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Cited by 58Neuroendocrine regulation and behaviorSocial and Intergroup PsychologyEmotions and Moral Behavior

A neurobiological association of revenge propensity during intergroup conflict

Open access
Han, Xiaochun, Gelfand, Michele J, Wu, Bing, Zhang, Ting, Li, Wenxin, Gao, Tianyu, Pang, Chenyu, Wu, Taoyu +4 more·2020·eLife
DOI 10.7554/elife.52014PMC PMC7058385
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Abstract

Revenge during intergroup conflict is a human universal, but its neurobiological underpinnings remain unclear. We address this by integrating functional MRI and measurements of endogenous oxytocin in participants who view an ingroup and an outgroup member's suffering that is caused mutually (Revenge group) or by a computer (Control group). We show that intergroup conflict encountered by the Revenge group is associated with an increased level of oxytocin in saliva compared to that in the Control group. Furthermore, the medial prefrontal activity in response to ingroup pain in the Revenge group but not in the Control group mediates the association between endogenous oxytocin and the propensity to give painful electric shocks to outgroup members, regardless of whether they were directly involved in the conflict. Our findings highlight an important neurobiological correlate of revenge propensity, which may be implicated in conflict contagion across individuals in the context of intergroup conflict.

AI snapshot

Written from the paper’s full text.

TL;DR

In a between-subjects fMRI and salivary-oxytocin study, participants who witnessed an ingroup member harmed by an outgroup member showed higher endogenous oxytocin than controls and stronger medial prefrontal responses to ingroup pain. In the revenge group only, mPFC activity to ingroup pain mediated the link between endogenous oxytocin and self-reported propensity to punish outgroup members, including uninvolved outgroup members.

Key findings

  • Salivary oxytocin was higher in the Revenge group than the Control group at all three time points: Time-1 60.40 ± 49.25 vs. 24.68 ± 32.46 pg/ml; Time-2 106.19 ± 61.52 vs. 47.42 ± 40.83 pg/ml; Time-3 60.96 ± 51.92 vs. 21.72 ± 24.87 pg/ml; Group effect F(1,67) = 22.66, p < 0.001, η²p = 0.253; Group × Time F(2,134) = 4.04, p = 0.020, η²p = 0.057.
  • In the Revenge but not Control group, endogenous oxytocin at Time-1 predicted mPFC activity in response to Involved_Ingroup pain; moderation interaction ΔR² = 0.05, ΔF(1,65) = 5.70, p = 0.03. The OT–mPFC coupling was stronger for Involved_Ingroup than Uninvolved_Ingroup targets: R² = 0.15, F(1,75) = 12.99, p < 0.001.
  • In the Revenge group only, mPFC activity to Involved_Ingroup pain positively predicted punishment tendencies toward Involved_Outgroup and Uninvolved_Outgroup targets: r = 0.35 and 0.42; p = 0.026 and 0.014, FDR corrected.
  • mPFC activity mediated the association between Time-1 oxytocin and punishment tendencies toward Involved_Outgroup targets (indirect effect = 0.19, 95% CI 0.01–0.44) and Uninvolved_Outgroup targets (indirect effect = 0.25, 95% CI 0.08–0.46). A separate behavioral experiment found self-reported punishment tendencies correlated with actual punishment decisions toward Involved_Outgroup targets in both groups (r = 0.75 and 0.70, FDR-corrected ps < 0.001).

Methods

  • Between-subjects fMRI design: 44 male Chinese university students recruited per group; 4 per group excluded for excessive head movement, leaving 40 per group for fMRI analyses. The Revenge group viewed ingroup and outgroup confederates giving each other painful/non-painful shocks; the Control group viewed confederates receiving shocks from a computer. Saliva was collected at three time points (after initial conflict, after scanning, and 15 min later).
  • Participants viewed painful vs. neutral expressions of involved and uninvolved ingroup/outgroup targets during fMRI and later reported punishment tendencies. An independent behavioral experiment used 40 Revenge and 39 Control male Chinese university students.
  • Analyses included whole-brain GLMs (voxel-level p < 0.001, cluster-level p < 0.05 FWE corrected), leave-one-out ROI analyses, moderation analyses, and mediation analyses with bootstrapping (5000 resamples). Oxytocin was assayed from saliva using a commercial OT-ELISA kit.

