Current Position
Global Network Professor of Economics, New York University in Abu Dhabi  

Editorial Positions
Main research interests
(i) evolution of cooperation, (ii) conflict resolution, (iii) determinants of anti-social and pro-social behavior, (iv) gender differences in competitiveness.  

Latest working papers
*NEW* "Predicting social tipping and norm change in controlled experiments(w. James Andreoni and Simon Siegenthaler) (2020) NBER Working Paper # 27310.

AbstractThe ability to predict when societies will replace one social norm for another can have significant implications for welfare, especially when norms are detrimental. A popular theory poses that the pressure to conform to social norms creates tipping thresholds which, once passed, propel societies toward an alternative state. Predicting when societies will reach a tipping threshold, however, has been a major challenge due to the lack of experimental data for evaluating competing models. We present evidence from a large-scale lab experiment designed to test the theoretical predictions of a threshold model for social tipping. In our setting, societal preferences change gradually, forcing individuals to weigh the benefit from deviating from the norm against the cost from not conforming to the behavior of others. We show that the model predicts accurately social tipping and norm change in 96% of experimental societies. Strikingly, when individuals determine the cost for non-conformity themselves, they set it too high, causing the persistence of detrimental norms. We also show that instigators of change tend to be more risk tolerant and to dislike conformity more. Our findings demonstrate the value of threshold models for understanding social tipping in a broad range of social settings and designing policies to promote welfare.

*NEW* "Does selection bias cause us to overestimate gender differences in competitiveness?" (w. Aurelie Dariel and Jan Stoop) (2020)  NYU Abu Dhabi WP #0046. 

AbstractExperimental evidence suggests there is a substantial difference in the willingness of men and women to compete that could help explain the gender gap in labor market outcomes. The use of volunteer samples, however, raises a question about whether self-selection into experiments biases the estimated difference in competitiveness. To address it, we first measure the willingness of 1,145 individuals to compete in a classroom experiment. We then identify among them the subset of ‘lab volunteers’ by observing who accepts an invitation to participate in lab experiments. To test for the existence of selection bias, we compare the gender gap among lab volunteers to that in the population from which they were recruited. We find that selection causes us to overestimate the gender gap in competitiveness by 16 percentage points in absolute terms and, in relative terms, by a factor of 2 to 3 depending on the econometric model. We also show that selection causes us to significantly overestimate the gender gap in risk attitudes and the tendency of low-performing men to select into competition. We present evidence men and women select differently into the lab, and discuss the implications of our findings for future research. 

*NEW* "Covenants before the swords: The limits to efficient cooperation in heterogeneous groups" (w. Christian Koch and Charles Noussair) (2020)  NYU Abu Dhabi WP #0048. 

AbstractWhen agents derive heterogeneous benefits from cooperation, a tension often arises between efficiency and equality that can impede their ability to cooperate efficiently. We design a lab experiment, in which we investigate the efficacy of communication and punishment, separately and jointly, to promote cooperation in such an environment. Our results reveal that communication allows most groups to establish covenants, i.e., agreements about the profile of individual contributions, while the threat of punishment (the ‘sword’) discourages deviations from the covenants. Most covenants, however, reflect a concern for equality. As a result, cooperation levels and earnings fall substantially below the maximum possible. The timing of communication is also critical: covenants reduce the use of sanctions dramatically when communication precedes punishment opportunities but when punishment precedes communication opportunities, a history of sanctioning emerges which reduces the probability that groups establish covenants subsequently. Our findings illustrate not only the benefits of early communication, but also some limits to self-governance in heterogeneous groups. 

"The ghost of institutions past: history as an obstacle to fighting tax evasion" (w. Aaron Kamm and Christian Koch) (2017) NYU Abu Dhabi WP #008. Revise and resubmit at the European Economic Review.

AbstractIf taxpayers believe past rates of compliance are indicative of the future, traditional measures for 
combating tax evasion can be compromised. We present evidence from a 
novel laboratory experiment with strategic complementarities showing that a history 
of low compliance can render a major institutional reform ineffective at reducing 
tax evasion. The experimental treatments manipulate the history of tax compliance 
by varying the percentage of tax revenue embezzled by a ‘politician’ – our measure 
of ‘institutional quality’. We show that tax compliance is substantially higher in 
good-quality than bad-quality institutions when there is no history of tax evasion. 
When a bad-quality institution is replaced with a good-quality one, however, tax 
compliance remains low, as if the institutional change had not occurred. The reason 
is that the institutional change leaves expectations about future compliance largely 
unaffected. A history of high-quality institutions, on the other hand, shields tax 
compliance only partly from institutional deterioration. We discuss reasons for this, 
policy implications of our findings, and evidence that a society-wide poll can assist 
in overcoming the ‘ghost of institutions past’.

"Are the rich more selfish than the poor? A field-experimental test of a common stereotype(w. James Andreoni and Jan Stoop) revise and resubmit Nature Communications  
(The latest version is available upon request. The NBER WP can be downloaded here.) 
[You can read more about this study at The Conversationhear about it at Freakonomics Radio, and even watch a short video about it.]

AbstractThe growing concentration of resources among the rich has re-ignited a discussion about whether the rich are more selfish than others. Despite a common stereotype portraying them as excessively selfish, the current balance of evidence from incentivized experiments and surveys seems to contradict this view. Methodological issues, however, prevent us from ruling out alternative interpretations of the evince. Here, we present the first results from a field experiment exploring the relative pro-sociality of the rich. By exploring the willingness of unaware, randomly selected, rich and poor individuals to undertake a costly pro-social act, our experiment overcomes the interpretation problems found in previous studies. We show that the rich behave less selfishly across all conditions. Despite controlling for a number of covariates and performing a series of ancillary tests, we fail to find any evidence supporting the stereotypical view of the selfish rich. We discuss implications for future research and policy. 

Office hours 
Tuesday and Thursday, 9-10 am
For meetings outside these hours, please send me an email.

Office location
NYU Abu Dhabi, Saadiyat Island, Building A5, Office 1143

This website was (partly) updated on: June 9, 2020