Impact of Interactive Responses on Assertion Perception During Misinformation Evaluation: Behavioural and Neurocognitive Evidence

Assertion perception is a critical cognitive process for how people evaluate misinformation. Although prior work has examined various textual contexts, less is known about how different types of responses shape assertion perception. To address this gap, we investigated whether threatening responses are more likely to be accepted than non-threatening ones. Drawing on research on assertion criteria and common weakly justified comments on social platforms, we conducted three experiments to test this effect. Across studies, behavioural and EEG (N400) evidence consistently showed that threatening responses were associated with higher acceptance. This study provides two contributions: (1) it identifies how response type influences assertion perception, and (2) it demonstrates the usefulness of EEG as a physiological indicator for studying assertion processing. Our findings illuminate the cognitive-neural mechanisms of assertion processing, provide novel measurement paradigms, and underscore responses' pivotal role in propagating misinformation, offering anti-rumour intervention insights. Nonetheless, the study has several limitations-restricted ecological validity, a single cultural context, and limited generalisability. Future research should address these issues through more naturalistic designs, cross-cultural samples, computational modelling, and preregistered protocols.