Asymmetry in political polarization at multiple levels of bias

While some studies show ideological asymmetry in outgroup bias between rightists and leftists, those studies often target an ideologically biased outgroup. Here, we bypass this issue by targeting the ideological outgroups (rightists for leftists, and leftists for rightists). We rely on a magnetoencephalography-based approach delineating function-specific neural mechanisms to test for ideological asymmetries at multiple levels: explicit psychological self-reports, implicit behavioral bias, and neural oscillations. Using a computational model balancing the stimuli and screening 81 rightists and leftist Israeli individuals, we find ideological asymmetry with rightists being more biased at all three levels. Furthermore, the neural results add important insights by uncovering two underlying mechanisms: The first (late beta-band motor activity) is strongly associated with implicit behavior, while the second (early alpha-band dorsal anterior cingulate activity) reveal an antileftist bias for both groups. We discuss implications of the findings on bias, ideological asymmetry, their neural underpinnings, and social norms.