Aljaž Ule

Faculty of Economics and Econometrics of the
University of Amsterdam

Phone: +31 20 525 4205


Background and interests

Aljaž is assistant professor at the Department of General Economics, teaching courses on microeconomics, experimental economics and game theory. His research is focused mainly on dynamics of social institutions such as social networks, culture and social norms, and their effect on social behavior such as voluntary assistance and cooperation. His research tools include laboratory experiments, computer simulations and game theoretic analysis.



Schram, Arthur and Aljaz Ule (2013) Democracy and Regulation: The Effects of Electoral Competition on Infrastructure Investments PDF-file
This paper investigates infrastructure investment in markets where regulation is subject to varying degrees of manipulation by elected politicians. Based on a model of price regulation in a market with increasing demand and long-term returns on investment we construct a multi-period game between a service provider, consumers with voting rights and elected decision makers. In each period the consumers elect a decision maker who may then regulate the price for service provision. Before an election the service provider chooses whether to increase its capacity. Investment is irreversible and profitable only with a sufficiently high price. We derive the subgame perfect equilibrium for this game and investigate the price and investment dynamics through an experiment with human subjects. The experimental results show that service providers invest when decision-makers’ interests align with their own, though prices may rise inefficiently high when the regulatory framework is made independent of future political manipulation. Independency of regulation thus decreases efficiency and consumer surplus. In contrast, when decision-makers’ interests do not align with service providers’ we find efficiency only when regulation can be made independent from electoral dynamics.


Schram, Arthur and Alja˛ Ule (2019) Handbook of Research Methods and Applications in Experimental Economics PDF-file Link to book
Dedicated to the discussion of methods, the handbook offers a reference to the current state-of-the-art and standards in experimental economics. Its 21 chapters comprehensively cover issues such as deception, replication, recruitment, randomization, data analysis, laboratory organization, and experimenter demand. Further topics include incentives, preferences, macro experiments, policy design, cross cultural experiments, real effort tasks, and communication. Several chapters are devoted to methods in personality psychology, neuroeconomics, or field experiments. Two chapters introduce new theoretic developments on risky choice, and a non-parametric generalization of QRE.


Bardsley, Nicholas and Aljaz Ule (2017) Focal Points Revisited: Team Reasoning, the Principle of Insufficient Reason and Cognitive Hierarchy Theory Journal of Economic Behavior & Organization 133, 74-86 PDF-file Link to article
Coordination on focal points in one shot games can often be explained by team reasoning, a departure from individualistic choice theory. However, a less exotic explanation of coordination is also available based on best-responding to uniform randomisation. We test the team reasoning explanation experimentally against this alternative, using coordination games with variable losses in the off-diagonal cells. Subjects’ responses are observed when the behaviour of their partner is determined in accordance with each theory, and under game conditions where behaviour is unconstrained. The results are more consistent with the team reasoning explanation. Increasing the difficulty of the coordination tasks produces some behaviour suggestive of response to randomisation, but this effect is not pronounced.


Swakman, Violet, Lucas Molleman, Alja˛ Ule and Martijn Egas (2016) Reputation-based cooperation: empirical evidence for behavioral strategies Evolution and Human Behavior 37, 230-235 Link to article
Human cooperation in large groups can emerge when help is channeled towards individuals with a good reputation of helping others. Evolutionary models suggest that, for reputation-based cooperation to be stable, the recipient’s reputation should not be based only on his past behavior (1st-order information) but also on the past behavior of the recipient's recipient (2nd-order information). Second-order information reflects the context of others' actions, and allows people to distinguish whether or not giving (or denying) help was justified. Little is known yet about how people actually condition their cooperation on 2nd-order information. With a behavioral experiment, we show that people actively seek 2nd -order information and take this into account in their own helping decisions. In an anonymous iterated helping game, donors learned if their recipients helped others in the past and could obtain 2nd-order information about these actions. Donors often requested this 2nd-order information and were especially interested to know why help was denied (i.e., defection). Justified defection was rewarded: help was generally directed towards those who defected against the selfish, and away from those who defected against helpful individuals. A detailed analysis of individual strategies reveals that many subjects based their decisions solely on 1st-order information about their recipients' past behavior. However, a substantial fraction of subjects consistently considered also the 2nd-order information about their recipients' behavior. Our results provide strong empirical support for the mechanisms that theoretically underpin reputation-based cooperation, and highlight pronounced individual variation in human cooperative strategies.


