Volker Benndorf

Assistant professor for applied microeconomics · Goethe-University Frankfurt · benndorf@econ.uni-frankfurt.de

I am a researcher in experimental economics striving for a career in academia. My research interests include but are not limited to behavioral economics, experimental economics, game theory, privacy, industrial organization, individual decision making, group behavior.

Currently, I am an assitant professor at the department of Management and Microeconomics at Goethe-University Frankfurt, and an associate director of Frankfurt Laboratory for Experimental Economic Research (FLEX). Before joining Goethe-University in early 2017, I was a post-doctoral researcher and lab manager at the Düsseldorf Institute for Competiton Economics (DICE) at Heinrich-Heine-University Düsseldorf where I had completed my Ph. D. in December 2014.


Publications

Equilibrium selection with coupled populations in hawk–dove games: Theory and experiment in continuous time

Volker Benndorf, Ismael Martínez-Martínez, and Hans-Theo Normann, Journal of Economic Theory, 165 (2016): 472–486.

Abstract: Standard one- and two-population models for evolutionary games are the limit cases of a uniparametric family combining intra- and intergroup interactions. Our setup interpolates between both extremes with a coupling parameter κ. For the example of the hawk–dove game, we analyze the replicator dynamics of the coupled model. We confirm the existence of a bifurcation in the dynamics of the system and identify three regions for equilibrium selection, one of which does not appear in common one- and two-population models. We also design a continuous-time experiment, exploring the dynamics and the equilibrium selection. The data largely confirm the theory.

Privacy concerns, voluntary disclosure of information, and unraveling: An experiment

Volker Benndorf, Dorothea Kübler, and Hans-Theo Normann, European Economic Review, 75 (2015): 43–59.

Abstract: We study the voluntary revelation of private information in a labor-market experiment where workers can reveal their productivity at a cost. While rational revelation improves a worker׳s payoff, it imposes a negative externality on others and may trigger further revelation. Such unraveling can be observed frequently in our data although less often than predicted. Equilibrium play is more likely when subjects are predicted to conceal their productivity than when they should reveal. This tendency of under-revelation, especially of low-productivity workers, is consistent with the level-k model. A loaded frame where the private information concerns the workers׳ health status leads to less revelation than a neutral frame.

Gender differences in motivational crowding out of work performance

Volker Benndorf, Holger A. Rau, and Christian Sölch, Economic Inquiry, 57 (2019): 206–226.

Abstract: This paper shows that prior financial incentives induce a crowding‐out effect when incentives are discontinued. In our real‐effort experiment workers receive a piece rate before monetary incentives are substituted by a one‐time payment. In this case, workers' performance significantly drops when receiving the one‐time payment. The effect is driven by a fraction of men who reduce effort substantially, whereas women constantly perform well. We find that this motivational crowding‐out effect disappears when men do not have prior experience of a piece rate. In a series of control treatments, we discard several alternative explanations besides motivational crowding out.

Loss-induced emotions and criminal behavior: An experimental analysis

Florian Baumann, Volker Benndorf, and Maria Friese, Journal of Economic Behavior & Organization, 159 (2019): 134–145.

Abstract: We analyze the influence of frustration and anger on committing a norm violation in a laboratory experiment. Subjects complete a real-effort task where compensation is framed as a gain or a loss and subsequently report experienced levels of different emotions. Finally, subjects may increase their own income by taking away money designated for donation to charity. While both males and females experience higher levels of negative emotions in the loss frame than in the gain frame, we find that only men are more likely to take away money in the loss scenario.

Minimizing Learning Behavior in Repeated Real-Effort Tasks

Volker Benndorf, Holger Rau, and Christian Sölch, Journal of Behavioral and Experimental Finance, 22 (2019): 239–248.

Abstract: In this paper, we discuss learning behavior and the heterogeneity of subjects' ability to perform in real-effort tasks. Afterwards, we present a novel variant of Erkal et al.'s (2011) encryption real-effort task which aims to minimize learning behavior in repeated settings. In the task, participants encrypt words into numbers. In our variant, we apply a double-randomization mechanism to minimize learning and heterogeneity. Existing experiments with repeated real-effort tasks find a performance increase of 12-14% between the first and second half. By contrast, our task mitigates learning behavior down to 2% between the first and second half. The data show that subjects show a small heterogeneity in performance.

Voluntary disclosure of private information and unraveling in the market for lemons: An experiment

Volker Benndorf, Games, 9 (2018): 23.

Abstract: We experimentally analyze a lemons market with a labor-market framing. Sellers are referred to as “workers” and have the possibility to provide “employers” with costly but credible information about their “productivity”. Economic theory suggests that in this setup, unraveling takes place and a number of different types are correctly identified in equilibrium. While we do observe a substantial degree of information disclosure, we also find that unraveling is typically not as complete as predicted by economic theory. The behavior of both workers and employers impedes unraveling in that there is too little disclosure. Workers are generally reluctant to disclose their private information, and employers enforce this behavior by bidding less competitively if workers reveal compared to the case where they conceal information.

The willingness to sell personal data

Volker Benndorf and Hans-Theo Normann, Scandinavian Journal of Economics, 120 (2018): 1260–1278.

