Approach or Avoidance? The Impact of Pain Expectation on Pain Empathy: An ERP Study.

Pain empathy plays an important role in both social bonding and defensive mechanisms, yet previous studies have mostly used non-predictive paradigms and rarely examined the effects of expectation. Using event-related potentials (ERPs), this study explored how pain expectation temporally modulates empathic responses and proposed an avoidance-approach dual-drive model. Behaviorally, participants responded faster and more accurately under pain-expectation conditions. At the neural level, greater N2 amplitudes were elicited by pain expectation, reflecting avoidance reactions driven by self-protection. In the P3 stage, two concurrent effects emerged: (1) overall P3 amplitudes decreased under pain expectation, suggesting reduced cognitive resource allocation due to avoidance; and (2) painful stimuli still evoked larger P3 amplitudes than neutral stimuli, indicating empathic engagement associated with approach motivation. These results suggest that pain empathy is not governed by a single mechanism but by a dynamic interplay between avoidance and approach motivations at different temporal stages, providing a neurophysiological framework that integrates defensive and affiliative needs in pain empathy.