Groupy and Not Groupy Behavior: Deconstructing Bias in Social Preferences

This paper finds systematically different individual behavior in group settings. Each participant allocates income in two treatments, a minimal group setting and a political group setting. A large set of subjects show ingroup bias in both, indicating that bias depends on group division per se rather than group identity. Other subjects show no bias in either setting. While the average subject is more inequity averse towards ingroup than towards outgroup (replicating previous studies), the average is not representative. Thirty-four percent of subjects have the same social preferences for outgroup and ingroup. On the other hand, twenty percent of subjects destroy income when facing an outgroup participant—sacrificing own income to lower outgroup incomes. The results indicate some people are “groupy” and respond to group divisions, while others are “not groupy” with the same social preferences throughout the experiment. Out-oflaboratory behavior support these categorizations; “not groupy” subjects are less likely to affiliate themselves with a political party, all else equal. * Contacts: [email protected], [email protected], [email protected], [email protected]. Authors are listed in alphabetical order following the convention in economics, except for the lab director who is listed last following the convention in psychology & neuroscience. We are grateful to George Akerlof, Jeff Butler, John Miller, Pedro Rey-Biel and seminar and conference participants at Berkeley, Canadian Institute for Advanced Research, Conference on the Economics of Interactions & Culture (EIEF), Duke, Ecole Polytechnique, Erasmus Choice Symposium, Pompeu Fabra, Institute for Economic Analysis & Universitat Autònama de Barcelona, Maryland, Paris School of Economics, Sciences Po, Stanford, THEEM, Université Aix-Marseilles, and Washington University for their comments. We thank Catherine Moon, Robert Richards, Sierra Smucker for research assistance. We thank the Social Science Research Institute at Duke for sponsoring our faculty fellows program in 20102011, “From Brain to Society (and Back),” and we are grateful for funding from the Transdisciplinary Prevention Research Center (TPRC) at Duke, as supported by the National Institute on Drug Abuse grant DA023026.