Research

"Social Preferences and the Variability of Conditional Cooperation" (with Simon Gächter, Kyeongtae Lee & Martin Sefton)
Revise and Resubmit at Economic Theory

We experimentally examine how the incentive to defect in a social dilemma affects conditional cooperation. In our first study we conduct online experiments in which subjects play eight Sequential Prisoner’s Dilemma games with payoffs systematically varied across games. We find that few second movers are conditionally cooperative (i.e., cooperate if and only if the first mover cooperates) in all eight games. Instead, most second-movers change strategies between games. The rate of conditional cooperation is higher when the own gain from defecting is lower and when the loss imposed on the first mover from defecting is higher. This pattern is consistent with both social preference models and stochastic choice models. To explore which model explains our findings we employ a second study to jointly estimate noise and social preference parameters at the individual level. The majority of our subjects place significantly positive weight on others’ payoffs, supporting the underlying role of social preferences in conditional cooperation.

"‘IOS11’: A new, extended, interactive version of the ‘Inclusion of Other in the Self’ scale" (with Chris Starmer, Fabio Tufano & Simon Gächter)

We introduce and test a new tool designed to measure “relationship closeness”. Studying relationship closeness has a long history in psychology and is currently expanding in other fields including economics. Our new measurement tool is a refinement of the widely used ‘Inclusion of Other in the Self’ scale (IOS for short) of Aron et al. (1992) and is designed to embody three key features. First, it retains attractive attributes of the standard IOS tool including being an effective measurement technique which is easy to implement and understand. Second, we enhance the scope for convenient use of the tool via the development of a portable interactive interface that will be particularly useful in online studies. Thirdly and crucially, through extensive pre-registered experimental testing, we demonstrate that our enhanced tool – IOS11 which features an 11-point response scale – outperforms previous versions of IOS in better proxying features of relationships captured by a range of more complex survey tools; the performance of IOS11 is also indistinguishable from that of the more complex ‘Oneness’ measure of Cialdini et al. (1997) which uses the standard IOS as one of its two-item inputs.