Extremism at the centre: Uncovering political diversity amongst midpoint responders on the left-right self-placement item

A significant body of research has examined the relationships between political ideology and conspiracy beliefs. Conspiracy theories are often considered the province of “extremist” political positions. Intriguingly, however, several recent studies have demonstrated that people at the midpoint of the left-right self-placement item often displayed elevated conspiracy beliefs. The cause of this “midpoint bump” is unknown. Based on these observations, our research investigated the extent to which midpoint bumps exist in other domains. Using data from the Australian Election Study (N = 2179) and the American National Election Study (N = 8280), we conducted polynomial tests on the relationships between the left-right item and a range of social and political attitudes. We found W-shaped relationships primarily across attitudes towards the political system and immigrants. To explore the possibility that subgroups may hold anti-establishment and anti-immigrant attitudes that distinguish them from typically-moderate responders, we conducted Latent Profile Analyses on midpoint responders. In both samples, one profile represented an extreme response pattern relative to other profiles, consistent with populist attitudes. We discuss the implications of the left-right scale conflating political diversity at the midpoint for ideological measurement, as well as how it hinders understanding anti-establishment tendencies across the political spectrum.