Updated on 2024/11/08

写真a

 
KAMIJO, Yoshio
 
Affiliation
Faculty of Political Science and Economics, School of Political Science and Economics
Job title
Professor
Degree
経済学博士 ( 早稲田大学(日本) )

Research Experience

  •  
     
     

    Waseda University Institue for Advanced Study   Assistant Professor

Education Background

  •  
     
     

    Waseda University  

  •  
     
     

    Waseda University   Graduate School, Division of Economics  

Research Areas

  • Economic theory

Research Interests

  • 行動経済学

  • 実験経済学

  • ゲーム理論

  • 理論経済学

Awards

  • 研究科長賞(早稲田大学)

    2009  

  • 飯島賞(早稲田大学)

    2004  

 

Papers

  • Changes in social norms during the early stages of the COVID-19 pandemic across 43 countries

    Giulia Andrighetto, Aron Szekely, Andrea Guido, Michele Gelfand, Jered Abernathy, Gizem Arikan, Zeynep Aycan, Shweta Bankar, Davide Barrera, Dana Basnight-Brown, Anabel Belaus, Elizaveta Berezina, Sheyla Blumen, Paweł Boski, Huyen Thi Thu Bui, Juan Camilo Cárdenas, Đorđe Čekrlija, Mícheál de Barra, Piyanjali de Zoysa, Angela Dorrough, Jan B. Engelmann, Hyun Euh, Susann Fiedler, Olivia Foster-Gimbel, Gonçalo Freitas, Marta Fülöp, Ragna B. Gardarsdottir, Colin Mathew Hugues D. Gill, Andreas Glöckner, Sylvie Graf, Ani Grigoryan, Katarzyna Growiec, Hirofumi Hashimoto, Tim Hopthrow, Martina Hřebíčková, Hirotaka Imada, Yoshio Kamijo, Hansika Kapoor, Yoshihisa Kashima, Narine Khachatryan, Natalia Kharchenko, Diana León, Lisa M. Leslie, Yang Li, Kadi Liik, Marco Tullio Liuzza, Angela T. Maitner, Pavan Mamidi, Michele McArdle, Imed Medhioub, Maria Luisa Mendes Teixeira, Sari Mentser, Francisco Morales, Jayanth Narayanan, Kohei Nitta, Ravit Nussinson, Nneoma G. Onyedire, Ike E. Onyishi, Evgeny Osin, Seniha Özden, Penny Panagiotopoulou, Oleksandr Pereverziev, Lorena R. Perez-Floriano, Anna-Maija Pirttilä-Backman, Marianna Pogosyan, Jana Raver, Cecilia Reyna, Ricardo Borges Rodrigues, Sara Romanò, Pedro P. Romero, Inari Sakki, Angel Sánchez, Sara Sherbaji, Brent Simpson, Lorenzo Spadoni, Eftychia Stamkou, Giovanni A. Travaglino, Paul A. M. Van Lange, Fiona Fira Winata, Rizqy Amelia Zein, Qing-peng Zhang, Kimmo Eriksson

    Nature Communications   15 ( 1 )  2024.02

     View Summary

    Abstract

    The emergence of COVID-19 dramatically changed social behavior across societies and contexts. Here we study whether social norms also changed. Specifically, we study this question for cultural tightness (the degree to which societies generally have strong norms), specific social norms (e.g. stealing, hand washing), and norms about enforcement, using survey data from 30,431 respondents in 43 countries recorded before and in the early stages following the emergence of COVID-19. Using variation in disease intensity, we shed light on the mechanisms predicting changes in social norm measures. We find evidence that, after the emergence of the COVID-19 pandemic, hand washing norms increased while tightness and punishing frequency slightly decreased but observe no evidence for a robust change in most other norms. Thus, at least in the short term, our findings suggest that cultures are largely stable to pandemic threats except in those norms, hand washing in this case, that are perceived to be directly relevant to dealing with the collective threat.

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  • Votes for excluded minorities and the voting behavior of the existing majority: A laboratory experiment

    Yoichi Hizen, Yoshio Kamijo, Teruyuki Tamura

    Journal of Economic Behavior & Organization   209   348 - 361  2023.05

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  • Risk-Averse and Self-Interested Shifts in Groups in Both Median and Random Rules

    Yoshio Kamijo, Teruyuki Tamura

    Games   14 ( 1 ) 16 - 16  2023.02

     View Summary

    The purpose of this study was to determine whether attitudes toward risk and altruism are affected by being in a group or being alone. In contrast to previous economic research on group decision-making, we excluded the effects of group informal discussions, which are thought to be a “black box” when individuals make decisions in a group. In this regard, the subjects in our experiment were only requested to show their faces to the other members, without further communication. Moreover, we adopted two collective decision rules, i.e., the median rule and the random rule, which provide the truth-telling mechanism. In the experiments of both anonymous investment and donation, we found that the subjects who made decisions in a group offered significantly lower amounts than those who made decisions alone, after controlling for individuals’ risk and altruistic preferences. The findings imply that people are more risk-averse and self-interested when they are in a group, regardless of which collective decision rules are adopted.

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  • Designing division of labor with strategic uncertainty within organizations: Model analysis and a behavioral experiment

    Yoshio Kamijo, Daisuke Nakama

    Journal of Economics and Management Strategy    2022

     View Summary

    For managers who are responsible for designing the division of labor, there are prototypes such as the divisional and functional designs, but insufficient knowledge of what to consider when selecting them. To address this shortfall, we developed a multiple economic game model with a two-step structure to examine the strategic interdependence between the two prototypes. We analyzed the model from three different perspectives: a traditional analysis, an equilibrium analysis, and a behavioral analysis followed by a laboratory experiment. While the first analysis revealed that the functional design would outperform divisional design when individual decisions are exogenous, the game theoretic equilibrium analysis demonstrated that the two prototype designs have similar equilibria when individuals are rational. However, assuming that individuals made autonomous decisions with accessible information under given organizational structures, behavioral analysis derived predictions that the divisional design was more likely to produce favorable consequences than the functional design. This prediction was confirmed by the economic experiment in the laboratory. These results imply that the strategic uncertainty within organizations differs according to the designs and affects organizational consequences.

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  • Bargaining over a jointly produced pie: The effect of the production function on bargaining outcomes.

    Ai Takeuchi, Róbert F. Veszteg, Yoshio Kamijo, Yukihiko Funaki

    Games Econ. Behav.   134   169 - 198  2022

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  • Investor's Pessimistic and False Belief About Trustworthiness and Stake Size in Trust Decision1

    Kiri Kuroda, Yoshio Kamijo, Tatsuya Kameda

    Japanese Psychological Research   63 ( 2 ) 85 - 94  2021.04

     View Summary

    Trust is a vital element of any society. Previous studies using trust games have provided insight into understandings of trusting behavior. However, investors' behaviors can be confounded by their risk preferences in the game, and little is known about the relationship between stake size and beliefs of others' good intentions underlying trust. We thus used a variant of the trust game and conducted two experiments to examine how stake size affects investors' beliefs about receivers' trustworthiness, with model-based analyses. We showed that, when holding all else equal, investors trusted more, but their expectations of reciprocation declined as stake size increased. However, actual receivers' reciprocation rates showed the opposite trend to investors' pessimistic beliefs. Furthermore, following previous studies in social psychology, we hypothesized that investors' social preferences (social value orientation) moderated the beliefs underlying trust, but they had no explanatory powers in investors' expectations of reciprocation. These results suggest that peoples' naive beliefs about stake size play a more important role in trust decisions than expected.

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  • The role of peer reward and punishment for public goods problems in a localized society

    Hiroki Ozono, Yoshio Kamijo, Kazumi Shimizu

    Scientific Reports   10 ( 1 )  2020.12  [Refereed]

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    15
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  • Effect of proxy voting for children under the voting age on parental altruism towards future generations

    Yoshio Kamijo, Teruyuki Tamura, Yoichi Hizen

    Futures   122  2020.09  [Refereed]

     View Summary

    © 2020 The Author(s) What types of people are most concerned about the sustainability of our society? Does empowering such people in the political process influence us to make collective decisions that best serve the interests of future generations? This study invites 1000 parents with children under the legal voting age and 1000 parents with children over the legal voting age to an incentivized donation experiment in which a donation will be made to non-profit organizations committed to a better future society. The size of the donation per participant is determined by vote among the participants. We compare two voting rules: ordinary voting, whereby each participant is given one ballot, and proxy voting, whereby parents with unenfranchised children are given an extra ballot on behalf of their children. We observe that, with ordinary voting, the mothers with children under the voting age exhibit a higher degree of altruism towards future generations. With proxy voting, however, this distinction disappears. Furthermore, with proxy voting, the overall average donation indicated by participants is smaller than that indicated under ordinary voting. These observations imply that empowering institutionally those who tend to be more altruistic does not necessarily result in collective decisions that are more altruistic towards future generations.

