Contextual Predictability Modulates Neural Processing of Social Threat Words in High and Low Social Anxiety: Evidence from ERPs and Theta Oscillations.

Background: Individuals with high social anxiety (HSA) consistently exhibit attentional biases toward social threat. However, most evidence derives from paradigms in which threat and neutral stimuli are unpredictably intermixed, leaving it unclear whether such biases reflect heightened sensitivity to threat content per se or increased sensitivity to contextual unpredictability, where emotional valence changes unpredictably across trials. Methods: HSA and low social anxiety (LSA) individuals completed an emotional Stroop task comprising a mixed context, in which threat and neutral words were randomly presented, and a threat-only context, in which threat was fully predictable Behavioral responses, event-related potentials (P2, EPN, LPP), and theta-band oscillations were analyzed. Results: Behaviorally, HSA participants responded more slowly than LSA participants in the mixed context but faster in the threat-only context. At the neural level, early perceptual processing indexed by P2 did not differ reliably across groups. In contrast, EPN amplitudes were selectively enhanced in HSA individuals under predictable threat, whereas LSA individuals showed increased LPP amplitudes reflecting sustained evaluative engagement. Frontal theta power was greater in LSA than HSA individuals in the mixed context. Conclusion: These findings suggest that threat-related bias in HSA participants is associated with contextual predictability, in addition to threat exposure. HSA is characterized by intact or heightened early sensitivity to threat alongside context-dependent differences in later evaluative and regulatory processes. By highlighting the role of contextual predictability and temporal dynamics, the present study provides a more nuanced understanding of emotional dysregulation in high social anxiety.