We report results from standard minimum-effort experiments conducted in Copenhagen (Denmark). Our subjects frequently coordinate on the Pareto-efficient equilibrium even in groups of six. This is in stark contrast to the previous literature, as we show in a detailed analysis of experiments which had the same design but were held in different countries. The subject-pool effect is substantiated by the finding that, the higher the share of Danish subjects in a group, the higher the minimum-effort levels. These findings suggest that the prevalent coordination failures previously observed are affected by significant subject-pool effects.

This paper examines the occurrence and fragility of information cascades in two laboratory experiments. One group of low informed participants sequentially guess which of two states has been randomly chosen. In a matched pairs design, another group of high informed participants make similar guesses after having observed the guesses of the low informed participants. In the second experiment, participants’ beliefs about the chosen state are elicited. In equilibrium, low informed players who observe an established pattern of identical guesses herd without regard to their private information whereas high informed players always guess according to their private information. Equilibrium behavior implies that information cascades emerge in the group of low informed participants, the belief based solely on cascade guesses is stationary, and information cascades are systematically broken by high informed participants endowed with private information contradicting the cascade guesses. Experimental results show that the behavior of low informed participants is qualitatively in line with the equilibrium prediction. Information cascades often emerge in our experiments. The tendency of low informed participants to engage in cascade behavior increases with the number of identical guesses. Our main finding is that information cascades are not fragile. The behavior of high informed participants differs markedly from the equilibrium prediction. Only one-third of laboratory cascades are broken by high informed participants endowed with private information contradicting the cascade guesses. The relative frequency of cascade breaks is 15% for the situations where five or more identical guesses are observed. Participants’ elicited beliefs are strongly consistent with their own behavior and show that, unlike in equilibrium, the more cascade guesses participants observe the more they believe in the state favored by those guesses.

We study with the help of a laboratory experiment the conditions under which an uninformed manipulator—a robot trader that unconditionally buys several shares of a common value asset in the beginning of a trading period and unwinds this position later on—is able to induce higher asset prices. We find that the average price is significantly higher in the presence of the manipulator if and only if the asset takes the lowest possible value and insiders receive perfect information about the true value of the asset. It is also evidenced that the robot trader makes trading gains. Finally, both uninformed and partially informed traders may suffer from the presence of the robot.

This paper reports a new and significant experimental demonstration that market participants adjust their bids towards the price observed in previous market periods when—by design—individuals’ values should not be affiliated with the market price. This demonstration implies that market prices may not adjust as standard comparative statics predicts and emphasizes the significance of social aspects even in market contexts. Hence, the present study shows that market behaviour is not anomaly-free. Indeed, market behaviour does not reveal the underlying true preferences but rather context-dependent preferences.

We experimentally test monetary policy decision making in a population of inexperienced central bankers. In our experiments, subjects repeatedly set the short-term interest rate for a computer economy with inflation as their target. A large majority of subjects learn to successfully control inflation by correctly putting higher weight on inflation than on the output gap. In fact, the behavior of these subjects meets a stability criterion. The subjects smooth the interest rate as the theoretical literature suggests they should in order to enhance stability of the uncertain system they face. Our study is the first to use Taylor-type rules as a framework to identify inflation weighting, stability, and interest-rate smoothing as behavioral outcomes when subjects try to achieve an inflation target.

We run an experiment in which students of different European nationalities are matched in groups of five and repeatedly choose with whom within their group they want to play a trust game. Participants observe of each other age, gender, nationality and number of siblings. The region of origin, “North” or “South” is a major determinant of success in the experiment. Participants tend to trust those they trusted before and who trusted them. We do not find evidence of regional discrimination per se. It is only the underlying and significant differences in behavior that translate through repeated interactions into differences in payoffs between the two regions.