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  • Even Bad Social Norms Promote Positive Interactions

    Yoshio Kamijo, Yosuke Kira, Kohei Nitta

    SCIENTIFIC REPORTS   10 ( 1 )  2020.05

     View Summary

    Social norms for cooperation are often supported by positive and negative sanctions. Simultaneously, positive interactions in human relationships via sanctions are promoted by positive social behavior. This study investigates the relationship between social behavior and sanctions based on economic laboratory experiments. Participants with unique IDs make decisions on the contribution to public goods, which is inefficient for society. After participating in the public goods game, they decide whether to use the sanctions. The type of sanctions are varied, such as no sanction, only punishable, only rewardable, and all of these are possible. We found that inefficient social behavior increases under conditions where participants can reward each other and that the level of social activity and rewards are positively correlated. To exclude the possibility of the participants misunderstanding inefficiency, we performed an additional experiment that emphasizes the meaning of inefficiency that the contribution toward public goods reduces profits in society as a whole. We found that even with this emphasis, the high level of contributions is sustained when sanctions are possible. A group-level comparison showed that the group that maintained bad norms used the reward option more. Our results suggest that people maintain bad norms in anticipation of positive interaction.

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  • Time Preferences between Individuals and Groups in the Transition from Hunter-Gatherer to Industrial Societies

    Hernuryadin Yayan, Kotani Koji, Kamijo Yoshio

    SUSTAINABILITY   11 ( 2 )  2019.01  [Refereed]

     View Summary

    Three societies, namely the hunter-gatherer, the agrarian and the industrial, represent the course of human history of cultural and economic development. In this course, each society exhibits distinct cultures and daily life practices that shape human behaviors and preferences, characterizing temporal actions and consequences at the individual and group levels. We examine individual and group time preferences and their relation across the three societies. To this end, we conduct a field experiment to elicit individual and group discount factors in three societies of Indonesia-(i) the fisheries, (ii) the farming and (iii) the urban societies-as proxies of the hunter-gatherer, agrarian and industrial societies, respectively. We find that both individual and group discount factors are the lowest (highest) in the fisheries (agrarian) society, while those in the urban society are in the middle. We also observe that the determinants of group discount factors differ across societies: members of the lowest and middle discount factors in a group play an important role in determining the group discount factor in the fisheries society, while only the members with the middle discount factor are key in agrarian and urban societies. Overall, our results suggest that individual and group discount factors non-monotonically change as societies transition from fisheries to agrarian and from agrarian to urban and that comparatively shortsighted people (the lowest and middle) are more influential than farsighted people in determining group time preferences.

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  • Generativity and social value orientation between rural and urban societies in a developing country

    Timilsina Raja R, Kotani Koji, Kamijo Yoshio

    FUTURES   105   124 - 132  2019.01  [Refereed]

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  • Voting on behalf of a future generation: A laboratory experiment

    Kamijo Y, Hizen Y, Saijo T, Tamura T

    Sustainability (Switzerland)   11 ( 16 ) 4271 - 4271  2019  [Refereed]

     View Summary

    This paper investigates a new voting rule wherein some people are given extra votes to serve as proxies for future generations. We predict that this voting scheme affects the voting behavior of those who do not receive an extra vote (i.e., single-ballot voters) because they are less likely to become a pivot, while proxy voters are expected to behave in support of the future generation. To test this prediction, we compare three scenarios wherein single-ballot voters would cast a vote: (a) one-voter-one-vote scenario wherein all voters cast only a single ballot; (b) a standard proxy-voting scenario wherein other voters cast two ballots, and the second vote is to cast for the benefit of a future generation; and (c) a non-proxy-voting scenario wherein other voters cast two ballots with no explanation for the second vote. The result shows that single-ballot voters are less inclined to vote for the future-oriented option in (c) than in (a). This indicates the potential drawback of the new voting scheme. However, there is no difference in the single-ballot voters’ decision between (a) and (b), indicating that the explanation of the second ballot as the proxy is important for reducing the intergenerational inequality through this voting reform.

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  • Punishing second-order free riders before first-order free riders: The effect of pool punishment priority on cooperation

    Hiroki Ozono, Yoshio Kamijo, Kazumi Shimizu

    SCIENTIFIC REPORTS   7 ( 1 ) 14379  2017.10  [Refereed]

     View Summary

    Second-order free riders, who do not owe punishment cost to first-order free riders in public goods games, lead to low cooperation. Previous studies suggest that for stable cooperation, it is critical to have a pool punishment system with second-order punishment, which gathers resources from group members and punishes second-order free riders as well as first-order free riders. In this study, we focus on the priority of punishment. We hypothesize that the pool punishment system that prioritizes second-order punishment is more likely to achieve cooperation than the system that prioritizes first-order punishment, because the former is more likely to obtain sufficient punishment resources. In the experiments, we compare four pool punishment systems: 1To2 (first-order punishment to second-order punishment), 2To1 (second-order punishment to first-order punishment), 1ONLY (first-order punishment only), and 2ONLY (second-order punishment only). We find that the 2To1 and 2ONLY systems can receive more support than the 1To2 and 1ONLY systems and only the 2To1 system can achieve high cooperation. However, the effect of priority of second-order punishment is observed only when the punishment ratio (PR) is low (Experiment 1), not high (Experiment 2), in which the punishment resource is relatively abundant.

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  • Coincidence of the Shapley value with other solutions satisfying covariance

    Koji Yokote, Yukihiko Funaki, Yoshio Kamijo

    MATHEMATICAL SOCIAL SCIENCES   89   1 - 9  2017.09  [Refereed]

     View Summary

    We identify the necessary and sufficient condition under which the Shapley value coincides with the prenucleolus for general TU games. For 0-normalized 3-person games, the coincidence holds if and only if the game is symmetric or satisfies the PS property (Kar et al., 2009). We also identify the necessary and sufficient coincidence condition in the following allocation problems: the airport games (Littlechild and Owen, 1973), the bidder collusion games (Graham et al., 1990) and the polluted river games (Ni and Wang, 2007). The coincidence between the Shapley value and the CIS and ENSC values is discussed as well. (C) 2017 Elsevier B.V. All rights reserved.

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  • Negotiating with the future: incorporating imaginary future generations into negotiations

    Yoshio Kamijo, Asuka Komiya, Nobuhiro Mifune, Tatsuyoshi Saijo

    Sustainability Science   13 ( 4 ) 1193  2017.05  [Refereed]

     View Summary

    The article, Negotiating with the future: incorporating imaginary future generations into negotiations, written by Yoshio Kamijo, Asuka Komiya, Nobuhiro Mifune and Tatsuyoshi Saijo, was originally published Online First without open access. After publication in volume 12, issue 3, page 409–420 the author decided to opt for Open Choice and to make the article an open access publication. Therefore, the copyright of the article has been changed to © The Author(s) 2017 and the article is forthwith distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons. org/licenses/by/4.0/), which permits use, duplication, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

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  • Negotiating with the future: incorporating imaginary future generations into negotiations

    Yoshio Kamijo, Asuka Komiya, Nobuhiro Mifune, Tatsuyoshi Saijo

    SUSTAINABILITY SCIENCE   12 ( 3 ) 409 - 420  2017.05  [Refereed]

     View Summary

    People to be born in the future have no direct influence on current affairs. Given the disconnect between people who are currently living and those who will inherit the planet left for them, individuals who are currently alive tend to be more oriented toward the present, posing a fundamental problem related to sustainability. In this study, we propose a new framework for reconciling the disconnect between the present and the future whereby some individuals in the current generation serve as an imaginary future generation that negotiates with individuals in the real-world present. Through a laboratory-controlled intergenerational sustainability dilemma game (ISDG), we show how the presence of negotiators for a future generation increases the benefits of future generations. More specifically, we found that when faced with members of an imaginary future generation, 60% of participants selected an option that promoted sustainability. In contrast, when the imaginary future generation was not salient, only 28% of participants chose the sustainable option.

