The Out‐Group Homogeneity Effect Across Development: A Cross‐Cultural Investigation

The present studies investigated the out‐group homogeneity effect in 5‐ and 8‐year‐old Israeli and German children ( n  =   150) and adults ( n  =   96). Participants were asked to infer whether a given property (either biological or psychological) was true of an entire group—either the participants' in‐group (“Jews” or “Germans”) or their out‐group (“Arabs” or “Turks”). To that end, participants had to select either a homogenous or a heterogeneous sample of group members. It was found that across ages and countries, participants selected heterogeneous samples less often when inferring the biological properties of out‐compared to in‐group members. No effect was found regarding psychological properties. These findings have important implications for our understanding of the origins of intergroup bias.