Are There Ideological Asymmetries in Intergroup Bias? A Minimal Groups Approach

The divide between political liberals and conservatives is rapidly growing. Several influential theories contend that this divide hinges on orientations towards social groups, such that conservatives (versus liberals) show a greater tendency to favor their “ingroups” and discriminate against “outgroups”. However, other theories contend that liberals and conservatives do not differ in their degree of intergroup bias. Both perspectives have received empirical support, and the debate has reached a standstill. We argue that this theoretical and empirical stalemate stems from inherent limitations of examining attitudes towards real-world social groups—a strategy used by both sides of the debate. Drawing on social identity theory, we conducted a series of four studies (Total N = 4389) using “minimal groups” (i.e., experimentally constructed groups) to determine whether and why ideological differences in intergroup bias may exist. We found robust evidence of ideological differences in intergroup bias, with conservatives favoring their own social groups over others. These ideological differences were relatively small but statistically robust across most contexts we examined. Importantly, however, when groups were based on shared moral and political values, liberals showed as much intergroup bias as conservatives. These results help resolve this long-standing debate and deepen our understanding of the psychological underpinnings of political ideology.