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  • Sustainability of common pool resources

    Raja Rajendra Timilsina, Koji Kotani, Yoshio Kamijo

    PLOS ONE   12 ( 2 ) e0170981  2017.02  [Refereed]

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    Sustainability has become a key issue in managing natural resources together with growing concerns for capitalism, environmental and resource problems. We hypothesize that the ongoing modernization of competitive societies, which we refer to as "capitalism," affects human nature for utilizing common pool resources, thus compromising sustainability. To test this hypothesis, we design and implement a set of dynamic common pool resource games and experiments in the following two types of Nepalese areas: ( i) rural ( non-capitalistic) and ( ii) urban ( capitalistic) areas. We find that a proportion of prosocial individuals in urban areas is lower than that in rural areas, and urban residents deplete resources more quickly than rural residents. The composition of proself and prosocial individuals in a group and the degree of capitalism are crucial in that an increase in prosocial members in a group and the rural dummy positively affect resource sustainability by 65% and 63%, respectively. Overall, this paper shows that when societies move toward more capitalistic environments, the sustainability of common pool resources tends to decrease with the changes in individual preferences, social norms, customs and views to others through human interactions. This result implies that individuals may be losing their coordination abilities for social dilemmas of resource sustainability in capitalistic societies.

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  • Institutionalize Reciprocity to Overcome the Public Goods Provision Problem.

    Ozono H, Kamijo Y, Shimizu K

    PloS one   11 ( 6 ) e0154321  2016.06  [Refereed]

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  • Preemptive Striking in Individual and Group Conflict

    Nobuhiro Mifune, Yoichi Hizen, Yoshio Kamijo, Yoshitaka Okano

    PLOS ONE   11 ( 5 ) e0154859  2016.05  [Refereed]

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    In this study, we conducted a laboratory experiment to assess preemptive striking by and towards individuals or groups. In the framework of a preemptive strike game, we set the following four conditions: one person faced another person, one person faced a three-person group, a three-person group faced an individual, and a three-person group faced another three-person group. Previous studies have revealed that greed is activated when participants belong to a group, while fear is activated when participants interact with a group, and further, that attacking behaviors in the preemptive strike game are driven by fear. These observations led to a hypothesis that high attack rates would be realized when participants interact with a group, regardless of whether the participants make decisions as individuals or a group. The results of our experiment, however, rejected this hypothesis. Among the four conditions, the attack rate was highest when a three-person group faced an individual. As possible reasons for our observation, we discuss the potential threat stemming from the imbalance in the effectiveness of attack between individuals and groups, and the (incorrect) belief by groups that single individuals would be more likely to attack out of fear.

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  • Overcoming coordination failure using a mechanism based on gradualism and endogeneity

    Yoshio Kamijo, Hiroki Ozono, Kazumi Shimizu

    EXPERIMENTAL ECONOMICS   19 ( 1 ) 202 - 217  2016.03  [Refereed]

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    We examine three tools that can enhance coordination success in a repeated multiple-choice coordination game. Gradualism means that the game starts as an easy coordination problem and moves gradually to a more difficult one. The Endogenous Ascending mechanism implies that a gradual increase in the upper bound of coordination occurs only if coordination with the Pareto superior equilibrium in a stage game is attained. The Endogenous Descending mechanism requires that when the game's participants fail to coordinate, the level of the next coordination game be adjusted such that the game becomes simpler. We show that gradualism may not always work, but in such instances, its effect can be reinforced by endogeneity. Our laboratory experiment provides evidence that a mechanism that combines three tools, herein termed the "Gradualism with Endogenous Ascending and Descending (GEAD)'' mechanism, works well. We discuss how the GEAD mechanism can be applied to real-life situations that suffer from coordination failure.

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  • A new basis and the Shapley value

    Koji Yokote, Yukihiko Funaki, Yoshio Kamijo

    MATHEMATICAL SOCIAL SCIENCES   80   21 - 24  2016.03  [Refereed]

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    The purpose of this paper is to introduce a new basis of the set of all TU games. Shapley (1953) introduced the unanimity game in which cooperation of all players in a given coalition yields payoff. We introduce the commander game in which only one player in a given coalition yields payoff. The set of the commander games forms a basis and has two properties. First, when we express a game by a linear combination of the basis, the coefficients related to singletons coincide with the Shapley value. Second, the basis induces the null space of the Shapley value. (C) 2016 Elsevier B.V. All rights reserved.

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  • Rewards versus punishments in additive, weakest-link, and best-shot contests

    Yoshio Kamijo

    JOURNAL OF ECONOMIC BEHAVIOR & ORGANIZATION   122   17 - 30  2016.02  [Refereed]

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    In this study, we provide a theory to explain how bottom punishment or top reward enhances performance of teams when there is heterogeneity across players in cost-performance relationships. In contrast to the existing literature, we consider three types of performance functions: additive, weakest link (the performance is the min of performances of n contestants), and best shot (the performance is the max of performances of n contestants). For any of the three types, we derive easy-to-check sufficient conditions to judge whether reward or punishment is better. From the sufficient condition for the additive performance function, we know that punishment is better for less heterogeneous people and reward is better for more heterogeneous people. In addition, the sufficient conditions for the best-shot and weakest-link cases suggest that some unintuitive results hold; even under the best-shot (weakest link) performance function, the bottom punishment (top reward) becomes better when the gap in the abilities of contestants becomes very small (large). (C) 2015 Elsevier B.V. All rights reserved.

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  • Who is audited? Experimental study on rule-based tax auditing schemes

    Yoshio Kamijo, Takehito Masuda, Hiroshi Uemura

    Kochi University of Technology-SDE working paper series no. 2015-21   21   1  2015.07

  • Properties based on relative contributions for cooperative games with transferable utilities

    Yoshio Kamijo, Takumi Kongo

    THEORY AND DECISION   78 ( 1 ) 77 - 87  2015.01  [Refereed]

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    By focusing on players' relative contributions, we study some properties for values in positive cooperative games with transferable utilities. The well-known properties of symmetry (also known as "equal treatment of equals") and marginality are based on players' marginal contributions to coalitions. Both Myerson's balanced contributions property and its generalization of the balanced cycle contributions property (Kamijo and Kongo Int J of Game Theory 39:563-571, 2010; BCC) are based on players' marginal contributions to other players. We define relative versions of marginality and BCC by replacing marginal contributions with relative contributions, and examine efficient values satisfying each of the two properties. On the class of positive games, a relative variation of marginality is incompatible with efficiency, and together with efficiency and the invariance property with respect to the payoffs of players under a player deletion, a relative variation of BCC characterizes the proportional value and egalitarian value in a unified manner.

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  • The endogenous objective function of a partially privatized firm: A Nash bargaining approach

    Yoshio Kamijo, Yoshihiro Tomaru

    ECONOMIC MODELLING   39   101 - 109  2014.04  [Refereed]

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    We establish a model wherein a private firm competes with a partially privatized firm whose objective function is endogenously determined through bargaining between owners the welfare-maximizing government and dividend-maximizing private shareholders. Many existing works on partial privatization have assumed that privatization increases the weight of profits in the partially privatized firm's objective, whereas it decreases the weight of welfare. However, our bargaining approach shows that this result can be reversed. (C) 2014 Elsevier B.V. All rights reserved.

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  • Sustaining cooperation in social dilemmas: Comparison of centralized punishment institutions

    Y. Kamijo, T. Nihonsugi, A. Takeuchi, Y. Funaki

    GAMES AND ECONOMIC BEHAVIOR   84   180 - 195  2014.03  [Refereed]

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    This study investigates two centralized punishment institutions for a linear public goods game. These institutions require a certain contribution level and sanction under-contributing players. The two differ in who, among those who do not meet this requirement, receive sanctions. In one institution, all violators are sanctioned, and in the other, only the worst violator(s) is sanctioned. Theoretically, the public goods game of the latter institution yields contributions equal to or greater than that of the former institution with the same requirement and sanction level. The results of an experiment support this theoretical prediction. However, there is a discrepancy between the theory and laboratory observations in that the institution with the theoretically optimal requirement did not yield the highest profit. (C) 2014 Elsevier Inc. All rights reserved.