Preferences for charitable giving in auctions can be modeled by assuming that bidders receive additional utility proportional to the revenue raised by an auctioneer. The theory of bidding in the presence of such preferences results in a very counterintuitive prediction which is that, in many cases, bidders having preferences for charitable giving does not lead to a substantial revenue advantage for an auctioneer. We test this theory and this prediction with a series of experiments. In one experiment we induce charitable preferences exactly as specified in the model to see if bidders respond to them as predicted. We find that they do. We then conduct a second experiment in which the revenue from the auctions is donated to actual charities to verify the robustness of the prediction when charitable preferences are generated by a more natural source and find again that the theoretical prediction holds: even strong charitable preferences do not result in substantial revenue increases to the auctioneer.

Experimental and empirical evidence highlights the role of networks on social outcomes. This paper tests the properties of exogenously fixed networks in team production. Subjects make the same decisions in a team work environment under four different organizational networks: the line, the circle, the star, and the complete network. In all the networks, links make information available to neighbors. This design allows us to analyze decisions across networks and a variety of subject types in a standard linear team production game. Contribution levels differ significantly across networks and the star is the most efficient incomplete network. Moreover, our results suggest that subjects act as conditional cooperators with respect to the information received from the network.

We review bubble measures which are commonly used in the experimental asset market literature. It seems sensible to require that measures of mispricing should (i) relate the fundamental value and price, (ii) be monotone in the difference between fundamental value and price, and (iii) be independent of the total number of periods and the absolute level of fundamental value. We show that none of the measures currently used fulfills all these criteria. To facilitate comparability across different experimental settings with different parameterizations we propose two alternative measures which fulfill all evaluation criteria. The measure for mispricing, RAD (relative absolute deviation), is calculated by averaging absolute differences between the (volume-weighted) mean price and the fundamental value across all periods and normalizing it with the absolute value of the average FV of the market. The measure for overvaluation, RD (relative deviation), is calculated analogously, but uses raw difference between (volume-weighted) mean prices and fundamental values. Hence, it provides information on whether the mispricing stems from over- or undervaluation of the asset.

Belief-elicitation experiments usually reward accuracy of stated beliefs in addition to payments for other decisions. But this allows risk-averse subjects to hedge with their stated beliefs against adverse outcomes of the other decisions. So can we trust the existing belief-elicitation results? And can we avoid potential hedging confounds? We propose an experimental design that theoretically eliminates hedging opportunities. Using this design, we test for the empirical relevance of hedging effects in the lab. Our results suggest that hedging confounds are not a major problem unless hedging opportunities are very prominent. If hedging opportunities are transparent, and incentives to hedge are strong, many subjects do spot hedging opportunities and respond to them. The bias can go beyond players actually hedging themselves, because some expect others to hedge and best respond to this.

We study the effects of price signaling activity and underlying propensities to cooperate on tacit collusion in posted offer markets. The primary experiment consists of an extensively repeated baseline sequence and a ‘forecast’ sequence that adds to the baseline a forecasting game that allows identification of signaling intentions. Forecast sequence results indicate that signaling intentions differ considerably from those that are counted under a standard signal measure based on previous period prices. Nevertheless, we find essentially no correlation between either measure of signal volumes and collusive efficiency. A second experiment demonstrates that underlying seller propensities to cooperate more clearly affect collusiveness.

Veto power consists of the right of one or more players to unilaterally block decisions but without the ability to unilaterally secure their preferred outcome. Our experiment shows that (i) committees with a veto player take longer to reach decisions (are less efficient) and generate less consensus than without a veto player, (ii) veto power substantially enhances proposer's power, and (iii) non-veto players are substantially more willing to compromise than veto players. We relate our results to the theoretical literature on the impact of veto power as well as to concerns about the impact of veto power in real-life committees.

This paper reports an experiment designed to shed light on an empirical puzzle observed by Dufwenberg and Gneezy (Games and Economic Behavior 30:163-182, 2000) that the size of the foregone outside option by the first mover does not affect the behavior of the second mover in a lost wallet game. Our conjecture was that the original protocol may not have made the size of the forgone outside option salient to second movers. Therefore, we change two features of the Dufwen- berg and Gneezy protocol: (i) instead of the strategy method we implement a direct response method (sequential play) for the decision of the second mover; and (ii) we use paper money certificates that are passed between the subjects rather than having subjects write down numbers representing their decisions. We observe that our procedure yields qualitatively the same result as the Dufwenberg and Gneezy experiment, i.e., the second movers do not respond to the change in the outside option of the first movers.