Abstract: We assess the willingness of individuals to sell personal data in laboratory experiments. Our experiments are novel in that they are incentivized, the focus on privacy issues is salient, and the use of the data is transparent and unambiguous. We find considerable heterogeneity in the data. Roughly one in six participants refuse to sell personal data at all and a similar fraction sell their data for 2.50 euros or less. Our results contrast with those from hypothetical questionnaires. Those willing to sell, request, on average, 15 euros for their contact details and 19 euros for their Facebook data.

Experienced vs. inexperienced participants in the lab: do they behave differently?

Volker Benndorf, Claudia Moellers, and Hans-Theo Normann, Journal of the Economic Science Association, 3 (2017): 12–25.

Abstract: We analyze whether subjects with extensive laboratory experience and first-time participants, who voluntarily registered for the experiment, differ in their behavior. Subjects play four one-shot, two-player games: a trust game, a beauty contest, an ultimatum game, a traveler’s dilemma and, in addition, we conduct a single-player lying task and elicit risk preferences. We find few significant differences. In the trust game, experienced subjects are less trustworthy and they also trust less. Furthermore, experienced subjects submit fewer non-monotonic strategies in the risk elicitation task. We find no differences whatsoever in the other decisions. Nevertheless, the minor differences observed between experienced and inexperienced subjects may be relevant because we document a potential recruitment bias: the share of inexperienced subjects may be lower in the early recruitment waves.

Depth of reasoning and information revelation: An experiment on the distribution of k-Levels

Volker Benndorf, Dorothea Kübler, and Hans-Theo Normann, International Game Theory Review, 19 (2017): 1750021.

Abstract: The level-k model is a workhorse in behavioral game theory. For comparisons across experiments and predictions in future studies, it is crucial to assess the empirical distribution of k-levels. We present a revelation game suitable for this purpose. In a labor market context, workers can choose to reveal their productivity at a cost, and players’ strategies reveal their level of reasoning in terms of a k-level. We find that the most frequently observed reasoning levels are k=2 and k=3. In our game roughly 30% of the players are k≤1 and 25% are k≥4. We compare our results to other experiments that identify level-k distribution, foremost to the money request (or 11–20) game. Despite various differences to the 11–20 game, our revelation game suggests a very similar distribution of level-k types.

Perturbed best response dynamics in a hawk–dove game

Volker Benndorf and Ismael Martínez-Martínez, Economics Letters, 165 (2016): 472–486.

Abstract: We examine the impact of behavioral noise on equilibrium selection in a hawk–dove game with a model that linearly interpolates between the one- and two-population structures in an evolutionary context. Perturbed best response dynamics generates two hypotheses in addition to the bifurcation predicted by standard replicator dynamics. First, when replicator dynamics suggests mixing behavior (close to the one-population model), there will be a bias against hawkish play. Second, polarizing behavior as predicted by replicator dynamics in the vicinity of the two-population model will be less extreme in the presence of behavioral noise. We find both effects in our data set.


Working papers

An Experiment on Partial Cross-Ownership in Oligopolistic Markets

Volker Benndorf and Johannes Odenkirchen.

Abstract: We examine coordinated and unilateral effects of horizontal partial cross-ownership (PCO) in a laboratory experiment. Firms have symmetric, non-controlling shares of each other in a static and a repeated Bertrand setting. The data of the dynamic game confirm the prediction and show that firms are more (tacitly) collusive with PCO than without. In the static game, higher degrees of PCO make firms behave less competitively. The observed higher average prices in the one-shot games are inconsistent with standard Nash predictions. A model with bounded rationality shows that firms' incentives to compete are reduced with passive PCO.

Games With Coupled Populations: An Experiment in Continuous Time

Volker Benndorf, Ismael Martı́nez-Martı́nez, and Hans-Theo Normann.

Abstract: We propose a model of coupled population games where intra- and intergroup interactions overlap. We analyze the general class of symmetric 2x2 games with coupled replicator dynamics. Standard one- and two-population predictions extend to a total of ten regions with different sets of attractors, among them novel hybrid points where one population randomizes and the other plays a pure strategy. Building on the theoretical analysis, we run continuous-time laboratory experiments using 48 different variants of coupled games. Observations confirm the theory to a large extent, but we also find a number of systematic deviations. When the attractors' eigenvalues are smaller (in absolute terms), play converges to steady states located further from the prediction.

Experience

Goethe-University Frankfurt

Assistant professor for applied microeconomics
Associate Director of the Frankfurt Laboratory for experimental Economic Research (FLEX)
since Feb. 2017

Heinrich-Heine-University Düsseldorf

Post-doc and coordinator of the graduate school (DFG GRK 1974)
Head of the DICE Laboratory for experimental economics
Sep. 2014 - Feb. 2017

Heinrich-Heine-University Düsseldorf

Ph.D. student and head of the DICE Laboratory for experimental economics
May 2010 - Sep. 2014

Education

Heinrich-Heine University Düsseldorf

Ph. D. in Economics
2010 - 2014

Ruprecht-Karls-University Heidelberg

Diploma in Economics
2003 - 2009

Awards & Grants

  • Prize for the best dissertation (awarded by the Goethe bookstore Düsseldorf)