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  • The collective value: a new solution for games with coalition structures

    Yoshio Kamijo

    TOP   21 ( 3 ) 572 - 589  2013.10  [Refereed]

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    In this study, we provide a new solution for cooperative games with coalition structures. The collective value of a player is defined as the sum of the equal division of the pure surplus obtained by his coalition from the coalitional bargaining and of his Shapley value for the internal coalition. The weighted Shapley value applied to a game played by coalitions with coalition-size weights is assigned to each coalition, reflecting the size asymmetries among coalitions. We show that the collective value matches exogenous interpretations of coalition structures and provide an axiomatic foundation of this value. A noncooperative mechanism that implements the collective value is also presented.

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  • Theoretical and experimental investigations of the performance of keyword auction mechanisms

    Emiko Fukuda, Yoshio Kamijo, Ai Takeuchi, Michiharu Masui, Yukihiko Funaki

    RAND JOURNAL OF ECONOMICS   44 ( 3 ) 438 - 461  2013.09  [Refereed]

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    Two keyword auction mechanisms, the Generalized Second-Price auction (GSP) and the Vickrey-Clarke-Groves mechanism (VCG), were compared theoretically and experimentally. The former is widely used in practice; the latter is not, but it has a dominant strategy equilibrium where all participants bid their true values. In the theoretical investigation, by applying the locally envy-free Nash equilibrium to the VCG, we found that the allocations are efficient and that upper and lower bounds of the auctioneer's revenue coincide in the two mechanisms. A laboratory experiment, in which the revenues and efficiencies were similar in both mechanisms, supported this result.

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  • Smokers, smoking deprivation, and time discounting

    Shoko Yamane, Hiroyasu Yoneda, Taiki Takahashi, Yoshio Kamijo, Yasuhiro Komori, Fumihiko Hiruma, Yoshiro Tsutsui

    Journal of Socio-Economics   45   47 - 56  2013.08  [Refereed]

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    This paper investigates whether smokers exhibit greater time discounting than non-smokers, and how short-term nicotine deprivation affects time discounting. A unique feature of our experiment is that our subjects receive rewards not only of money, but also of actual tobacco. This is done in order to elicit smokers' true preferences. Smokers are more impatient than non-smokers, consistent with previous studies. Additionally, nicotine deprivation makes smokers even more impatient. These results suggest that nicotine concentration has different effects on time preferences in the short and long runs. © 2013 Elsevier Inc.

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  • Bidding behaviors for a keyword auction in a sealed-bid environment.

    Yoshio Kamijo

    Decision Support Systems   56   371 - 378  2013

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  • Whose deletion does not affect your payoff? The difference between the Shapley value, the egalitarian value, the solidarity value, and the Banzhaf value

    Yoshio Kamijo, Takumi Kongo

    EUROPEAN JOURNAL OF OPERATIONAL RESEARCH   216 ( 3 ) 638 - 646  2012.02  [Refereed]

     View Summary

    This study provides a unified axiomatic characterization method of one-point solutions for cooperative games with transferable utilities. Any one-point solution that satisfies efficiency, the balanced cycle contributions property (BCC), and the axioms related to invariance under a player deletion is characterized as a corollary of our general result. BCC is a weaker requirement than the well-known balanced contributions property. Any one-point solution that is both symmetric and linear satisfies BCC. The invariance axioms necessitate that the deletion of a specific player from games does not affect the other players' payoffs, and this deletion is different with respect to solutions. As corollaries of the above characterization result, we are able to characterize the well-known one-point solutions, the Shapley, egalitarian, and solidarity values, in a unified manner. We also studied characterizations of an inefficient one-point solution, the Banzhaf value that is a well-known alternative to the Shapley value. (C) 2011 Elsevier B,V. All rights reserved.

    DOI

    Scopus

    45
    Citation
    (Scopus)
  • Implementation of weighted values in hierarchical and horizontal cooperation structures

    Yoshio Kamijo

    MATHEMATICAL SOCIAL SCIENCES   56 ( 3 ) 336 - 349  2008.11  [Refereed]

     View Summary

    This paper Studies a non-cooperative mechanism implementing a cooperative solution for a situation in which members of a society are Subdivided into groups and/or coalitions and there is asymmetry among the individuals of the society. To describe hierarchical and horizontal cooperation structure simultaneously, we present unified classes of games, the games with social structure. and define a weighted value for these games. We show that our mechanism works in any zero-monotonic environment and implements the Shapley Value, the weighted Shapley value, the Owen's coalitional Value, and the weighted coalitional value, in some special cases. (C) 2008 Elsevier B.V. All rights reserved.

    DOI

    Scopus

    5
    Citation
    (Scopus)

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Research Projects

  • Information disclosure and incomplete belief updating: theory building and testing through economic experiments

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research

    Project Year :

    2022.04
    -
    2027.03
     

  • A new analysis for coalition formation and payoff distributions by a hybrid model of cooperative and non-cooperative games

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research

    Project Year :

    2022.04
    -
    2027.03
     

  • 攻撃力の非対称性と移行による外集団攻撃の心理メカニズムの解明

    日本学術振興会  科学研究費助成事業

    Project Year :

    2021.04
    -
    2026.03
     

    三船 恒裕, 上條 良夫, 多湖 淳

  • Creation of innovation through payment by results (PbR) in agri-environmental policies

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research

    Project Year :

    2020.04
    -
    2024.03
     

  • Experimental Approach for Income Disparity

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research

    Project Year :

    2019.04
    -
    2023.03
     

  • 超高齢化社会の歪みを正す投票制度に関する理論及び実験研究

    日本学術振興会  科学研究費助成事業

    Project Year :

    2018.04
    -
    2023.03
     

    上條 良夫

     View Summary

    高齢化の進行する民主主義国家は等しく有権者の高齢化という問題に直面しており、将来世代の利益は軽視されがちとなる。将来世代の利益を担保できる新た な投票制度として、選挙権年齢未満の子どもを有する親が、子供の代理として投票するという代理投票制度が注目を集めている。本研究では、代理投票制度が本 当に将来の利益に資する選択を導くのか、という問いに対して、理論を構築し、実験室実験およびインターネット調査実験を用いて明らかにしていく。
    予備的調査、平成30年度の調査を通じて、18歳未満の子供を有する人は18歳未満の子供を有しない人と比べて、寄付金額が高い傾向があることが確認で きた。当該結果は繰り返し確認されており、一定の頑健性を有すると考えられる。その一方で、そのような寄付金額が高い人たちであっても、自身の子供の代理 としての意思決定においては、寄付金額が低くなるというパラドキシカルな現象も観察している。
    平成31年度(令和元年度)は、これまでの調査から繰り返し観察されている、代理票においてなぜ親の寄付金額が減少するのかを明らかにするため、さらな るインターネット調査を実施した。調査の目的は、(1)結果の頑健性の確認、(2)代理意思決定において寄付金額が減少する理由の解明、そして、(3)代 理という文脈においても寄付金額を向上させるような仕組みの検討である。そのような仕組みとして、意思決定の理由を子供に見せる、という操作を実施した。
    令和2、3年度は、当該調査の継続調査を実施する予定であったが、新型コロナウイルス感染拡大という異常事態であったことを鑑みて、調査の実施を延期することとした。また、予備的調査をまとめた論文が昨年度国際学術誌に掲載された。

  • 絶大希少事象を考慮した歪み・非対称不確実性・不明確性のリスク経済実験・理論分析

    日本学術振興会  科学研究費助成事業

    Project Year :

