The Temporal Sequence of Party Leader Incongruence: a data-driven ERP study

Partisanship is a powerful social identity that not only conditions how citizens vote, but also how they reason. The ’Hot Cognition’ hypothesis posits that affective associations are activated immediately upon exposure to political stimuli, such as party leaders delivering polarizing messages. The integration of the speaker with the message might be comprised of temporally distinct processes: automatic affective response triggered by the identity of the source (disliked leader), and a more conscious, evaluative response triggered by leader misalignment. Yet, previous work has relied on methods that cannot temporally disentangle neural responses to party leaders. We conducted a preregistered EEG study (N = 44) using a task with just politicians’ faces and a task with faces and statements. Out-party faces elicited an enhanced early posterior positivity (200–356 ms). When paired with messages, this early response (148–424 ms) was amplified by out-party faces and counter-attitudinal statements, and aligned with slower reaction times. Consistent with a visual P2 component, these findings suggest that partisanship prioritizes the detection of political opponents within 150 milliseconds, well before conscious evaluation begins.