Limitations

  • Stated: punishment tendencies were estimated by self-report, and the paper notes it was unclear whether these measures correlated with revengeful behavior; the authors addressed this with an independent behavioral experiment showing correlations with actual punishment decisions. The authors also state the paradigm should be applied to other samples (e.g., females) and cultures, and that other revenge motivations (e.g., threat to group pride, empathy for harmed ingroup members, normative pressure) were not examined.
  • Evident from the text: the fMRI and mediation findings are correlational and cannot establish causal direction; the samples were all male Chinese university students, limiting generalizability.
  • Evident from the text: oxytocin measurement failed for some participants, leaving 37 Revenge and 40 Control participants for OT-related analyses.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.7554/elife.52014

Cites

Statistics

32 tests recomputed · 0 with the reported and recomputed p on opposite sides of .05

Claims the paper makes

0 of 65 cited sources checked · 0 supported · 0 flagged

  • Findingown data

    In the Revenge group, intergroup conflict is associated with an increased level of oxytocin in saliva compared to the Control group.

    “We show that intergroup conflict encountered by the Revenge group is associated with an increased level of oxytocin in saliva compared to that in the Control group.”
    • Also stated in: § Increased endogenous OT in Revenge groups when compared to Control groups · plain
      “The results showed a significant effect of Group (F(1,67) = 22.66, p<0.001, η2p = 0.253) and a significant interaction of Group × Timing (F(2,134) = 4.04, p=0.020, η2p = 0.057; Figure 3A; see Table 1 for results of simple effect analyses).”
    Quote in the paperSubstantial claim
  • Findingown data

    Participants in both conditions reported greater schadenfreude when viewing outgroup vs. ingroup targets' pain.

    “By contrast, the participants in both conditions reported greater schadenfreude when viewing outgroup vs. ingroup targets’ pain (2.22 ± 1.60 vs. 1.61 ± 1.00; F(1,78) = 14.91, p<0.002, FDR corrected, η2p = 0.160).”
    Quote in the paperSubstantial claim
  • Findingown data

    Participants in both conditions reported greater tendencies to punish outgroup targets.

    “Finally, participants in both conditions reported greater tendencies to punish outgroup targets (3.23 ± 1.91 vs. 2.26 ± 1.53; F(1,78) = 27.19, p<0.002, FDR corrected, η2p = 0.259, Figure 2A).”
    Quote in the paperSubstantial claim
  • Findingown data

    Participants in both conditions reported greater trust and likability for ingroup than outgroup members.

    “Moreover, the participants in both conditions reported greater trust (5.53 ± 1.38 vs. 4.51 ± 1.49; F(1,78) = 28.62, p<0.002, FDR corrected, η2p = 0.268) and likability (ingroup: 5.32 ± 1.53; outgroup: 4.51 ± 1.47; F(1,78) = 23.57, p<0.002, FDR corrected, η2p = 0.232) for ingroup than outgroup members.”
    Quote in the paperSubstantial claim
  • Findingown data

    In the Revenge group but not the Control group, medial prefrontal activity in response to ingroup pain mediates the association between endogenous oxytocin and the propensity to give painful electric shocks to outgroup members.

    “Furthermore, the medial prefrontal activity in response to ingroup pain in the Revenge group but not in the Control group mediates the association between endogenous oxytocin and the propensity to give painful electric shocks to outgroup members, regardless of whether they were directly involved in the conflict.”
    Quote in the paperSubstantial claim
  • May combine two claims. 19
  • Classified as probably not a substantial claim. 51
  • The quote only partly states this claim. 1

  • May combine two claims.

    Findingown data

    Participants reported a greater number of painful shocks received by ingroup than by outgroup members, even though Involved_Ingroup and Involved_Outgroup targets actually received the same numbers of painful shocks.

    “Participants reported a greater number of painful shocks received by ingroup than by outgroup members, even though Involved_Ingroup and Involved_Outgroup targets actually received the same numbers of painful shocks.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S1 (asserted), S3 (load-bearing), S4 (based).

    Findingown data

    When viewing ingroup vs. outgroup targets' pain, participants in both conditions reported greater fear.

    “and fear (2.64 ± 1.97 vs. 2.36 ± 1.72; F(1,78) = 3.95, p=0.050, η2p = 0.048, all FDR corrected).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Separate whole-brain analyses that collapsed all participants in the Revenge and Control groups identified activations in the mPFC, aMCC, bilateral AI/IFG, and left TPJ in response to ingroup targets' pain but only in the mPFC in response to outgroup targets' pain.