Ule, Aljaz, Arthur Schram, Arno Riedl, and Tim Cason (2009) Indirect Punishment and Generosity Toward Strangers Science 326, 1701-1703 supporting online material Link to article
Many people incur costs to reward strangers who have been kind to others. Theoretical and experimental evidence suggests that such “indirect rewarding” sustains cooperation between unrelated humans. Its emergence is surprising, because rewarders incur costs but receive no immediate benefits. It can prevail in the long run only if rewarders earn higher payoffs than “defectors” who ignore strangers’ kindness. We provide experimental evidence regarding the payoffs received by individuals who employ these and other strategies, such as “indirect punishment” by imposing costs on unkind strangers. We find that if unkind strangers cannot be punished, defection earns most. If they can be punished, however, then indirect rewarding earns most. Indirect punishment plays this important role, even if it gives a low payoff and is rarely implemented.
Goeree, Jacob K., Arno Riedl and Aljaz Ule (2009) In search of stars: Network formation among heterogeneous agents Games and Economic Behavior 67, 445-466 Link to article
This paper reports results from a laboratory experiment on network formation among heterogeneous agents. The experimental design extends the Bala–Goyal [Bala, V., Goyal, S., 2000. A non-cooperative model of network formation, Econometrica 68, 1131–1230] model of network formation with decay and two-way flow of benefits by introducing agents with lower linking costs or higher benefits to others. Furthermore, agents' types may be common knowledge or private information. In all treatments, the (efficient) equilibrium network has a “star” structure. While equilibrium predictions fail completely with homogeneous agents, star networks frequently occur with heterogeneous agents. Stars are not born but rather develop: with a high-value agent, the network's centrality, stability, and efficiency all increase over time. A structural econometric model based on best response dynamics and other-regarding preferences is used to analyze individual linking behavior. Maximum-likelihood estimates of the underlying structural parameters, obtained by pooling data from several treatments, allow us to explain the main treatment effects.


Ule, Aljaz (2008) Partner Choice and Cooperation in Networks: Theory and Experimental Evidence Springer Verlag Link to article


Ule, A. and Boucherie, R.J. (2006) Adaptive dynamic capacity borrowing in road-covering mobile networks. Resource allocation in next generation wireless networks. Wireless Networks and Mobile Computing 5. Pages 67-87. Nova Science Publishers, New York
This paper introduces adaptive dynamic capacity borrowing strategies for wireless networks covering a road. In a F/TDMA-based model, road traffic prediction models are used to characterise the movement of hot spots, such as traffic jams, and subsequently to predict the teletraffic load offered to the wireless network. A dynamic upper bound on the capacity required to achieve a specified Quality of Service level in the cells is computed. Restricting borrowing to neighbouring cells to avoid excessive re-allocation of capacity, optimal capacity borrowing strategies based on traffic movement and traffic density are given. These strategies can be characterised by a straightforward rule of thumb: borrow capacity from the cell on the steeper side of the traffic peak, that makes our strategy easily implementable. Results of a dynamic simulation under realistic load indicate a significant reduction of call blocking probabilities under our optimal capacity borrowing strategy. A possible extension to CDMA-based systems is briefly indicated.


Ule, Jernej, Aljaz Ule, Joanna Spencer, Alan Williams, Jing-Shan Hu, Melissa Cline, Hui Wang, Tyson Clark, Claire Fraser, Matteo Ruggiu, Barry R Zeeberg, David Kane, John N Weinstein, John Blume and Robert B Darnell (2005) Nova regulates brain-specific splicing to shape the synapse Link to article
Alternative RNA splicing greatly increases proteome diversity and may thereby contribute to tissue-specific functions. We carried out genome-wide quantitative analysis of alternative splicing using a custom Affymetrix microarray to assess the role of the neuronal splicing factor Nova in the brain. We used a stringent algorithm to identify 591 exons that were differentially spliced in the brain relative to immune tissues, and 6.6% of these showed major splicing defects in the neocortex of Nova2-/- mice. We tested 49 exons with the largest predicted Nova-dependent splicing changes and validated all 49 by RT-PCR. We analyzed the encoded proteins and found that all those with defined brain functions acted in the synapse (34 of 40, including neurotransmitter receptors, cation channels, adhesion and scaffold proteins) or in axon guidance (8 of 40). Moreover, of the 35 proteins with known interaction partners, 74% (26) interact with each other. Validating a large set of Nova RNA targets has led us to identify a multi-tiered network in which Nova regulates the exon content of RNAs encoding proteins that interact in the synapse.


Ule, Aljaz and Richard J. Boucherie (2003) On the Distribution of Calls in a Wireless Network driven by Fluid Traffic. European Journal of Operational Research 147, 146-155 Link to article
Ule, Jernej, Kirk B. Jensen, Matteo Ruggiu, Aldo Mele, Aljaz Ule and Robert B. Darnell (2003) CLIP Indentifies Nova-Regulated RNA Networks in the Brain SCIENCE 302, 1212-1215