    2019.04
    -
    2022.03
     

    小谷 浩示, 西條 辰義, 田中 健太, 柿中 真, 上條 良夫, 青木 隆太

     View Summary

    当該年度の研究計画に沿い、インドネシアと日本で対称と非対称な不確実性と不明確性を伴う絶大希少事象を考慮したリスク行動実験とリスク行動経済理論構築の為の文献調査を行った。フィールド実験、オンラインでの実験、そして、実験室実験を各々行い、現在、その結果は解析中である。行った実験は、不確実性と不明確性下での公共財供給実験、及び、不確実性と不明確性下でのリスク選択実験である。その各々の実験において各被験者は複数の異なる状況(対象な不確実性、対象な不明確性、非対称な不確実性、非対称な不明確性)での行動や選択を決める。よって、上記した一連の実験データを統計分析する事により、人々がどの様な状況でどの様に行動や選択を変化させるのか、可能であり、且つ、こうした研究は、多くの不確実性と不明確性と伴う気候変動問題やその他災害・天災に対応する政策への示唆を提示出来るものとなっている。今の所、当初予定していた通り、不確実な状況と不明確な状況では人々の行動に大きな違いがある様である事、そして、その不確実性と不明確性の分布が対象であるのか、非対称であるのかもデータ分析の結果より少しずつ明らかになってきている。特に、不確実性下と不明確性下の状況でその分布が非対称で歪んでいればいる程、リスク回避型からリスク愛好型へリスク選好が変移する可能性が示唆されており、それらの結果の頑健性を現在、確認している。収集したデータの解析を更に進め論文化するだけでなく、更に実験内容を更新・改良し更なる経済リスク理論の構築とFMRI実験への新たな試みを開始する予定で作業を進めている。

  • New Theory and Experiment of Coalition formation and Payoff Allocation in Cooperative Game

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research

    Project Year :

    2017.04
    -
    2022.03
     

  • Experimental Approach for Rent Seeking Problem

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research

    Project Year :

    2016.04
    -
    2020.03
     

    Kazumi Shimizu

     View Summary

    The most important point about small groups is that they may very well be able to provide themselves with a collective good((Olson ,1965).From the stand of “group size paradox” a la Olson (1965), a large group or a large organization should be failed to win the contest against a small one. However, in the economic realms, many large firms prosper despite the group size paradox suggesting that they should lose the contest.In this study, we will answer this twisted situation between the "group size paradox" and reality.
    We found (1)"Group Size Paradox" doesn’t occur in auction-like contest theoretically, (2)high cooperation was not achieved and that peer reward and punishment did not function when, and only when, the group was divided into localized groups and the payoff structure was locally inefficient.

  • Cooperative in collection action under uncertainty and ambiguity associated with climate change

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research

    Project Year :

    2016.04
    -
    2019.03
     

    Kotani Koji

     View Summary

    We have analyzed (i) how people recognize uncertainty and ambiguity associated with climate change and (i) how the degree of such uncertainty and ambiguity affects people’s cooperative and collective toward adaptation and mitigation of climate change through conducting lab and field experiments. We have found that people who live in urban areas and whose life is far from natural environment have a strong tendency to recognize that climate change is nature-induced along with high uncertainty and ambiguity and to be less cooperative in collective actions toward adaptation and mitigation of climate change. However, we have also found that education and information that reduce the degree of uncertainty and ambiguity associated with climate change within people’s recognition toward climate change can enhance the cooperative behaviors, illustrating the value of information and education for climate change.

  • Experimental Investigations on Group Decision in Strategic Environments

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research

    Project Year :

    2014.04
    -
    2019.03
     

    KAMIJO Yoshio

     View Summary

    This study examined the preference changes of individuals through forming a group using experimental methods. It became clear that by becoming a group, people would like more selfish choices and risk averse choices. We also found that the determinants of group time preference tend to reflect the influence of those who emphasize short-term benefits more than those who emphasize long-term benefits. From experiments using a task (preemptive attack game) wherein participants consider whether or not to make defensive preemptive attacks from fear that an opponent may attack, it became clear that preemptive attacks from a group to an individual was higher than the other conditions.

  • Future Design

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research

    Project Year :

    2016.04
    -
    2018.03
     

    Saijo Tatsuyoshi, HARA Keishiro, HIZEN Yoichi, KAMIJO Yoshio, KOTANI Koji, MIFUNE Nobuhiro, KOMIYA Asuka, TAMURA Teruyuki, SHAHRIER Shibly

     View Summary

    We designed a new game called the Intergenerational Sustainability Dilemma Game (ISDG), and conducted experiments using an imaginary future person (IFP) and not using the person. We found that groups with IFPs chose more sustainable alternative than groups without IFPs did. That is, we observed that introducing IFP in decision making activated “futurability”: An individual exhibits futurability when (s)he experiences an increase in happiness as a result of deciding and acting to forego current benefits as long as it enriches future generations.
    In the Domeny voting that allows children’s voting, some of the people who voted for a policy that helps future generations in a usual voting system changed their minds so that they voted for a policy for current generation.

  • Theoretical and experimental investigations of rewards and punishments

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research

    Project Year :

    2014.04
    -
    2017.03
     

    KAMIJO Yoshio, MIFUNE Nobuhiro, OKANO Yoshitaka

     View Summary

    We provide a game theoretical framework to explain how bottom punishment or top reward enhances performance of teams when there is heterogeneity across players in cost-performance relationships. We derive easy-to-check sufficient conditions to judge whether reward or punishment is better. From the sufficient condition, we know that punishment is better for less heterogeneous people and reward is better for more heterogeneous people if the performance function is additive. To check the theoretical predictions, we conducted the field and laboratory experiments. We found that while the reactions of the actual people to the two incentives are more complex than the predicted behavior by the theory, how they use sticks or carrots are consistent with the theoretical predictions.

  • Experimental and theoretical study of bargaining on actions

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research

    Project Year :

    2013.04
    -
    2016.03
     

    Okano Yoshitaka, KAMIJO YOSHIO, MIFUNE NOBUHIRO

     View Summary

    The essence of the problem we encounter today, such as regional conflict and destruction of environment, is adjustment between persons involved on interests and actions, which is typically done through the negotiation. This research project investigate experimentally how people negotiate in the group, and what they choose. In the preemptive strike game, which is developed in social psychology, groups became more aggressive against individuals. In two-person zero-sum game, groups behave more consistent with Nash equilibrium prediction than do individuals.

  • How can we overcome the coordination/cooperation dilemma under stranger condition?

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research

    Project Year :

    2013.04
    -
    2016.03
     

    Shimizu Kazumi, Kamijo Yoshio, Ozono Haruki

     View Summary

    We examine three tools that can enhance coordination success in a repeated multiple-choice coordination game. Gradualism means that the game starts as an easy coordination problem and moves gradually to a more difficult one. The Endogenous Ascending mechanism implies that a gradual increase in the upper bound of coordination occurs only if coordination with the Pareto superior equilibrium in a stage game is attained. The Endogenous Descending mechanism requires that when the game’s participants fail to coordinate, the level of the next coordination game be adjusted such that the game becomes simpler. Our laboratory experiment proves that a mechanism that combines these three tools, herein termed the “Gradualism-Endogenous Ascending-Endogenous Descending (GEAD)” mechanism, works well.

  • A theoretical analysis of a keyword auction: How rational the current settings of keyword auction are

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research

    Project Year :

    2011
    -
    2013
     

    KAMIJO Yoshio

     View Summary

    The purpose of this research project is to explore how rational the current settings of keyword auctions are by means of a game theoretic analysis and a computer simulation.
    In the first study, we explore a slot supply strategy of a search engine. Based on the revenue prediction from a game theoretic analysis, we show that restricting the number of the ads in a search result page and highlighting the top ads are consistent with the revenue maximization of the sellers.
    In the second study, we explore the bidding behavior of advertisers in a sealed-bid environment, where each bidder does not know the current bids of others. It is shown that even in a sealed bid environment, bid profie of advertisers converges to some equilibrium point in a one-shot game. Simulation results verify that a sealed-bid environment would be beneficial to search engines.

  • A Study on Political Institutions

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research

    Project Year :

    2007
    -
    2012
     

    HIZEN Yoichi, FUNAKI Yukihiko, KOHNO Masaru, TANIGUCHI Naoko, SAKAIYA Shiro, ARAI Kiichiro, KAMIJO Yoshio, IDE Hiroko

     View Summary

    We had a contribution to the development of experimental research in political science in order to establish experimental social sciences, which is the main theme of our scientific research on priority area. We tackled a research question “how can democracies work well?” through laboratory, fMRI and survey experiments. We also published papers and books and held sessions on the effectiveness of experimental methods in political science.