This paper reports the results of an experiment designed to study how subjects’ decision making may be affected by the timing of participation payments (or show-up fees). The experiment follows Davis et al. (J. Econ. 30:69-95, 2004) where subjects were asked to make a sequential purchase decision and were given the opportunity to purchase information about the value of a good prior to a decision to purchase the good itself. There, subjects purchased information less often than expected which was interpreted as risk-seeking behavior. Here, we test a payment hypothesis by varying the timing of the participation payment. Payment of a show-up fee before the decision-making stages of the experiment increases information purchase, which we interpret as an increase in risk-averse behavior.

The paper analyzes the effects of more intense competition on firms’ investments in process innovations. More intense competition corresponds to an increase in the number of firms or a switch from Cournot to Bertrand competition. We carry out experiments for two-stage games, where R&D investment choices are followed by product market competition. An increase in the number of firms from two to four reduces investments, whereas a switch from Cournot to Bertrand increases investments, even though theory predicts a negative effect in the four-player case. The results arise both in treatments in which both stages are implemented and in treatments in which only one stage is implemented. However, the positive effect of moving from Cournot to Bertrand competition is more pronounced in the former case.

Employing a two-by-two factorial design that manipulates whether dictator groups are single or mixed-sex and whether procedures are single or double-blind, we examine gender effects in a standard dictator game. No gender effects were found in any of the experimental treatments for the mean or median levels of giving, or for the propensity to give nothing. However, females chose to give away half of their endowments with greater frequency than males in the pooled single-sex treatments.

Game theory predicts that players make strategic commitments that may appear counter-intuitive. We conducted an experiment to see if people make a counter-intuitive but strategically optimal decision to avoid information. The experiment is based on a sequential Nash demand game in which a responding player can commit ahead of the game not to see what a proposing player demanded. Our data show that subjects do, but only after substantial time, learn to make the optimal strategic commitment. We find only weak evidence of physical timing effects.

Experimenter demand effects refer to changes in behavior by experimental subjects due to cues about what constitutes appropriate behavior. We argue that they can either be social or purely cognitive, and that, when they may exist, it crucially matters how they relate to the true experimental objectives. They are usually a potential problem only when they are positively correlated with the true experimental objectives’ predictions, and we identify techniques such as non-deceptive obfuscation to minimize this correlation. We discuss the persuasiveness or otherwise of defenses that can be used against demand effects criticisms when such correlation remains an issue.

Three experiments are designed to test if the level of irrelevant prizes in the menu has a positive (assimilation) or negative (contrast) effect on the perceived valuation of target objects. Familiar field prizes and binary lotteries over such prizes are placed within “more-expensive” and “less-expensive” menus. Subjects fill-in a sequence of binary choice problems to reveal their preference between given cash and a designated prize from the menu. Between-subject comparisons reveal that the prize-level in the menu positively affects perceived valuations in spite of procedural attempts to rule out menu-dependent preferences and prohibit experimenter bias. The effect also shows within-subject in auction experiments: the price that subjects are willing to pay for given monetary lotteries significantly increases with the average payoff in the irrelevant-menu. The bias finally manifests even when subjects are led to choose the target lottery, independently, from the underlying menu.

This paper introduces a mixture model based on the beta distribution, without pre-established means and variances, to analyze a large set of Beauty-Contest data obtained from diverse groups of experiments (Bosch-Domènech et al. 2002). This model gives a better fit of the experimental data, and more precision to the hypothesis that a large proportion of individuals follow a common pattern of reasoning, described as Iterated Best Reply (degenerate), than mixture models based on the normal distribution. The analysis shows that the means of the distributions across the groups of experiments are pretty stable, while the proportions of choices at different levels of reasoning vary across groups.