Dear Colleagues,

I am currently conducting a meta-analytic review of research on ingroup favoritism. I request for you to share your published and unpublished studies on this topic. Specifically, I request studies that examine the difference in prosocial behavior with an in-group member, compared to an out-group member (or control group, such as a stranger). The measure of behavior can be a form of cooperation (e.g., behavior in a social dilemma), helping behavior, or other economic games (e.g., dictator game and trust game).

If you have studies to share, I will require statistical information on the mean differences in behavior between interacting with ingroup and outgroup members (e.g., the sample size and an independent t test or a pairwise t test, depending on the methods used) and some general information about the methods of the study. I am interested in collecting both unpublished and published studies.

You can contact me at the following email address: d.p.balliet@vu.nl

Thanks in advance for you help with this project.

Best Regards,

Daniel Balliet

Assistant Professor

VU University Amsterdam