    “Separate whole-brain analyses that collapsed all participants in the Revenge and Control groups identified activations in the mPFC, aMCC, bilateral AI/IFG, and left TPJ in response to ingroup targets' pain but only in the mPFC in response to outgroup targets' pain (combined a voxel level threshold p<0.001 and a cluster level threshold p<0.05, FWE corrected, Figure 4B, Supplementary file 4).”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    The mean Euclidean distance between the two bootstrapped samples is 32.29, with a 95% confidence interval of 11.55-54.61.

    “The mean distance between the two samples is 32.29, with a 95% confidence interval of 11.55–54.61.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Endogenous OT increased more after further witnessing intergroup conflict at Time-2 and dropped when intergroup conflict had ended at Time-3.

    “In addition, the endogenous OT increased more after further witnessing intergroup conflict (e.g., at Time-2) and dropped when intergroup conflict had ended (e.g., at Time-3).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The Revenge group showed a greater increase in OT level from Time-1 to Time-2 and a greater decrease of OT level from Time-2 to Time-3 compared to the Control group.

    “Specifically, we conducted a bootstrapping analysis to illustrate a greater increase in OT level from Time-1 to Time-2 and a greater decrease of OT level from Time-2 to Time-3 in the Revenge compared to Control group.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Neither the Revenge group nor the Control group showed activations in the reward system when viewing outgroup members' suffering.

    “Although previous research has shown that viewing outgroup pain can activate the nucleus accumbens (NAcc) and greater NAcc activity predicted less motivation to help outgroup members (Hein et al., 2010; Luo et al., 2015), neither the Revenge group nor the Control group in our work showed activations in the reward system when viewing outgroup members' suffering.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites Hein et al., 2010 source

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    • cites Luo et al., 2015 source

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    Premisecitation

    Revenge is a global phenomenon and a causal factor in many homicides and transgenerational conflicts.

    “Revenge, which refers to taking actions of harming someone in retaliation for an injury (Elshout et al., 2015; Jackson et al., 2019), is a global phenomenon and a causal factor in many homicides and transgenerational conflicts (Kopsaj, 2016; Jackson et al., 2019).”
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    Premisecitation

    Punishment decisions to prevent social norm violations have been associated with increased activities in both the empathy and theory-of-mind networks, including the aMCC, AI, and mPFC.

    “Punishment decisions to prevent social norm violations have been associated with increased activities in both the empathy and theory-of-mind networks, including the aMCC, AI, and mPFC (Krueger and Hoffman, 2016).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Krueger and Hoffman, 2016

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    Premisecitation

    mPFC/aMCC activities are modulated by administered OT.

    “and mPFC/aMCC activities are modulated by administered OT (Sabihi et al., 2014; Eckstein et al., 2015; Liu et al., 2017; Wang et al., 2017).”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Sabihi et al., 2014 source

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    • cites Eckstein et al., 2015 source

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    • cites Liu et al., 2017 source

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    Premisecitation

    Recent behavioral research using economic games suggests that ingroup love plays a key role in driving economic punishment towards the outgroup.

    “Recent behavioral research using economic games suggests that ingroup love plays a key role in driving economic punishment towards the outgroup (Halevy et al., 2008; De Dreu, 2010; De Dreu et al., 2010; Halevy et al., 2012).”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites Halevy et al., 2008 source

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    Premisecitation

    OT administration promotes motivation to sacrifice outgroup targets and facilitates within-group coordination for successful outgroup attack during economic games.

    “OT administration also promotes motivation to sacrifice outgroup targets (De Dreu et al., 2011) and facilitates within-group coordination for successful outgroup attack during economic games (Zhang et al., 2019).”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites De Dreu et al., 2011 source

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    • cites Zhang et al., 2019 source

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    Premisenone given

    Despite the severe social consequences of revenge, its neurobiological underpinnings remain unclear.

    “Nevertheless, despite the severe social consequences of revenge, its neurobiological underpinnings remain unclear.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    mPFC activity in response to perceived pain is associated with decisions to help ingroup members.

    “In addition, the mPFC activity in response to perceived pain is associated with decisions to help ingroup members (Hein et al., 2010; Mathur et al., 2010)”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites Hein et al., 2010 source

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    Premisecitation

    Recent research reported increased levels of urinary oxytocin in chimpanzees immediately before and during border patrols and intergroup encounters.