  • Theoretical analysis of position auctions

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research

    Project Year :

    2009
    -
    2010
     

    KAMIJO Yoshio

     View Summary

    A keyword auction where the internet advertisements shown in the search result page are sold is theoretically analyzed. In this study, it is found that the advertising-slot supply strategy which is adopted in practice by the internet search engines is explained by the revenue maximizing principle. In particular, restricting the number of advertisements in a search result page and highlighting the top advertisements enhance the revenue of the search engines.

  • キーワードオークションの理論と実験による研究

  • -

▼display all

Misc

  • Who is audited? Experimental study on rule-based tax auditing

    Y. Kamijo, T Masuda, H. Uemura

      1064  2019.10

  • AN EXPERIMENTAL STUDY OF DOUBLE-TRACK AUCTION

    宇都伸之, 上條良夫, 船木由喜彦

    日本オペレーションズ・リサーチ学会和文論文誌   59   38‐59 - 59  2016.12

     View Summary

    <p>A double-track auction is a new auction mechanism to allocate multiple indivisible goods to buyers, who view items as both substitutes and complements. This auction mechanism is significant since existing auction mechanisms with multiple goods can only allocate substitutes. One experimental study with two goods and two buyers, however, suggests that double-track auctions do not work as the theory predicts due to interference from a theoretically unnoticed price called the "pitfall" price. This study investigates the performance of a double-track auction with an experiment incorporating controls on the pitfall price. In the experiment, two goods are for sale. Two buyers view these goods as complements and bid for them. The experiment consists of two conditions: one with and the other without the pitfall condition. The main result is that the pitfall price negatively affects performance. The pitfall condition achieves competitive equilibrium at a rate that is 60% lower than that without the pitfall condition. However, without the pitfall condition, the auction works as the theory indicates. Therefore, double-track auctions allocate items only when there is no pitfall price.</p>

    DOI CiNii J-GLOBAL

  • The Effect of Managerial Disclosure Decision and Its Regulation on Investment and Lending Behavior : An Analysis of Coordination Games

    上枝 正幸, 上條 良夫

    現代ディスクロージャー研究 = Contemporary disclosure research   ( 14 ) 7 - 23  2014.10

    CiNii

  • Stability and efficiency in perfect foresight situation

    Yoshio Kamijo

    THEORY AND DECISION   75 ( 3 ) 339 - 357  2013.09

     View Summary

    We study the stable standard of behavior in a perfect foresight situation that was introduced by Xue (Econ Theory 11:603-627, 1998). We assume that the inducement relations are invertible and coalition free. We show that the conditions are sufficient for the existence of the nonempty-valued optimistic/conservative stable standard of behavior for perfect foresight situation (OSSB-PF/CSSB-PF). Moreover, we find that an OSSB-PF supports a Pareto-efficient outcome as a stable outcome; if the preference relations are strict, only the Pareto-efficient outcomes are supported by the OSSB-PF.

    DOI

  • The Portfolio Choice of Households and Taxation : An Analysis of a Flow-based Demand Function

    井上 智弘, 上條 良夫

    証券経済研究   0 ( 77 ) 173 - 189  2012.03

    CiNii

  • Whose deletion does not affect your payoff? the difference between the Shapley value, the egalitarian value, the solidarity value, and the Banzhaf value

    Yoshio Kamijo, Takumi Kongo

    European Journal of Operational Research   216 ( 3 ) 638 - 646  2012.02

     View Summary

    This study provides a unified axiomatic characterization method of one-point solutions for cooperative games with transferable utilities. Any one-point solution that satisfies efficiency, the balanced cycle contributions property (BCC), and the axioms related to invariance under a player deletion is characterized as a corollary of our general result. BCC is a weaker requirement than the well-known balanced contributions property. Any one-point solution that is both symmetric and linear satisfies BCC. The invariance axioms necessitate that the deletion of a specific player from games does not affect the other players' payoffs, and this deletion is different with respect to solutions. As corollaries of the above characterization result, we are able to characterize the well-known one-point solutions, the Shapley, egalitarian, and solidarity values, in a unified manner. We also studied characterizations of an inefficient one-point solution, the Banzhaf value that is a well-known alternative to the Shapley value. © 2011 Elsevier B.V. All rights reserved.

    DOI

  • Whose deletion does not affect your payoff? The difference between the Shapley value, the egalitarian value, the solidarity value, and the Banzhaf value

    Yoshio Kamijo, Takumi Kongo

    EUROPEAN JOURNAL OF OPERATIONAL RESEARCH   216 ( 3 ) 638 - 646  2012.02

     View Summary

    This study provides a unified axiomatic characterization method of one-point solutions for cooperative games with transferable utilities. Any one-point solution that satisfies efficiency, the balanced cycle contributions property (BCC), and the axioms related to invariance under a player deletion is characterized as a corollary of our general result. BCC is a weaker requirement than the well-known balanced contributions property. Any one-point solution that is both symmetric and linear satisfies BCC. The invariance axioms necessitate that the deletion of a specific player from games does not affect the other players' payoffs, and this deletion is different with respect to solutions. As corollaries of the above characterization result, we are able to characterize the well-known one-point solutions, the Shapley, egalitarian, and solidarity values, in a unified manner. We also studied characterizations of an inefficient one-point solution, the Banzhaf value that is a well-known alternative to the Shapley value. (C) 2011 Elsevier B,V. All rights reserved.

    DOI

  • 監査制度の生成に関する実験比較制度分析 : 米国型監査システムは経営者を誠実にするのか

    田口 聡志, 上條 良夫

    企業会計   64 ( 1 ) 140 - 147  2012.01

    CiNii

  • 2-H-6 検索連動型広告オークションにおける入札行動についての分析 : 入札額の秘匿環境が収束速度・収入に与える影響について(ゲーム理論(2))

    上條 良夫

    日本オペレーションズ・リサーチ学会秋季研究発表会アブストラクト集   2011   320 - 321  2011.09

    CiNii

  • 2-H-8 Double-Trackオークションの実験研究(ゲーム理論(2))

    宇都 伸之, 上條 良夫, 船木 由喜彦

    日本オペレーションズ・リサーチ学会秋季研究発表会アブストラクト集   2011   324 - 325  2011.09

    CiNii

  • Tax effects on the portfolio choice of households

    井上 智弘, 上條 良夫

    早稲田経済学研究   ( 70 ) 37 - 70  2011.01

    CiNii

  • 監査制度の生成に関する実験比較制度分析:米国型監査システムは経営者を誠実にするのか

    田口・上條

    企業会計     140 - 147  2011

  • 家計の金融資産選択に与える課税の影響

    井上智弘, 上條良夫

    早稲田経済学研究   70  2011

  • The collective value: a new solution for games with coalition structures

    Yoshio Kamijo

    Top    2011

  • 監査制度の生成に関する実験比較制度分析:米国型監査システムは経営者を誠実にするのか

    田口・上條

    企業会計    2011

  • The collective value: a new solution for games with coalition structures

    Yoshio Kamijo

    Top    2011

  • FARSIGHTED COALITIONAL STABILITY OF A PRICE LEADERSHIP CARTEL

    Yoshio Kamijo, Shigeo Muto

    JAPANESE ECONOMIC REVIEW   61 ( 4 ) 455 - 465  2010.12

     View Summary

    This paper analyzes the farsighted behaviour of firms that form a dominant price leadership cartel. We consider stability concepts such as the farsighted core, the farsighted stable sets, and the largest consistent set. We show that: (i) the farsighted core is either an empty set or a singleton set of the grand cartel; (ii) any Pareto efficient cartel is itself a farsighted stable set; and (iii) the set of cartels in which fringe firms enjoy higher profits than the firms in the minimal Pareto efficient cartel is the largest consistent set.

    DOI

  • FARSIGHTED COALITIONAL STABILITY OF A PRICE LEADERSHIP CARTEL

    Yoshio Kamijo, Shigeo Muto

    JAPANESE ECONOMIC REVIEW   61 ( 4 ) 455 - 465  2010.12

     View Summary

    This paper analyzes the farsighted behaviour of firms that form a dominant price leadership cartel. We consider stability concepts such as the farsighted core, the farsighted stable sets, and the largest consistent set. We show that: (i) the farsighted core is either an empty set or a singleton set of the grand cartel; (ii) any Pareto efficient cartel is itself a farsighted stable set; and (iii) the set of cartels in which fringe firms enjoy higher profits than the firms in the minimal Pareto efficient cartel is the largest consistent set.

