI： 10.1016/j.jet.2008.09.002

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  • History-Dependent Random Discounting Reviewed

    Youichiro Higashi, Kazuya Hyogo, Norio Takeoka

    NUMERICAL ANALYSIS AND APPLIED MATHEMATICS, VOLS 1 AND 2   1168   965 - +   2009

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    Language：English   Publishing type：Research paper (international conference proceedings)   Publisher：AMER INST PHYSICS  

    In the literature of dynamic models under uncertainty, it is commonly assumed that uncertainty is resolved gradually over time and its resolution is independent of the actions taken by a decision maker up to that time period. However, contingencies in the decision maker's mind may change and even increase over time according to habits that have evolved by experiences, actions, or consumptions in the past. We provide an axiomatic model where the decision maker faces uncertainty about her own time preference or discount factors in future and these uncertainty may evolve according to histories or habits from the past consumption.

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  • Comment on "Ellsberg's two-color experiment, portfolio inertia and ambiguity" Reviewed

    Youichiro Higashi, Sujoy Mukerji, Norio Takeoka, Jean-Marc Tallon

    INTERNATIONAL JOURNAL OF ECONOMIC THEORY   4 ( 3 )   433 - 444   2008.9

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    Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-BLACKWELL PUBLISHING, INC  

    In the setting of Ellsberg's two-color experiment, Mukerji and Tallon ( 2003) claim, without relying on particular representations, that ambiguity-averse behavior implies subjective portfolio inertia. In this note, we point out using a counterexample that their axioms are not enough to establish the result. We fill in the gap in their argument using additional axioms and argue that these axioms are of their own interest in that they behaviorally separate two prominent models of ambiguity: the maximin expected utility and smooth ambiguity models.

    DOI： 10.1111/j.1742-7363.2008.00087.x

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  • Firm specific human capital and unemployment in a growing economy Reviewed

    Youichiro Higashi

    JAPAN AND THE WORLD ECONOMY   14 ( 1 )   35 - 44   2002.1

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    Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

    This study analyzes how the intensive use of firm specific human capital in firms affects the unemployment rate. For this purpose, I introduce into an equilibrium search model the possibility that workers quit their jobs. A worker changes his job when a firm that newly enters into the market offers a higher wage than his current wage. If firm specific human capital is important, it is difficult for a worker to quit his job, and, in consequence, the number of workers who quit their jobs is small. Thus, the unemployment rate is low. If the speed of technology obsolescence is high, the unemployment rate is high. (C) 2002 Elsevier Science B.V. All rights reserved.

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Research Projects

  • An axiomatic analysis of models of persuasion

    Grant number：24K04785  2024.04 - 2028.03

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (C)

    東 陽一郎

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    Grant amount：\4680000 （ Direct expense: \3600000 、 Indirect expense：\1080000 ）

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  • 割引コストのもとで情報構造を最適に決定する主体の理論的分析

    Grant number：20K01562  2020.04 - 2024.03

    日本学術振興会  科学研究費助成事業  基盤研究(C)

    東 陽一郎

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    Grant amount：\4420000 （ Direct expense: \3400000 、 Indirect expense：\1020000 ）

    本年度は、主体が情報取集を行うが、それが分析者に直接観察可能ではない一般モデルの公理化を行った。また、分析で得られたモデルの解釈を昨年度から変えて、よりモデルの分析が説得的になるように試みた。昨年度の解釈は、主体の情報収集に関するコストは、情報収集にかかる時間から発生するコストにもよるとしていた。この解釈ではなく、既存研究での情報収集のコストは、主体が直面するメニューから得られると予想される（粗）利得から独立である点に注目をすることにした。この点に注目し、既存研究を含む我々の一般モデルでは、情報収集のコストは、（粗）利得に依存するものと考えるように解釈を変更した。これは、情報収集を行う主体が、情報を専門家から得る場合、専門家への支払いは（粗）利得に依存することがありえることより正当化が可能と思われる。この解釈を変更した研究を、慶応義塾大学経済学研究所のミクロ経済学ワークショップで報告した。
    本年度は、以上で述べた一般モデルの公理化に続いて、一般モデルの公理を適切に弱めることで、一般モデルは許容されていない、情報収集を行うことに加えて曖昧さを回避したいと思う主体のモデル化を考え始めた。情報収集を行う一般モデルの重要な公理は、関数形の準凸性を保証する公理である。この公理は、曖昧さを回避したいと思う主体を排除する。よって、関数形の準凸性を保証する公理を取り除くが、モデルの特徴づけを可能とする公理を追加することを考えている。現在、一定の結果を得ているが、論文として完成するためには、引き続き分析が必要である。

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  • 誘惑に関する学習を伴う意思決定モデルの理論分析

    Grant number：17K03626  2017.04 - 2023.03

    日本学術振興会  科学研究費助成事業  基盤研究(C)

    東 陽一郎

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    Grant amount：\4420000 （ Direct expense: \3400000 、 Indirect expense：\1020000 ）