    “Finally, at the hormone level, recent research reported increased levels of urinary oxytocin (OT) — a nine-amino-acid peptide synthesized in hypothalamic cells — in chimpanzees immediately before and during border patrols and intergroup encounters (Samuni et al., 2017).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Samuni et al., 2017 source

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  • Classified as probably not a substantial claim. May combine two claims.

    Premisecitation

    Intranasal administration of OT (vs. placebo) in humans enhanced both empathic neural responses to ingroup pain and individuals' contributions to ingroup payoffs.

    “Likewise, intranasal administration of OT (vs. placebo) in humans enhanced both empathic neural responses to ingroup pain (Sheng et al., 2013) and individuals’ contributions to ingroup payoffs (De Dreu et al., 2010; De Dreu, 2010).”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites Sheng et al., 2013 source

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    • cites De Dreu et al., 2010

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  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Revenge often occurs between families or clans when an outgroup member brings harm to an ingroup member, which induces retaliation upon outgroup members.

    “Revenge often occurs between families or clans when an outgroup member brings harm to an ingroup member which, in turn, induces retaliation upon outgroup members (Ericksen and Horton, 1992).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Ericksen and Horton, 1992

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    Study design and conductown data

    Ingroup favoritism in attitudes, emotions, and punishment tendencies did not differ significantly between the Revenge and Control groups and between the involved and uninvolved targets.

    “Importantly, ingroup favoritism in attitudes, emotions, and punishment tendencies did not differ significantly between the Revenge and Control groups and between the involved and uninvolved targets (see Supplementary file 2 for statistical details).”
    Quote in the paperSubstantial claim

  • The quote only partly states this claim.

    Interpretationown data

    Intergroup conflict enhanced the link between endogenous OT at Time-1 and mPFC activity to Involved_Ingroup pain.

    “Together, these results suggest that intergroup conflict enhanced the link between endogenous OT measured after the initial experience of ingroup conflict and mPFC activity in response to the perceived pain of the ingroup member who was directly involved in conflict with an outgroup member.”
    Quote in the paperSubstantial claim

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    Study design and conductcitation

    The sample size was estimated using G*Power.

    “The sample size was estimated using G*Power (Faul et al., 2009).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Faul et al., 2009 source

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    Study design and conductnone given

    Revenge tendencies were estimated by self-reports.

    “Although our measures of endogenous OT and brain activity suggest that the association between endogenous OT and mPFC activity in response to perceived ingroup suffering is related to revenge tendencies, we noted that the latter were estimated by self-reports.”
    Quote in the paperSubstantial claim

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    Study design and conductreasoning

    Whole-brain analyses were used so as to not bias OT association with a specific network.

    “Whole-brain analyses were used so as to not bias OT association with a specific network (e.g., the empathy or theory-of-mind network).”
    Quote in the paperSubstantial claim

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    Interpretationown data

    These findings are consistent with the observations in chimpanzees and provide empirical evidence that intergroup conflict in primates including humans is associated with increased levels of endogenous OT.

    “These findings are consistent with the observations in chimpanzees (Samuni et al., 2017), and provide empirical evidence that intergroup conflict in primates including humans is associated with increased levels of endogenous OT.”
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    • cites Samuni et al., 2017 source

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    Study design and conductown data

    Participants were randomly assigned to two groups.

    “The participants were informed that they would be divided into two groups on the basis of the results of questionnaire measures, though they were actually randomly assigned to two groups so that there were one confederate and two participants in each group.”
    Quote in the paperNot a substantial claim

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    Study design and conductnone given

    Experimental protocols were approved by the Research Ethics Committee at the School of Psychological and Cognitive Sciences, Peking University, complying with the Declaration of Helsinki.

    “Experimental protocols were approved by the Research Ethics Committee at the School of Psychological and Cognitive Sciences (#2015-12-04), Peking University, complying with the Declaration of Helsinki.”
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    Study design and conductnone given

    Informed consent was obtained from all participants prior to the experiment.

    “Informed consent was obtained from all participants prior to the experiment.”
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    Study design and conductreasoning

    A total sample size of 28 was required to detect a significant interaction between Time and Group.

    “To detect a significant interaction between Time and Group required a total sample size of 28 with an error probability of 0.05 and power of 0.8, given the correlation among repeated measures (0.5) and the nonsphericity correction (1).”
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    Premisecitation

    The mPFC is well-known for its functional role in representing mental states, social emotion, and group identity.

