Tilman Fries

Assistant Professor

LMU Munich



Picture credits: Jeanna Kolesova

About me

I am a microeconomist, with a focus on behavioral and experimental economics. My current research focuses on how belief-based utility impacts strategic decision making and belief formation.

You can find my CV here.

In Progress

Priors and prejudice  

(Abstract) Social media and internet search engines give easy access to information about others. This paper studies the behavioral consequences when individuals learn more about others they interact with. In principle, as observers learn about decision makers, this limits the ability of decision makers to signal their type through their actions. I provide experimental evidence in support of this theoretical mechanism. In addition, I explore specific channels that can potentially uphold high levels of prosocial behavior over time. I find that imperfect memory—the observer forgetting what they learned about the decision-maker in the past—helps to keep prosocial behavior at high levels. However, I also find that individuals are generally not forgiving; they believe that those who acted egoistically in the past will remain egoistic in the future. This lowers the supply of prosocial behavior over time.

Motivated investor narratives with Kai Barron  

(Abstract) We study whether motivated reasoning influences the narratives that individuals are willing to adopt. Specifically, we test whether individuals find narratives more plausible when they like, rather than dislike, the consequences implied by the narrative. In our experiment, an investor observes historical data from a particular company and decides whether or not to invest in the company. After taking this decision, the investor meets with a financial advisor who proposes an explanation of the company’s historical data to the investor. The investor may then update her beliefs about the company. Our preliminary results indicate that investors tend to reject narratives that contradict past choices they made—i.e., they reject narratives that suggest that their past investment choices were bad. We do not find any such effect if investors are instead exogenously endowed with an investment in the company. This implies that the act of choosing to invest or not is responsible for the motivated reasoning effect we observe.

Research Papers

Narrative persuasion with Kai Barron  [latest version]  [instructions]  [preregistration]  

(Abstract) We study how one person may shape the way another person interprets objective information. They do this by proposing a sense-making explanation (or narrative). Using a theory-driven experiment, we investigate the mechanics of such narrative persuasion. Our results reveal several insights. First, narratives are persuasive: We find that they systematically shift beliefs. Second, narrative fit (coherence with the facts) is a key determinant of persuasiveness. Third, this fit-heuristic is anticipated by narrative-senders, who systematically tailor their narratives to the facts. Fourth, the features of a competing narrative predictably influence both narrative construction and adoption.

Signaling motives in lying games revise and resubmit at Games and Economic Behavior,  [latest version]  

(Abstract) This paper studies the implications of agents signaling their moral type in a lying game. In the theoretical analysis, a signaling motive emerges where agents dislike being suspected of lying and where some lies are more stigmatized than others. The equilibrium prediction of the model can explain experimental data from previous studies, in particular on partial lying, where individuals lie to gain a non payoff-maximizing amount. I discuss the relationship with theoretical models of lying that conceptualize the image concern as an aversion to being suspected of lying and provide applications to narratives, learning, and the disclosure of lies.

Competition and moral behavior: A meta-analysis of 45 crowd-sourced experimental designs with Christoph Huber, Anna Dreber, Felix Holzmeister, and many more, Proceedings of the National Academy of Sciences, 2023, 120(23), 1-10  

(Abstract) Does competition affect moral behavior? This fundamental question has been debated among leading scholars for centuries, and more recently, it has been tested in experimental studies yielding a body of rather inconclusive empirical evidence. A potential source of ambivalent empirical results on the same hypothesis is design heterogeneity—variation in true effect sizes across various reasonable experimental research protocols. To provide further evidence on whether competition affects moral behavior and to examine whether the generalizability of a single experimental study is jeopardized by design heterogeneity, we invited independent research teams to contribute experimental designs to a crowd-sourced project. In a large-scale online data collection, 18,123 experimental participants were randomly allocated to 45 randomly selected experimental designs out of 95 submitted designs. We find a small adverse effect of competition on moral behavior in a meta-analysis of the pooled data. The crowd-sourced design of our study allows for a clean identification and estimation of the variation in effect sizes above and beyond what could be expected due to sampling variance. We find substantial design heterogeneity—estimated to be about 1.6 times as large as the average standard error of effect size estimates of the 45 research designs—indicating that the informativeness and generalizability of results based on a single experimental design are limited. Drawing strong conclusions about the underlying hypotheses in the presence of substantive design heterogeneity requires moving toward much larger data collections on various experimental designs testing the same hypothesis.

Observability and lying with Uri Gneezy, Agne Kajackaite, and Daniel Parra, Journal of Economic Behavior & Organization, 2021, 189, 132-149  

(Abstract) Experimental participants in a cheating game draw a random number and then report any number they wish, receiving a monetary payoff based only on the report. We study how these reports depend on the level of observability of both the random draw and the report by the experimenter. Our results show that whereas increasing the observability of the random draw decreases cheating, increasing the anonymity of the reports does not affect average reports.

Because I (don't) deserve it: Entitlement and lying behavior with Daniel Parra, Journal of Economic Behavior & Organization, 2021, 185, 495-512  [latest version]  

(Abstract) We study the effect of entitlement on the willingness to lie. We set up a model of lying where individuals feel more or less entitled to their endowment depending on how they earned it. When given the opportunity to lie to keep their endowment, individuals who feel more entitled are encouraged to lie while others are discouraged. To test the model predictions we use a laboratory experiment where we compare the lying behavior of participants endowed with a high endowment and participants endowed with a low endowment. In one treatment, the allocation of the endowment is decided by participants' performance, and in the other, it is determined by a random draw. Our study shows that deservingness influences lying in an intuitive direction: when participants' performance determines income, those who earn less money lie less than those who earn more. We do not find differences in lying when participants perform the same task but lie to keep windfall endowments.
Tilman Fries - tilman fries