    本年度は、Dekel, Lipman, and Rustichini (2001)による一般の加法的期待効用表現でベイズ改訂を行う主体を様々な整合性の条件で特徴づけ、それらの結果を様々なモデルに応用した論文を改訂した。本年度は、特に、様々なモデルへの応用の内容を変更・追加した。具体的には、Stovall (2010)によるmultiple temptation representation、Dekel, Lipman Rustichini (2009)によるuncertain strength of temptation representationとno-uncertainty representation、Sarver (2008)によるanticipating regret representationである。
    これらの応用で重要なのは、加法的期待効用表現には正の主観的状態と負の主観的状態が存在することである。情報が正と負の主観的状態のどちら、又は、両方を変化させるかにより、用いることのできる整合性の条件が異なる。本年度は、uncertain strength of temptation representationとno-uncertainty representationの分析を追加した。まず、uncertain strength of temptation representationでは主体は誘惑の強度に関して不確実性をもつ。本論文で用いた関数形（これらの条件はDLR2でも満たされることが確認できる）の下では、uncertain strength of temptation representationにおいて誘惑の強度に関する信念が一意であることを示した。この信念の一意性は、ベイズ改訂の分析を行う際に重要である。次いで、no-uncertainty representationでは、誘惑の不確実性がなく、主体は複数の誘惑選好に同時に影響される。このモデルでは、誘惑選好上の信念は存在しないが、本論文の結果は、動学的に整合的な行動がモデルでどう対応するかを明らかにしている。

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  • Dynamic analysis of decision making with information acquisition

    Grant number：15K03371  2015.04 - 2019.03

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (C)

    Hyogo Kazuya, Takeoka Norio, Higashi Youichiro

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    Grant amount：\3770000 （ Direct expense: \2900000 、 Indirect expense：\870000 ）

    In this study, dynamic model with information acquisition was analyzed by two approaches. One is analysis of subjective information and the other is analysis of objective information. In the former, we adopted the discussion of the additive cost of information acquisition in the prior literature, and succeeded in deriving an information acquisition model with multiplicative cost due to the discount factors widely used in the standard dynamic models. However, an analysis of the structure of the multiplicative costs has not been completed yet. On the latter, only the updating of belief after receiving the information was analyzed. However, we make it possible to analyze a general model that can also handle information about uncertainties about future temptations that has not been analyzed previously.

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  • A Theory of Subjective Information Structures

    Grant number：15K03351  2015.04 - 2018.03

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (C)

    Takeoka Norio, HIGASHI Youichiro, HYOGO Kazuya, Noor Jawwad, Piermont Evan, Teper Roee, UI Takashi

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    Grant amount：\4420000 （ Direct expense: \3400000 、 Indirect expense：\1020000 ）

    In a dynamic model under uncertainty, a standard model is the Bayesian model, where a decision maker has a information structure consisting of an initial prior over a state space and signals, and he updates the initial prior according to signals. However, this information structure is a private information of the decision maker and is not directly observable to the outside observer or analyst.
    This research extends Savage's model about subjective probabilities and derives not only subjective probabilities but also an information structure from preference. We extend the existing literature toward a multi-period setting and axiomatize a model with endogenous selection of information structure. Moreover, we extend the model to incorporate learning about future tastes as well as learning about information about states.

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  • An analysis of the effect of ambiguity about innovation on economic growth and productivity

    Grant number：25380230  2013.04 - 2017.03

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (C)

    Higashi Youichiro

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    Grant amount：\4420000 （ Direct expense: \3400000 、 Indirect expense：\1020000 ）

    I construct an endogenous growth model, where the probability of succeeding in innovation is ambiguous and assumed to be contained in an interval. In this model, a firm that succeeds in innovation conducts investment in improving its productivity. Before succeeding in innovation, a firm evaluates the lifetime profit by the lowest possible probability. After succeeding in innovation, however, a firm evaluates the lifetime profit by the highest probability. This property implies that if the innovation probability becomes more ambiguous, less innovation is conducted and the productivity becomes lower. An endogenous growth model with a single innovation probability has a difficulty in explaining this feature.

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  • A unified analysis of the unemploymentrate and employment system by search theory

    Grant number：23730191  2011 - 2012

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Young Scientists (B)

    HIGASHI Youichiro

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    Grant amount：\2730000 （ Direct expense: \2100000 、 Indirect expense：\630000 ）

    In this study, I construct a search model in which the unemployment rate and employment system are simultaneously determined. I show that the model has multiple equilibria because firms’ employment contract choices have strategic complementarity. In an equilibrium corresponding to Japanese economy, firms use long-term employment contracts, firm specific human capital is intensively accumulated, and the unemployment rate is low. In another equilibrium corresponding to U.S. economy, firms use short-term contracts, firm specific human capital is not intensively accumulated, and the unemployment rate is high.

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  • Analysis of information demand and the value of information with ambiguous information quality

    Grant number：21730161  2009 - 2010

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Young Scientists (B)

    HIGASHI Youichirou

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    Grant amount：\2730000 （ Direct expense: \2100000 、 Indirect expense：\630000 ）

    When an agent doesn't observe the parameter of a decision problem, she observes a signal correlated with the parameter and chooses the optimal action. The agent does not necessarily have the whole knowledge of how the signal is related with the parameter. This means that the information quality of the signal is ambiguous. In this research, I analyze how precise signal the agent obtains, called information demand, and the value of information when the information quality of the signal is ambiguous.

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