    “The mPFC is well-known for its functional role in representing mental states (Amodio and Frith, 2006), social emotion (Harris and Fiske, 2007; Mathur et al., 2010), and group identity (Volz et al., 2009; Molenberghs and Morrison, 2014).”
    Quote in the paperNot a substantial claim0 of 3 sources checked
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    Study design and conductown data

    Four participants from each group were excluded from fMRI data analyses due to excessive head movements, leaving 40 participants in each group.

    “Four participants from each group were excluded from fMRI data analyses due to their excessive head movements during scanning, leaving 40 participants in each group being included for data analyses”
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    Premisecitation

    The salivary OT level in humans is affected by affiliative contact and is interrelated with the plasma OT level.

    “The salivary OT level in humans is affected by affiliative contact and is interrelated with the plasma OT level (Feldman et al., 2011).”
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    Study design and conductreasoning

    A total sample size of 86 was required to detect a significant main effect of Group.

    “To detect a significant main effect of Group required a total sample size of 86 with an error probability of 0.05 and power of 0.8, given the correlation among repeated measures (0.5).”
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    Premisecitation

    Bootstrapping supplies superior confidence intervals that are bias-corrected and accelerated.

    “Moreover, this procedure supplies superior confidence intervals (CIs) that are bias-corrected and accelerated (Preacher et al., 2007; Preacher and Hayes, 2008a; Preacher and Hayes, 2008b).”
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    Premisecitation

    Schadenfreude has been linked to striatum activation induced by misfortunes happening to envied persons.

    “Schadenfreude has been linked to striatum activation induced by misfortunes happening to envied persons (Takahashi et al., 2009).”
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    Study design and conductnone given

    Ingroup bias in closeness, emotions and attitudes were entered into the model as covariates.

    “In addition, ingroup bias in closeness, emotions and attitudes were entered into the model as covariates.”
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    Premisecitation

    To establish mediation, the path c' is not required to be significant.

    “To establish the mediation, the path c' is not required to be significant, and the only requirement is that the indirect effect a x b is significant.”
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    Study design and conductnone given

    The relationship between left/right buttons and ingroup/outgroup members was counter-balanced across participants.

    “(the relationship between left/right buttons and ingroup/outgroup members was counter-balanced across participants).”
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    Premisecitation

    The effect size of brain activities in response to others' suffering was between 0.39 and 0.84.

    “On the basis of the previous fMRI study of empathy for pain (Han et al., 2017), the effect size of brain activities (including aMCC, bilateral AI and bilateral SII) in response to others' suffering was between 0.39 and 0.84 (a middle effect size).”
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    • cites Han et al., 2017 source

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    Study design and conductnone given

    The GLMs included the realignment parameters to account for any residual movement-related effect.

    “The GLMs included the realignment parameters to account for any residual movement-related effect.”
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    Premisecitation

    The only requirement to establish mediation is that the indirect effect a x b is significant.

    “To establish the mediation, the path c' is not required to be significant, and the only requirement is that the indirect effect a x b is significant.”
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    Premisereasoning

    Bootstrapping uses the empirical sampling distribution to calculate p-values and to construct confidence intervals.

    “Rather than imposing questionable distributional assumptions, bootstrapping generates an empirical approximation of the sampling distribution of a statistic by repeated random resampling from the available data, and uses this distribution to calculate p-values and to construct confidence intervals.”
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    Premisecitation

    Intergroup conflict plays a substantial role in the evolution of both aggressiveness against outgroup and cooperativeness towards ingroups.

    “Intergroup conflict plays a substantial role in the evolution of both aggressiveness against outgroup and cooperativeness towards ingroups (Rusch, 2014).”
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    • cites Rusch, 2014 source

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    Study design and conductnone given

    The procedure was programmed so that both Uninvolved_Ingroup and Uninvolved_Outgroup targets showed painful expressions in half of the trials and neutral expressions in the other trials.

    “The procedure was programmed so that both Uninvolved_Ingroup and Uninvolved_Outgroup targets showed painful expressions in half of the trials and showed neutral expressions in the other trials.”
    Quote in the paperSubstantial claim

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    Study design and conductnone given

    The procedure was programmed so that both Involved_Ingroup and Involved_Outgroup targets lost the game in half of the trials and, when losing, received painful shocks in half of the trials and non-painful shocks in the other trials.

    “The procedure was programmed so that both the Involved_Ingroup and the Involved_Outgroup targets lost the game in half of the trials and, when losing the game, received painful shocks in half of the trials and non-painful shocks in the other trials.”
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    Study design and conductown data

    Owing to failure of OT measurements on a few participants, 37 and 40 participants were left in the Revenge and Control groups, respectively, for all further analyses related to OT levels.

