关键词: 疼痛共情, 特质性自我构念, 内群体, 事件相关电位, N2, P3

Abstract:

Empathy to others' pain is key to human social interaction and development. Previous studies suggest that pain empathy is influenced by numerous factors, including different characteristics of the observed target and the observer. Moreover, the relationship between an observer and the target also plays an important role. Self-construal, a personality trait, reflects the extent to which people consider themselves as connected to or separated from others. Recently, researchers have found temporal self-construal priming could modulate empathic neural responses to pain and change racial in-group bias measured in the neural response to pain. Unlike temporary, situational self-construal, the dispositional self-construal is a stable trait, the formation of which is influenced by long-term cultural experience. Previous ERP studies have found dispositional self-construal to modulate self-relevant processing more rapidly than temporal self-construal. Thus, the present study explores whether dispositional self-construal is related to empathic neural responses to others' pain and whether in-group bias mediates such modulation. It has been shown that the temporal processing of empathy for pain consists of an early emotional sharing stage and a late cognitive evaluation stage. Accordingly, we assumed dispositional self-construal would correlate with either automatic emotional sharing or top-down controlled processes of empathy for pain.

In sum, the present study demonstrated a significant ingroup bias in the early N2 stage, but not in the late P3 stage. Moreover, dispositional self-construal correlated with both ingroup and outgroup empathy for pain, and high interdependence was associated with enhanced P3 response to other's pain regardless of group membership.

Twenty-seven Chinese participants took part in the present study. Before the formal experiment, participants were informed that the models in the pictures were selected from their fellow-townsman WeChat groups (ingroup) and other WeChat groups (outgroup). Next, we recorded electroencephalography (EEG) while participants took part in a word-priming paradigm, in which a word cue (“ingroup” or “outgroup”) was presented for 500 ms, indicating the identity of the model, followed by a picture of the model's face touched either by painful or non-painful stimulation. Participants were instructed to judge whether the model in the picture was feeling pain by pressing a button using the left or right index fingers. After the EEG recording, participants rated the intensity of pain supposedly felt by the model as well as the degree of unpleasantness they felt when they saw each picture. Participants also completed the 24-item SCS on a seven-point scale to evaluate their interdependence and independence of self-construal.

The ERP results showed a significant ingroup bias in the early N2 component. Painful stimuli elicited a greater negative shift relative to non-painful stimuli in response to ingroup faces. No such effect was observed on outgroup faces. The N2 component has previously been associated with automatic emotion sharing. A long latency empathic response was also observed at P3 over parietal electrodes. Painful stimuli elicited larger P3 amplitudes than the non-painful stimuli in both ingroup and outgroup face conditions. The P3 component is related to the cognitively controlled process of pain empathy. Importantly, correlation analysis revealed significant relationships between dispositional self-construal score (interdependence minus independence scores) and the amplitude difference (painful minus no-painful stimulus conditions) of P3 in both ingroup and outgroup face conditions. Furthermore, correlation coefficients were similar between ingroup and outgroup face conditions. In addition, we observed a positive relationship between the level of the interdependent self-construal and subjective rating of perceived pain and self-unpleasantness.

Key words: pain empathy, dispositional self-construal, ingroup, event-related potentials, N2, P3