    DOI

  • Axiomatization of the Shapley value using the balanced cycle contributions property

    Yoshio Kamijo, Takumi Kongo

    INTERNATIONAL JOURNAL OF GAME THEORY   39 ( 4 ) 563 - 571  2010.10

     View Summary

    This paper presents an axiomatization of the Shapley value. The balanced cycle contributions property is the key axiom in this paper. It requires that, for any order of all the players, the sum of the claims from each player against his predecessor is balanced with the sum of the claims from each player against his successor. This property is satisfied not only by the Shapley value but also by some other values for TU games. Hence, it is a less restrictive requirement than the balanced contributions property introduced by Myerson (International Journal of Game Theory 9, 169-182, 1980).

    DOI

  • 検索連動型広告オークションの最適広告枠数についての考察

    安達剛, 上條良夫

    日本オペレーションズ・リサーチ学会春季研究発表会アブストラクト集   2010   82 - 83  2010.03

    CiNii J-GLOBAL

  • 1-E-7 検索連動型広告オークションの最適広告枠数についての考察(ゲーム理論)

    安達 剛, 上條 良夫

    日本オペレーションズ・リサーチ学会春季研究発表会アブストラクト集   2010   82 - 83  2010.03

    CiNii

  • Dynamics, stability, and foresight in the Shapley-Scarf housing market

    Yoshio Kamijo, Ryo Kawasaki

    JOURNAL OF MATHEMATICAL ECONOMICS   46 ( 2 ) 214 - 222  2010.03

     View Summary

    While most of the literature starting with Shapley and Scarf (1974) have considered a static exchange economy with indivisibilities, this paper studies the dynamics of such an economy. We find that both the dynamics generated by competitive equilibrium and the one generated by the weak dominance relation, converge to a set of allocations we define as strictly stable, which we can show to exist. Moreover, we show that even when only pairwise exchanges between two traders are allowed, the strictly stable allocations are attained eventually if traders are sufficiently farsighted. (C) 2009 Elsevier B.V. All rights reserved.

    DOI

  • Dynamics, stability, and foresight in the Shapley-Scarf housing market

    Yoshio Kamijo, Ryo Kawasaki

    JOURNAL OF MATHEMATICAL ECONOMICS   46 ( 2 ) 214 - 222  2010.03

     View Summary

    While most of the literature starting with Shapley and Scarf (1974) have considered a static exchange economy with indivisibilities, this paper studies the dynamics of such an economy. We find that both the dynamics generated by competitive equilibrium and the one generated by the weak dominance relation, converge to a set of allocations we define as strictly stable, which we can show to exist. Moreover, we show that even when only pairwise exchanges between two traders are allowed, the strictly stable allocations are attained eventually if traders are sufficiently farsighted. (C) 2009 Elsevier B.V. All rights reserved.

    DOI

  • Axiomatization of the Shapley value using the balanced cycle contributions property

    Yoshio Kamijo, Takumi Kongo

    International Journal of Game Theory   39 ( 4 ) 563 - 571  2010

     View Summary

    This paper presents an axiomatization of the Shapley value. The balanced cycle contributions property is the key axiom in this paper. It requires that, for any order of all the players, the sum of the claims from each player against his predecessor is balanced with the sum of the claims from each player against his successor. This property is satisfied not only by the Shapley value but also by some other values for TU games. Hence, it is a less restrictive requirement than the balanced contributions property introduced by Myerson (International Journal of Game Theory 9, 169-182, 1980). © 2009 Springer-Verlag.

    DOI

  • A linear proportional effort allocation rule

    Yoshio Kamijo

    MATHEMATICAL SOCIAL SCIENCES   58 ( 3 ) 341 - 353  2009.11

     View Summary

    This paper proposes a new class of allocation rules in network games. Like the solution theory in cooperative games of how the Harsanyi dividend of each coalition is distributed among a set of players, this new class of allocation rules focuses on the distribution of the dividend of each network. The dividend of each network is allocated in proportion to some measure of each player&apos;s effort, which is called an effort function. With linearity of the allocation rules, an allocation rule is specified by the effort functions. These types of allocation rules are called linear proportional effort allocation rules. Two famous allocation rules, the Myerson value and the position value, belong to this class of allocation rules. In this study, we provide a unifying approach to define the two aforementioned values. Moreover, we provide an axiomatic analysis of this class of allocation rules, and axiomatize the Myerson value, the position value, and their non-symmetric generalizations in terms of effort functions. We propose a new allocation rule in network games that also belongs to this class of allocation rules. (C) 2009 Elsevier B.V. All rights reserved.

    DOI

  • A linear proportional effort allocation rule

    Yoshio Kamijo

    Mathematical Social Sciences   58 ( 3 ) 341 - 353  2009.11

     View Summary

    This paper proposes a new class of allocation rules in network games. Like the solution theory in cooperative games of how the Harsanyi dividend of each coalition is distributed among a set of players, this new class of allocation rules focuses on the distribution of the dividend of each network. The dividend of each network is allocated in proportion to some measure of each player's effort, which is called an effort function. With linearity of the allocation rules, an allocation rule is specified by the effort functions. These types of allocation rules are called linear proportional effort allocation rules. Two famous allocation rules, the Myerson value and the position value, belong to this class of allocation rules. In this study, we provide a unifying approach to define the two aforementioned values. Moreover, we provide an axiomatic analysis of this class of allocation rules, and axiomatize the Myerson value, the position value, and their non-symmetric generalizations in terms of effort functions. We propose a new allocation rule in network games that also belongs to this class of allocation rules. © 2009 Elsevier B.V. All rights reserved.

    DOI

  • Stable market structures from merger activities in mixed oligopoly with asymmetric costs

    Yoshio Kamijo, Yasuhiko Nakamura

    JOURNAL OF ECONOMICS   98 ( 1 ) 1 - 24  2009.09

     View Summary

    This paper examines endogenous merger formations in a mixed oligopoly. Applying the core as a solution concept, we analyze which market structure(s) remain(s) stable when three firms-two symmetric private firms and one inefficient public firm-are allowed to merge with each other in a mixed Cournot industry. We show that according to the value of the marginal cost of the public firm, there always exists a pair of share ratios of the owners of both the (pre-merged) public firm and the (pre-merged) private firm such that the market structure with the merger between the public firm and one private firm belongs to the core. When the initial market structure is a mixed triopoly, it can only be blocked when one public firm and one private firm merge. Furthermore, we conduct a similar analysis in a general mixed oligopoly with one public firm and n private firms.

    DOI

  • Stable market structures from merger activities in mixed oligopoly with asymmetric costs

    Yoshio Kamijo, Yasuhiko Nakamura

    JOURNAL OF ECONOMICS   98 ( 1 ) 1 - 24  2009.09

     View Summary

    This paper examines endogenous merger formations in a mixed oligopoly. Applying the core as a solution concept, we analyze which market structure(s) remain(s) stable when three firms-two symmetric private firms and one inefficient public firm-are allowed to merge with each other in a mixed Cournot industry. We show that according to the value of the marginal cost of the public firm, there always exists a pair of share ratios of the owners of both the (pre-merged) public firm and the (pre-merged) private firm such that the market structure with the merger between the public firm and one private firm belongs to the core. When the initial market structure is a mixed triopoly, it can only be blocked when one public firm and one private firm merge. Furthermore, we conduct a similar analysis in a general mixed oligopoly with one public firm and n private firms.

    DOI

  • A two-step shapley value for cooperative games with coalition structures

    Yoshio Kamijo

    International Game Theory Review   11 ( 2 ) 207 - 214  2009.06

     View Summary

    In this paper, we study cooperative games with coalition structures. We show that a solution concept that applies the Shapley value to games among and within coalitions and in which the pure surplus that the coalition obtains is allocated among the intra-coalition members in an egalitarian way, is axiomatized by modified axioms on null players and symmetric players and the usual three axioms: efficiency, additivity and coalitional symmetry. In addition to the original definition, we give two expressions of this solution concept. One is an average of modified marginal contributions and the other is the weighted Shapley value of a game with restricted communication. © 2009 World Scientific Publishing Company.