    “Owing to the failure of OT measurements on a few participants, 37 and 40 participants were left in the Revenge and Control groups, respectively, for all further analyses related to OT levels.”
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    Premisecitation

    The oxytocinergic system is involved in modulating multiple social emotions that are either positively or negatively related to social behaviors.

    “Increasing evidence suggests that the oxytocinergic system is involved in modulating multiple social emotions that are either positively (e.g., empathy, Sheng et al., 2013) or negatively (e.g., schadenfreude, Shamay-Tsoory et al., 2009) related to social behaviors.”
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    Premisecitation

    Previous research has shown that viewing outgroup pain can activate the nucleus accumbens and greater NAcc activity predicted less motivation to help outgroup members.

    “Although previous research has shown that viewing outgroup pain can activate the nucleus accumbens (NAcc) and greater NAcc activity predicted less motivation to help outgroup members (Hein et al., 2010; Luo et al., 2015)”
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    Study design and conductnone given

    The trials in which a target received painful or non-painful shocks were presented in a random order.

    “The trials in which a target received painful or non-painful shocks were presented in a random order.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing).

    Premisenone given

    Rather than imposing questionable distributional assumptions, bootstrapping generates an empirical approximation of the sampling distribution of a statistic by repeated random resampling from the available data.

    “Rather than imposing questionable distributional assumptions, bootstrapping generates an empirical approximation of the sampling distribution of a statistic by repeated random resampling from the available data, and uses this distribution to calculate p-values and to construct confidence intervals.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    The order of the four scans in each session was counterbalanced across participants.

    “The order of the four scans in each session was counterbalanced across participants.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Study design and conductown data

    ROI coordinates were defined independently using a leave-one-out test with 79 of the 80 participants from the two subject groups.

    “To define the coordinates of ROIs independently, a leave-one-out test in which whole-brain analyses of the contrast of painful vs. neutral expressions which collapsed all the targets was conducted using 79 of the 80 participants from the two subject groups using a combined voxel-level threshold of p<0.001, uncorrected and cluster-level threshold of p<0.05, FWE corrected.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Given a significant indirect effect, if Path c is insignificant, the mediation is classified as indirect-only mediation.

    “Given a significant indirect effect, if Path c is insignificant, the mediation is classified as indirect-only mediation, which is the strongest full mediation (Kenny et al., 1998; Zhao et al., 2010).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites Kenny et al., 1998 source

      Not checked in the free run.

    • cites Zhao et al., 2010 source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductreasoning

    40 subjects in each group were included in further fMRI data analysis.

    “Hence, 40 subjects in each group were included in further fMRI data analysis”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data

    Four participants from each group were excluded from fMRI data analysis because their head movements exceeded 5 mm.

    “Four participants from each group (i.e., Revenge and Control groups) were excluded from fMRI data analysis because their head movements exceeded 5 mm.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductcitation

    OT measurements were performed in duplicate according to the kit's instructions.

    “Measurements were performed in duplicate according to the kit’s instructions, similar to the procedures used in previous studies (van Ijzendoorn et al., 2012; Bhandari et al., 2014; Tsuji et al., 2015).”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites van Ijzendoorn et al., 2012 source

      Not checked in the free run.

    • cites Bhandari et al., 2014 source

      Not checked in the free run.

    • cites Tsuji et al., 2015 source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Study design and conductnone given

    fMRI data analysis was identical for the Revenge and Control groups.

    “which was identical for the Revenge and Control groups.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    The order of the rating tasks was counter-balanced across participants.

    “The order of the rating tasks was counter-balanced across participants.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Premisecitation

    Recent research has shown that willingness to punish severely was associated with increased amygdala activity in third-party punishment.

    “recent research has shown that, in a scenario in which an observer punishes transgressors due to social norm violation (i.e., third-party punishment), the willingness to punish severely was associated with increased amygdala activity (Stallen et al., 2018)”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Stallen et al., 2018 source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Indirect-only mediation is the strongest full mediation.

    “Given a significant indirect effect, if Path c is insignificant, the mediation is classified as indirect-only mediation, which is the strongest full mediation (Kenny et al., 1998; Zhao et al., 2010).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites Kenny et al., 1998 source

      Not checked in the free run.

