Explaining the evolution and maintenance of cooperation among unrelated individuals is one of the fundamental problems in biology and the social sciences. Recent experimental evidence suggests that altruistic punishment is an important mechanism to maintain cooperation among humans. In this...

See also <I>Social ties and coordination on negative reciprocity: The role of affect</I>, <A href="http://www.sciencedirect.com/science/article/pii/S0047272707000679">Journal of Public Economics'</A>, 2008, 92, 34-53.<P> This experimental study investigates how behavior changes after punishment for an unkind action. It also studies how fairness perceptions affect the reaction to...</p></a></i>

We investigate experimentally whether emotions affect bidding behavior in a firstprice auction. To induce emotions, we confront subjects after a first auction series with apositive or negative random economic shock. We then explore the relation between emotions andbidding behavior in a second...

This discussion paper resulted in an article in the 'Journal of Economic Behavior & Organization' (2014). Volume 108, pages 224-235.<P> In criminal cases judges evaluate and combine probabilistic evidence to reach verdicts. Unavoidably, errors are made, resulting in unwarranted conviction or...</p>