How Verifiable Cheap-Talk Can Communicate Unverifiable Information

This study describes a “cheap-talk” model in which sellers can credibly convey unverifiable information by choosing whether or not to exaggerate verifiable information. We find that unexaggerated claims can communicate favorable unverifiable information if buyers are not too likely to verify claims, and sellers with better information care more about future prices than sellers with worse information. However, there is always another equilibrium in which sellers exaggerate all verifiable claims. Laboratory tests show that when buyers infrequently verify the sellers' claims, players converge to the equilibria close to the example provided in instructions. When buyers are very likely to verify claims, players fail to converge to any equilibrium. Both of these results are consistent with an evolutionary learning model, but inconsistent with the intuitive criteria of Cho and Kreps (1987). We discuss the implications of our results for both consumer and financial markets. Helpful comments were received by an anonymous reviewer, Mark Nelson, many doctoral students at Cornell University, and Accounting workshop participants at the University of Texas at Austin. JEL Classification: C73, C92, G14, M3     

Harmful signaling in matching markets

Several labor markets, including the job market for new Ph.D. economists, have recently developed formal signaling mechanisms. We show that such mechanisms are harmful for some environments. While signals transmit previously unavailable information, they also facilitate information asymmetry that leads to coordination failures. In particular, we consider a two-sided matching game of incomplete information between firms and workers. Each worker has either the same “typical” known preferences with probability close to one or “atypical” idiosyncratic preferences with the complementary probability close to zero. Firms have known preferences over workers. We show that under some technical condition if at least three firms are responsive to some workerʼs signal, the introduction of signaling strictly decreases the expected number of matches.     

Subgame Perfect Equilibria in Stage Games

It is well known that a stage game with infinite choice-sets, unless it contains a public coordination-device in each stage, may have no subgame perfect equilibria. We show that if a game with public coordination-devices has a subgame perfect equilibrium in which two players in each stage use non-atomic strategies, then the game without coordination devices also has a subgame perfect equilibrium. Journal of Economic Literature Classification Numbers: C6, C7, D8.     

Communication in financial markets with several informed traders

This paper investigates the incentives for informed traders in financial markets to reveal their information truthfully to the public. In the model, a subset of traders receive noisy signals about the value of a risky asset. The signals are composed of a directional component (“high” vs. “low”) as well as a precision component that represents the quality of the directional component. Between trading periods, the informed agents make public announcements to the uninformed traders. With a sufficiently large number of informed traders, an equilibrium exists in which the directional components are credibly revealed, but not the precision components. Even though the informed traders retain some of their rivate information, the post-communication estimate of the asset value converges in probability to the full-information estimate as the number of informed traders increases. The paper is based on a chapter of my Ph.D. thesis at the University of Western Ontario and was circulated previously under the title “Public Communication Devices in Financial Markets.” I thank my dissertation committee Arthur Robson, Hari Govindan, and Al Slivinski for their guidance and support. I also thank Murali Agastya, Roland Benabou, Philippe Grégoire, Rick Harbaugh, Mike Peters, an anonymous referee and an associate editor, and seminar participants at various universities and conferences at which this paper was presented.     

Equilibrium selection in experimental cheap talk games

In the past, many refinements have been proposed to select equilibria in cheap talk games. Usually, these refinements were motivated by a discussion of how rational agents would reason in some particular cheap talk games. In this paper, we propose a new refinement and stability measure that is intended to predict actual behavior in a wide range of cheap talk games. According to our Average Credible Deviation Criterion (ACDC), the stability of an equilibrium is determined by the frequency and size of credible deviations. ACDC organizes the results from several cheap talk experiments in which behavior converges to equilibrium, even in cases where other criteria do not make a prediction.     

The estimated ex ante economic impact of Bt cowpea in Niger,Benin and Northern Nigeria

Genetically modified (GM) crops could increase economic growth and enhance living standards in Africa, but political issues have slowed the use of biotechnology. This is the first study that assesses the potential impact of GM crops in Africa while considering the preferences of producers and consumers towards GMOs as well as the income and price risks they face. The study uses a choice experiment to estimate the ex ante economic impact of a novel technology, Bacillus thuringiensis (Bt) cowpea, on producers and consumers in Benin, Niger and northern Nigeria. The experiment involves the simulation of a market transaction similar to those in open air markets in West Africa. During the market simulation, respondents are informed about the advantages and disadvantages, including health risks, of Bt cowpea. The results from the study suggest that cowpea growers and consumers in Benin and northern Nigeria prefer Bt to conventional cowpea for health safety reasons. The results estimate that social welfare in Benin, Niger and northern Nigeria would increase by at least US$11.82 per capita annually with Bt cowpea, if seed sectors are operating smoothly. With inefficiencies in seed sectors and the potential for cowpea acreage increase, the estimated social welfare increase in the region would be about US$1.26 per capita annually.     

论大学英语教学中的教师话语

教师话语对学生的语言输出、课堂参与度、学习态度及整个语言学习的过程有着极其深远的影响,本论文从教师话语的理论基础入手,谈论了大学英语中教师话语的现状以及改进措施。     

Language and tourism

The sociolinguistic study of verbal encounters in touristic situations provides an opportunity to exanine communication between different linguistic groups under unusual circumstances: the high temporariness of the foreigners and the high degree of linguistic accommodation of the locals to them. This state of affairs stands in marked contrast to the tendency of guestworkers and immigrants who are less temporary and usually of lower status, to accommodate linguistically to the locals. While accommodation by locals is common to virtually all touristic situations, the degree of proficiency of locals in the tourists' language varies considerably and hence also the extent to which tourists are forced to accommodate linguistically. In an effort to organize the linguistic variation in tourism, a typology of tourist roles is used as the principal framework. The notion of “language brokerage” is introduced. The integration of sociological and sociolinguistic analyses is illustrated by incidental data from the literature on tourism and from fieldwork in Thailand.     

厉行节约形势下中国星级饭店的发展及对策研究

在"厉行节约,反对浪费"的形势下,星级饭店面临着重新洗牌的风险。五星级饭店应及时调整策略,转变经营模式,做好转型升级,中低档饭店应抓住机遇,加强品牌管理,提高信息化水平。     

大学英语课堂教师话语分析

教师话语具有双重作用,一方面它是教师传授知识的媒介,另外一方面它作为目的语起着示范作用。因而,国内外今年来有越来越多的学者开始关注教师的话语,分析其数量和质量与课堂教学效果的关系。针对大学英语课堂这一特殊而又关键的场所,对教师的话语从语言的调整、教师提问、学生的反馈作了介绍。除此以外,针对教师话语存在的问题,提出应当从课堂,语言能力的角度提升话语质量从而有效利用好课堂的宝贵时间。