    • cites Zhao et al., 2010 source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    Padded clamps were used to minimize head motion.

    “Padded clamps were used to minimize head motion and earplugs were used to attenuate scanner noise.”
    Quote in the paperNot a substantial claim
59 of 59

  • The paper relies on this without support.

    Salivary oxytocin levels reflect endogenous central oxytocin activity.

    “We measured participants' salivary levels of OT, brain responses to perceived ingroup pain, and revenge propensity to bring physical harm to the outgroup.”

  • The paper relies on this without support.

    The painful electric shocks used in the paradigm are experienced as painful by the targets.

    “the winner gave painful or non-painful electric shocks to the rival”

  • The paper relies on this without support.

    Participants' self-reported willingness to give painful shocks reflects their actual revenge propensity.

    “After fMRI scanning, the participants were asked to report how willing they were to punish a target by giving painful shocks (1 = not painful at all, 9 = extremely painful) to estimate their tendencies to punish outgroup members.”

  • The paper relies on this without support.

    The experimental paradigm simulates real-life revenge during intergroup conflict.

    “Toward these ends, we developed a new neural-behavioral paradigm that simulates real-life revenge during intergroup conflict.”

  • The paper relies on this without support.

    Revenge behavior is universal and highly costly.

    “Revenge behavior is universal and highly costly.”

  • The paper relies on this without support.

    Revenge behavior during intergroup conflict engages multiple psychological processes from perceiving ingroup suffering to making aggressive decisions toward outgroups.

    “Revenge behavior during intergroup conflict engages multiple psychological processes from perceiving ingroup suffering to making aggressive decisions toward outgroups.”
6 of 6

Statistics that don’t add up

Each reported p-value recomputed from its test statistic and degrees of freedom.

  • Inconsistent p-value: F(1,65)=5.70, p = .03

    Minor

    The paper reports p = .03 here; recomputing from the test statistic and its degrees of freedom gives p = .020. The check cannot tell whether the statistic or the p-value is the misprint.

    Reported p = .03 · recomputed p = .020

1 of 1

Statistics recomputed

Every reported test result, recomputed from its test statistic and degrees of freedom. A result shows as not adding up only once an independent check has confirmed it.

  • Doesn’t add upF(1, 65) = 5.7reported p = .03 · recomputed p = .020

    “F(1,65)=5.70, p = .03”

  • Not confirmedF(1, 78) = 8.21reported p = .006 · recomputed p = .005

    “F(1,78) = 8.21, p = .006”

  • Not confirmedF(1, 78) = 5.37reported p = .026 · recomputed p = .023

    “F(1,78) = 5.37, p = .026”

  • ConsistentF(1, 86) = 136.23reported p < .001 · recomputed p < .001

    “F(1,86) = 136.23, p < .001”

  • ConsistentF(1, 78) = 9.68reported p = .004 · recomputed p = .003

    “F(1,78) = 9.68, p = .004”

    The paper states a correction for multiple tests

  • ConsistentF(1, 78) = 3.95reported p = .05 · recomputed p = .050

    “F(1,78) = 3.95, p = .050”

  • ConsistentF(1, 78) = 14.91reported p < .002 · recomputed p < .001

    “F(1,78) = 14.91, p < .002”

  • ConsistentF(1, 78) = 28.62reported p < .002 · recomputed p < .001

    “F(1,78) = 28.62, p < .002”

  • ConsistentF(1, 78) = 23.57reported p < .002 · recomputed p < .001

    “F(1,78) = 23.57, p < .002”

  • ConsistentF(1, 78) = 27.19reported p < .002 · recomputed p < .001

    “F(1,78) = 27.19, p < .002”

  • ConsistentF(1, 78) = 5.65reported p = .02 · recomputed p = .020

    “F(1,78) = 5.65, p = .020”

  • ConsistentF(1, 78) = 19.21reported p < .001 · recomputed p < .001

    “F(1,78) = 19.21, p < .001”

  • Consistentt(39) = -1.58reported p = .123 · recomputed p = .122

    “t(39) = −1.58, p = .123”

  • Consistentt(39) = 4.39reported p < .001 · recomputed p < .001

    “t(39) = 4.39, p < .001”

  • ConsistentF(1, 67) = 22.66reported p < .001 · recomputed p < .001

    “F(1,67) = 22.66, p < .001”

  • ConsistentF(2, 134) = 4.04reported p = .02 · recomputed p = .020

    “F(2,134) = 4.04, p = .020”

