Some Strategic Aspects of Private Information: An Experimental Study

Date: 2016-04-20
By: Andrés Salamanca Lugo (TSE – Toulouse School of Economics – Toulouse School of Economics)
Olga Manrique Chaparro (Universidad Nacional de Colombia [Bogotá])
In this paper we experimentally analyze the use of private information in a class of zero-sum repeated games with incomplete information on one side and perfect monitoring. We analyze whether the information disclosure by the informed players, and its use by the uninformed players, matches the theoretical predictions. We consider two games that differ according to the amount of information that the informed player should optimally disclose: in the first game, the informed player should entirely conceal his information. In contrast, in the second game the informed player should fully disclose his information. We find that the flow of information is higher than predicted in the first game and lower than predicted in the second game. However, the use of information is strictly higher in the second game than in the first one. Uninformed subjects tend not to use the revealed information in the first game, and seem to misinterpret the revealed information in the second game.
Keywords: Repeated games,incomplete information,experiments

Firm-Specific Information and Explicit Collusion in Experimental Oligopolies

Firm-Specific Information and Explicit Collusion in Experimental Oligopolies
Date: 2015-05-10
By: Francisco Gomez-Martin (University of Amsterdam)
Sander Onderstal (University of Amsterdam)
Joep Sonnemans (University of Amsterdam)
We experimentally study the effect of information about competitors’ actions on cartel stability and firms’ incentives to form cartels in Cournot markets. As in previous experiments, markets become very competitive when individualized information is available and participants cannot communicate. In contrast, when communication is possible, results reverse: Markets become less competitive and cartels become more stable when individualized information is available. We also observe that the extra profits that firms obtain thanks to the possibility to communicate are higher when individualized information is present, suggesting that firms have greater incentives to form cartels in that situation.
Keywords: Cournot oligopoly; Cartels; Information; Experiments
JEL: C92 L13 L41

An Experimental Study of Persuasion Bias and Social Influence in Networks

==Noted by yinung==
這篇和我之前的想法有點像, 不同處在於, 我是以小團體 (例如委員會) 中的資訊發表 (或擴散) 模式來探討, 並以多數決、一致決、不同意見發表能見度機率…來建構實驗; 這篇則是以連結數為主的設計 (比較適合一般網路世界)。
突然產生一個研究想法, 若 one of the committee members 想要增加他自已的影響力, 他才有過度發表 (宣傳) 他的意見的動機; 故在實驗設計中:
1. 每個 agent 有自已的 private signals (各有準確的機率), 或某些人還有 public reputation (比自己的 private signal 準確率高/低)
2. 每個 agent 動機都是為 group 好 / 加入 agent 自已的 utility, 認同他的人愈多, 則 utility 愈大)
3. 這個特別的 agent 可能是經理, 主席, 社團領袖, 只是普通的組員 (強調不同決策形成模式)
    經理: 獨裁但負全責
    主席: 多數決, 責任分擔
    社團領袖: 共識決, , 責任分擔
    普通組員: 非意見領袖
Date: 2014-10
By: Jordi Brandts (Institutd’AnalisiEconomica(CSIC))
Ayça Ebru Giritligil (Murat Sertel Center for Advanced Economic Studies)
Roberto A. Weber (Department of Economics, University of Zurich)
In many areas of social life individuals receive information about a particular issue of interest from multiple sources. When these sources are connected through a network then proper aggregation of this information by an individual involves taking into account the structure of this network. The inability to aggregate properly may lead to various types of distortions. In our experiment a number of agents all want to find out the value of a particular parameter unknown to all. Agents receive private signals about the parameter and agents can communicate their estimates of the parameter repeatedly through a network, the structure of which is known by all players. We present results from experiments with four different networks. We find that the information of agents who have more outgoing links in a network gets more weight in the information aggregation of the other agents than it optimally should. Our results are consistent with the model of “persuasion bias” of De Marzo et al. (2003) and at odds with an alternative heuristic according to which the most influential agents are those with more incoming links.

Facts and Figuring: An Experimental Investigation of Network Structure and Performance in Information and Solution Spaces

Date: 2014-03
By: Jesse Shore (Boston University – Department of Information Systems)
Ethan Bernstein (Harvard Business School, Organizational Behavior Unit)
David Lazer (Harvard University – Harvard Kennedy School (HKS))
Using data from a novel laboratory experiment on complex problem solving in which we varied the network structure of 16-person organizations, we investigate how an organization’s network structure shapes performance in problem-solving tasks. Problem solving, we argue, involves both search for information and search for solutions. Our results show that the effect of network structure is opposite for these two important and complementary forms of search. Dense clustering encourages members of a network to generate more diverse information, but discourages them from generating diverse theories: in the language of March (1991), clustering promotes exploration in information space, but decreases exploration in solution space. Previous research, generally focusing on only one of those two spaces at a time, has produced inconsistent conclusions about the value of network clustering. By adopting an experimental platform on which information was measured separately from solutions, we were able to reconcile past contradictions and clarify the effects of network clustering on problem-solving performance. The finding both provides a sharper tool for structuring organizations for knowledge work and reveals the challenges inherent in manipulating network structure to enhance performance, as the communication structure that helps one antecedent of successful problem solving may harm the other.
Keywords: networks, experiments, clustering, problem solving, exploration and exploitation, knowledge, information, communication, search