    DOI

  • Interregional mixed duopoly

    Tomohiro Inoue, Yoshio Kamijo, Yoshihiro Tomaru

    REGIONAL SCIENCE AND URBAN ECONOMICS   39 ( 2 ) 233 - 242  2009.03

     View Summary

    We investigate an interregional mixed duopoly wherein a local public firm competes against a private firm. We employ a spatial model with price competition. The public firm is owned by the local government of the left half of the linear city called Region 1, and maximizes its welfare. We demonstrate that our two-stage game comprising location choice and price competition has two types of equilibria. In one equilibrium (E(1)), the local public firm locates in Region 1, and the private firm locates outside the region. In the other equilibrium (E(2)), both firms are located in Region 1. We find that although the two firms are closely located in E(2), E(2) payoff-dominates E(1). Moreover, E(2) is robust in the sense that the sequential choice of location adopts this equilibrium, regardless of whether the public firm is a leader or a follower. (C) 2008 Elsevier B.V. All rights reserved.

    DOI

  • Interregional mixed duopoly

    Tomohiro Inoue, Yoshio Kamijo, Yoshihiro Tomohiro

    Regional Science and Urban Economics   38   233 - 242  2009

    DOI

  • A two-step Shapley value for cooperative games with coalition structures

    Yoshio Kamijo

    International Game Theory Review   11 ( 2 ) 207 - 214  2009

    DOI

  • Implementation of weighted values in hierarchical and horizontal cooperation structures

    Yoshio Kamijo

    Mathematical social sciences   56 ( 3 ) 336 - 349  2008.11

     View Summary

    This paper studies a non-cooperative mechanism implementing a cooperative solution for a situation in which members of a society are subdivided into groups and/or coalitions and there is asymmetry among the individuals of the society. To describe hierarchical and horizontal cooperation structure simultaneously, we present unified classes of games, the games with social structure, and define a weighted value for these games. We show that our mechanism works in any zero-monotonic environment and implements the Shapley value, the weighted Shapley value, the Owen's coalitional value, and the weighted coalitional value, in some special cases. © 2008 Elsevier B.V. All rights reserved.

    DOI

  • Implementation of weighed values in hierarchical and horizontal cooperation structures

    Yoshio Kamijo

    Mathematical Social Sciences   56   336 - 349  2008

    DOI

  • An implementation of the Owen's coalitional value: another approach

    上條 良夫

    早稲田経済学研究   ( 65 ) 21 - 39  2007.09

    CiNii

  • Public ownership of firms and intergovernmental competition

    井上 智弘, 上條 良夫, 都丸 善央

    早稲田経済学研究   65 ( 65 ) 1 - 20  2007.09

    CiNii

  • Voluntary contribution mechanism game and endogenous institution selection

    上條 良夫, 竹内 あい

    The Waseda journal of political science and economics   368 ( 368 ) 21 - 40  2007.07

    CiNii

  • An Endogenous Objective Function of a Partially Privatized Firm: A Nash Bargaining Approach

    上條良夫, 都丸善央

    日本経済学会    2007

  • Owen の coalitional value の遂行

    上條良夫

    早稲田大学経済学研究   65   21 - 39  2007

  • Implementation of the Shapley Value of Games with Coalition Structures

    Kamijo Yoshio

    The Waseda journal of political science and economics   363 ( 363 ) 105 - 125  2006

    CiNii

  • Implementation of the Shapley value of games with coalition structures

    Yoshio Kamijo

    The Waseda Journal of Political Science and Economics   363   105 - 125  2006

  • 提携構造付き特性関数形ゲームの S-S value の公理化(協力形成のゲーム理論分析)

    上條 良夫

    日本オペレーションズ・リサーチ学会春季研究発表会アブストラクト集   2004   306 - 307  2004.03

    CiNii

  • Stability and efficiency in the perfect foresight situation

    Yoshio Kamijo

    Theory and Decision   forthcoming

    DOI

  • Who will be Called Partner? A Public Firm's Incentive to Merge with Private Firms

    Yoshio Kamijo, Yasuhiko Nakamura, Yoshihiro Tomaru

    Waseda Journal of Political Science and Economics   forthcoming

  • Who will be Called Partner? A Public Firm's Incentive to Merge with Private Firms

    Yoshio Kamijo, Yasuhiko Nakamura, Yoshihiro Tomaru

    Waseda Journal of Political Science and Economics   forthcoming

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Syllabus

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Research Institute

  • 2023
    -
    2024

    Center for Data Science   Concurrent Researcher

  • 2022
    -
    2024

    Waseda Center for a Carbon Neutral Society   Concurrent Researcher

Internal Special Research Projects

  • 情報更新と情報開示行動の理論仮説の構築とシミュレーション分析

    2021  

     View Summary

    現代社会は情報が氾濫している。これらの情報の中には、情報発信者が意図せず発信してしまったもの出る場合もあるが、より重要と考えられ情報の多くは、誰かの意思によって公開するべきか否かを事前にスクリーニングされた結果である。本研究は、発信者が側の情報公開の有無に関わる意思決定および、受信者側の情報入手後の信念更新に関する経済学の理論的モデルを構築し、実験による検証を最終目標とするものである。本研究では、理論仮説の導出および理論仮説からシミュレートされたデータに対して統計分析を行い、必要な分析手法やデータサイズを検討し、外部研究費の応募の際の基礎資料として利用した。

  • 協力ゲームの解の考察:公理的接近と非協力ゲームによる接近

    2010  

     View Summary

     本研究では、協力ゲームの様々な解を公理的に分析するにあたり、Kamijo and Kongo (2010, IJGT) により提案された一つの公理に注目する。この公理は、Shapley value を公理化する性質としてよく知られた Balanced Contributions Property (BC) の要求を弱めた、Balanced Cycle Contributions Property (BCC) という公理である。BCC は、BC の要求する社会に存在する任意の二人において成立するある種の衡平関係ないし緊張関係を、社会を構成する全員の間で成立するような緩やかな衡平関係として描きなおすものである。協力ゲームの解の理論において、BC の要求を BCC へと弱めることの一つの利点は、BCC により Shapley value 以外の解も公理化できる可能性があることである。実際、BC と効率性を満足する解が Shapley value だけであるのに対して、BCC と効率性を満足するような解は無数に存在している。BCC と効率性に追加的な公理を付け加えることにより、Shapley value 以外の様々な解が公理化できることが期待されるのである。 本研究を通じて、上記のような予測が実際に成立することが確認された。つまり、BCC を用いることにより、CIS value、Egalitarian value, Solidarity value, Banzhaf value などの先行研究で提案されてきた解達を統一的に公理化することに成功したのである。さらに、加法性と対称性を満たすような解が必ず BCC を満たすという、BCC を満足するための十分条件も発見された。

  • 最終提案ゲームにおける役割決定手続きの影響について

    2007  

     View Summary

     本研究課題は,申請者が数年にわたり継続してきた,最終提案ゲームにおける役割決定手続きの被験者行動に及ぼす行動についての研究の中に位置づけられるものである。これまでの実験研究により,役割決定手続きが自己決定的であるような場合には,提案者は自身の立場に正当性を見出しより利己的な提案をするようになるようになり,応答者は提案者の立場の正当性を認め,提案者の利己的な提案を受け入れるようになる,ことが明らかにされた。本研究課題では,このような実験結果の頑健性を確認するために追実験を行ったのである。 追実験は,2007年の7月30,31日に早稲田大学の学生56人を被験者として実施した。実験内容は,ランダムに提案者・応答者の役割が決定される状況下で,応答者が棄却した際の提案者と応答者の利得に格差があるように設計された。このような設定での提案者行動,応答者行動を観察することにより、これまで得られた知見の頑健性について確認できるのである。実験は4セッション行われ、一セッションあたり1時間10分程度であった。 本研究内容については,2007年日本経済学会秋大会(共同研究者,竹内あい氏による報告)や第11回実験社会科学コンファランスにおいて報告され、日経学会報告時の討論者である広島大学の草川孝夫氏をはじめ,多くの方々からコメントをいただいた。これらのコメントを含めた論文の修正も終了し,現在は査読付き雑誌への投稿準備中である。