Repeated interactions provide a prominent but paradoxical hypothesis for human cooperation in one-shot interactions. Intergroup competitions provide a different hypothesis that is intuitively appealing but heterodox. We show that neither mechanism reliably supports the evolution of cooperation...

An apology is a strong and cheap device to restore social or economic relationships that have been disturbed. In a laboratory experiment we find that harmdoers use apologies in particular if they fear punishment and when their intentions cannot be easily inferred. After offenses with ambiguous...

We investigate whether risk, time, environmental, and social preferences affect single family homeowners' investments in energy efficient renovations and energy quality of their house using established experimental measures and questionnaires. We find that homeowners who report to be more risk...