Figure 3. ERP results. A, The grand-mean ERP waveforms for the four conditions. Waveforms were calculated by averaging the prefrontal data of F1, F2, Fz, FC1, FC2, and FCz electrodes. B, Topographies of N2 and P3. C, Amplitudes of N2 were calculated by averaging the data within a time window of 300 to 350 ms after the onset of the word-name combination. D, Amplitudes of P3 were calculated by averaging the data within a time window of 380 to 420 ms after the onset of the word-name combination. Forg-Fri, forgive friend condition; Comp-Fri, complain friend condition; Forg-Str, forgive stranger condition; Comp-Str, complain stranger condition. *p < .05.

Time-frequency results

Alpha oscillation. Repeated-measures ANOVA showed a significant two-way interaction between interpersonal distance ×attitude (F (1,36) = 5.33, p = .027,\(\eta_{P}^{2}\) = 0.129; Figure 4A). Simple effect analysis revealed that while participants had decreased alpha oscillation when reacting to forgive-than complain- label words in the friend condition (F (1,36) = 4.72, p = .036, \(\eta_{P}^{2}\) = 0.116; forgive- and complain- label words: 0.57 ± 0.10 and 0.75 ± 0.16), no such difference was observed in the stranger condition (F (1,36) = 0.01, p = .937, \(\eta_{P}^{2}\) = 0.000; forgive- and complain- label words: 0.63 ± 0.09 and 0.64 ± 0.12). No significant main effects of interpersonal distance(F (1,36) = 0.17, p = .683, \(\eta_{P}^{2}\) = 0.005) andattitude (F (1,36) = 2.10, p = .156,\(\eta_{P}^{2}\) = 0.055) were observed. Detailed statistics of simple effect analysis are listed in Table 2.
FAA results. Repeated-measures ANOVA showed a significant two-way interaction effect of interpersonal distance × attitude(F (1,36) = 4.27, p = .046, \(\eta_{P}^{2}\) = 0.106; Figure 4B). Simple effect analysis revealed that while participants exhibited lower FAA to forgive- than complain-label words in the friend condition (F (1,36) = 4.57, p = .037, \(\eta_{P}^{2}\) = 0.115; forgive- and complain- label words: -0.24 ± 0.11 and 0.02 ± 0.13), no such difference was observed in the stranger condition (F (1,36) = 0.59, p = .447, \(\eta_{P}^{2}\) = 0.016; forgive- and complain- label words: 0.04 ± 0.10 and -0.07 ± 0.13). No significant main effects of interpersonal distance(F (1,36) = 0.53, p = .473, \(\eta_{P}^{2}\) = 0.014) andattitude (F (1,36) = 0.72, p = .403,\(\eta_{P}^{2}\) = 0.020) were observed. Detailed statistics of simple effect analysis are listed in Table 2.