When Identifying Contributors is Costly: An Experiment on Public Goods

Date: 2014
By: Anya Savikhin Samek (School of Human Ecology, University of Wisconsin-Madison)
Roman M. Sheremeta (Weatherhead School of Management, Case Western Reserve University and the Economic Science Institute, Chapman University,)
Studies show that identifying contributors significantly increases contributions to public goods. In practice, however, viewing identifiable information is costly, which may discourage people from accessing such information. To address this question, we design a public goods experiment in which participants can pay a fee to view information about identities and corresponding contributions of their group members. We then compare this to a treatment in which there is no identifiable information, and a treatment in which all contributors are freely identified. Our main findings are that: (1) contributions in the treatment with costly information are as high as those in the treatment with free information, (2) participants choose to view the information about 10% of the time, and (3) being a high contributor is positively correlated with choosing to view identifiable information about others. Thus, it seems that having access to information is important even when such information is rarely viewed. Or findings have practical implications for non-profit organizations with a large pool of donors and for designers of recognition systems, especially in online communities with many participants.
Keywords: public-goods, information, experiments
JEL: C72 C91 H41

Information and consumer fraud in a signalling model

Date: 2014-01
By: Silvia Martínez-Gorricho (Dpto. Análisis Económico Aplicado)
This article considers a two-sided private information model. We assume that two exogenously given qualities are offered in a monopolistic market. Prices are fixed. A low quality seller chooses to be either honest (by charging the lower market price) or dishonest (by charging the higher price). We discuss the signaling role of the consumer’s private information on the equilibrium level of dishonesty, incidence of fraud and trade. We demonstrate that the equilibrium incidence of fraud is nonmonotonic in the buyer’s private information when the prior belief favors the low-quality seller strongly enough. This result holds as long as information is noisy and regardless of its private or public nature. Welfare consequences are ambiguous.
Keywords: Consumer Fraud; Asymmetric Information; Price Signalling
JEL: D42 D82 G14 L15 L51

Balancing the Power to Appoint Officers

Date: 2013-05
By: Salvador Barberà
Danilo Coelho
Rules of k names are frequently used methods to appoint individuals to office. They are two-stage procedures where a first set of agents, the proposers, select k individuals from an initial set of candidates, and then another agent, the chooser, appoints one among those k in the list. In practice, the list of k names is often arrived at by letting each of the proposers screen the proposed candidates by voting for v of them and then choose those k with the highest support. We then speak of v-rules of k names. Our main purpose in this paper is to study how different choices of the parameters v and k affect the balance of power between the proposers and the choosers. From a positive point of view, we analyze a strategic game where the proposers interact to determine what list of candidates to submit. From a normative point of view, we study the performance of different rules in expected terms, under different informational assumptions. The choice of v and k is then analyzed from the perspectives of efficiency, fairness and compromise.
Keywords: voting rules, constitutional design, Strong Nash equilibrium, rule of k names
JEL: D02

Rational Expectations and the Aggregation of Diverse Information in Laboratory Security Markets

Charles R. Plott and Shyam Sunder (1988) “Rational Expectations and the Aggregation of Diverse Information in Laboratory Security Markets." Econometrica, Vol. 56, No. 5 (Sep., 1988), pp. 1085-1118. Article Stable URL:; 提供的 [PDF].

==original Abstract==

The idea that markets might aggregate and disseminate information and also resolve conflicts is central to the literature on decentralization (Hurwicz, 1972) and rational expectations (Lucas, 1972). We report on three series of experiments all of which were predicted to have performed identically by the theory of rational expectations. In two of the three series (one in which participants trade a complete set of Arrow-Debreu securities and a second in which all participants have identical preferences), double auction trading leads to efficient aggregation of diverse information and rational expectations equilibrium. Failure of the third series to exhibit such convergence demonstrates the importance of market institutions and trading instruments in achievement of equilibrium.

Groups Make Better Self-Interested Decisions

Gary Charness and Matthias Sutter (2012) “Groups Make Better Self-Interested Decisions." Journal of Economic Perspectives, 26(3): 157-76. DOI: 10.1257/jep.26.3.157; URL: AEAWeb. PDF1; PDF2

==Notes by yinung==


從賽局理論的角度看, 集體決策較個人決策來得理性 (rational), 因其可避免認知錯誤與限制。

不過集體決策也因此不見得會提高社會福利 (集體決策比較 self-interest)


the optimal size of the group ( A useful starting point here is Forsyth’s (2006) work)

==original Abstract==

In this paper, we describe what economists have learned about differences between group and individual decision-making. This literature is still young, and in this paper, we will mostly draw on experimental work (mainly in the laboratory) that has compared individual decision-making to group decision-making, and to individual decision-making in situations with salient group membership. The bottom line emerging from economic research on group decision-making is that groups are more likely to make choices that follow standard game-theoretic predictions, while individuals are more likely to be influenced by biases, cognitive limitations, and social considerations. In this sense, groups are generally less “behavioral" than individuals. An immediate implication of this result is that individual decisions in isolation cannot necessarily be assumed to be good predictors of the decisions made by groups. More broadly, the evidence casts doubts on traditional approaches that model economic behavior as if individuals were making decisions in isolation.


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==cited by==

1. Ananish Chaudhuri, Tirnud Paichayontvijit, Lifeng Shen. 2012. Gender differences in trust and trustworthiness: Individuals, single sex and mixed sex groups. Journal of Economic Psychology.