  • ConsistentF(1, 78) = 5.41reported p = .036 · recomputed p = .023

    “F(1,78) = 5.41, p = .036”

    The paper states a correction for multiple tests

  • ConsistentF(1, 78) = 4.56reported p = .036 · recomputed p = .036

    “F(1,78) = 4.56, p = .036”

  • ConsistentF(1, 78) = 3.92reported p = .102 · recomputed p = .051

    “F(1,78) = 3.92, p = .102”

    The paper states a correction for multiple tests

  • ConsistentF(1, 78) = 1.45reported p = .232 · recomputed p = .232

    “F(1,78) = 1.45, p = .232”

  • ConsistentF(1, 78) = 0.09reported p = .77 · recomputed p = .765

    “F(1, 78)=0.09, p = .770”

  • ConsistentF(1, 78) = 0.13reported p = .716 · recomputed p = .719

    “F(1, 78)=0.13, p = .716”

  • ConsistentF(1, 78) = 2.71reported p = .104 · recomputed p = .104

    “F(1,78) = 2.71, p = .104”

  • ConsistentF(1, 78) = 2.68reported p = .105 · recomputed p = .106

    “F(1,78) = 2.68, p = .105”

  • ConsistentF(1, 75) = 12.99reported p < .001 · recomputed p < .001

    “F(1, 75)=12.99, p < .001”

  • Consistentt(35) = 0.94reported p = .355 · recomputed p = .354

    “t(35) = 0.94, p = .355”

  • Consistentt(35) = 3.41reported p = .002 · recomputed p = .002

    “t(35) = 3.41, p = .002”

  • Consistentt(34) = 2.05reported p = .048 · recomputed p = .048

    “t(34) = 2.05, p = .048”

  • Consistentt(34) = -0.17reported p = .863 · recomputed p = .866

    “t(34) = −0.17, p = .863”

  • Consistentt(35) = 0.7reported p = .488 · recomputed p = .489

    “t(35) = 0.70, p = .488”

  • Consistentt(34) = 2.8reported p = .008 · recomputed p = .008

    “t(34) = 2.80, p = .008”

  • Consistentt(34) = -0.74reported p = .467 · recomputed p = .464

    “t(34) = −0.74, p = .467”

32 of 32

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Second saliva collection is labeled Time-3 instead of Time-2

    Minor

    The methods label both the second and third saliva collections Time-3. Elsewhere, the collection immediately after scanning is designated Time 2, and the collection 15 minutes later is Time 3.

1 of 1

The citation lists haven’t been fetched yet

References 87 · Cited by 58

Research works printed but not linked: 1

  1. Allport, 1954, The Nature of Prejudice

Authors
Han, X., Gelfand, M. J., Wu, B., Zhang, T., Li, W., Gao, T., Pang, C., Wu, T., Zhou, Y., Zhou, S., Wu, X., & Han, S.
Affiliations
  • Peking University (CN)
  • University of Maryland, College Park (US)
  • Chinese PLA General Hospital (CN)
Corresponding author
  • Wu, Xinhuai
  • Han, Shihui
ORCID
Venue
eLife
Publisher
eLife Sciences Publications, Ltd
Published
2020-03-03
Volume
9
ISSN
2050-084X (ISSN-L)
DOI
10.7554/elife.52014
PMC
PMC7058385
OpenAlex
W3010642434
Semantic Scholar
bd2a627acb7e31c93c93319286a0bad9cae78d6e
Cited by
58
References
87
Citations by year
2026: 2 · 2025: 1 · 2024: 4 · 2023: 3 · 2022: 5 · 2021: 7 · 2020: 36
FWCI
13.94
Type
journal article
Language
en
Open access
Licence
Locations
  • eLife (publishedVersion, cc-by)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
Funders
National Natural Science Foundation of China (31661143039, 31421003, 31470986)
Topics
  • Social Sciences › Psychology › Social Psychology › Neuroendocrine regulation and behavior
  • Social Sciences › Sociology and Political Science › Social and Intergroup Psychology
  • Social Sciences › Psychology › Social Psychology › Emotions and Moral Behavior
Keywords
revenge, intergroup conflict, oxytocin, medial prefrontal cortex, electric shock punishment, conflict contagion, social pain, functional MRI
MeSH terms
Adult, Conflict, Psychological, Female, Group Processes, Humans, Magnetic Resonance Imaging, Male, Neurobiology, Oxytocin, Young Adult

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-09.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-09.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

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