Political conflict between American Democrats and Republicans and ethnoreligious conflict between Israelis and Palestinians seem intractable, despite the availability of reasonable compromise solutions in both cases. This research demonstrates a fundamental cognitive bias driving such conflict intractability: Adversaries attribute their ingroup’s actions to ingroup love more than outgroup hate and attribute their outgroup’s actions to outgroup hate more than ingroup love. This biased attributional pattern increases beliefs and intentions associated with conflict intractability, including unwillingness to negotiate and unwillingness to vote for compromise solutions. In addition, offering financial incentives for accuracy in evaluating one’s outgroup mitigates this biased attributional pattern and its consequences. Understanding this bias and how to alleviate it can contribute to conflict resolution on a global scale.

Five studies across cultures involving 661 American Democrats and Republicans, 995 Israelis, and 1,266 Palestinians provide previously unidentified evidence of a fundamental bias, what we term the “motive attribution asymmetry,” driving seemingly intractable human conflict. These studies show that in political and ethnoreligious intergroup conflict, adversaries tend to attribute their own group’s aggression to ingroup love more than outgroup hate and to attribute their outgroup’s aggression to outgroup hate more than ingroup love. Study 1 demonstrates that American Democrats and Republicans attribute their own party’s involvement in conflict to ingroup love more than outgroup hate but attribute the opposing party’s involvement to outgroup hate more than ingroup love. Studies 2 and 3 demonstrate this biased attributional pattern for Israelis and Palestinians evaluating their own group and the opposing group’s involvement in the current regional conflict. Study 4 demonstrates in an Israeli population that this bias increases beliefs and intentions associated with conflict intractability toward Palestinians. Finally, study 5 demonstrates, in the context of American political conflict, that offering Democrats and Republicans financial incentives for accuracy in evaluating the opposing party can mitigate this bias and its consequences. Although people find it difficult to explain their adversaries’ actions in terms of love and affiliation, we suggest that recognizing this attributional bias and how to reduce it can contribute to reducing human conflict on a global scale.

Many human conflicts appear extraordinarily difficult to resolve even when outsiders can see the contours of a rational resolution. Ideological opponents risk the health of their economies and their planet because they are unable to make political compromises. Ethnic and religious groups across the world engage in mass acts of violence, rejecting solutions of mutual benefit that involve sharing power, land, or religious sites. Why are so many conflicts so intractable when people on both sides could gain from a compromise?

Approaches to this question typically center on the complexity and profundity of the issues involved and each side’s construal of the conflict (1, 2). An additional, deeper barrier to conflict resolution may be simple pessimism toward compromise. If adversaries believe inflexibility on the other side renders mutual compromise impossible, they will be unlikely to adopt seemingly rational strategies for conciliation (3). In other words, the perception of conflict intractability may be an independent cause of a stalemate. Here, we identify a fundamental cognitive bias that contributes to the belief in conflict intractability, and may therefore contribute to conflict spirals (4⇓–6).

We predict and observe that people often attribute their outgroup’s actions during conflict to hatred. This attribution occurs despite evidence that intergroup aggression stems at least as much, if not more, from ingroup love (7⇓⇓⇓⇓⇓–13). We hypothesized that whereas people can clearly identify ingroup love as the source of their own group’s engagement in conflict (14), when attempting to explain their outgroup’s actions, people focus on dislike (15) and “why they hate us” (16). Expanding on prior research, we propose a previously untested hypothesis: People will attribute ingroup engagement in conflict to love more than hate, but they will attribute outgroup engagement in conflict to hate more than love. We term this pattern the “motive attribution asymmetry” and document this bias across five studies among American Democrats and Republicans as well as Palestinians and Israelis, demonstrating consequences of this bias that further fuel intergroup conflict. We use the term “bias” to mean response tendency (rather than error); in this case, a tendency to attribute love vs. hate to one’s ingroup to a greater degree than to one’s outgroup and to attribute hate vs. love to one’s outgroup to a greater degree than to one’s ingroup.

These studies provide a number of contributions:

iv) The studies themselves contain numerous previously unexamined features, investigating this phenomenon in diverse linguistic and political contexts, examining different types of real intergroup conflicts (one intensely ideological yet predominantly nonviolent and the other ethnoreligious and chronically violent), characterizing previously unexamined consequences of this attributional bias, and establishing a manipulation aimed at mitigating this bias and its effects.

Results and Discussion

Study 1 randomly assigned American Democrats and Republicans (n = 285) to rate the motives for engaging in conflict, in terms of love and hate, of either their own party or the other party. A 2 (target: own party vs. other party) × 2 (motive: love vs. hate) mixed ANOVA revealed a target X motive interaction [F(1, 283) = 83.57, P < 0.0001, η2 P = 0.23], with no main effects for condition (P = 0.97) or motive (P = 0.36). Follow-up t tests revealed that all simple effects in the condition × motive interaction were significant (t > 5.63, P < 0.0001, d ≥ 0.73). People indicated that their own party was more motivated by love for their own party [mean (M) = 4.47, standard deviation (SD) = 1.31] than by hate for the other party (M = 3.63, SD = 1.17) and that the opposing party was more motivated by hate (M = 4.56, SD = 1.10) than love (M = 3.53, SD = 1.27). In brief, these findings represent a fundamental discrepancy between how people view the motives of their own political party and the motives of the opposing political party (Fig. S1).

Studies 2 and 3 investigated whether this bias would replicate across cultures and in the context of a protracted violent conflict: the Israeli-Palestinian dispute. These studies used a within-subjects rather than between-subjects design such that all participants answered questions both for their own group and for the other side. We asked representative samples of Israelis (study 2, n = 497) and Palestinians living in the West Bank and Gaza (study 3, n = 1,266) why many Israelis and Palestinians supported violence in the conflict across the border of Gaza and Israel. Scale items and forced-choice items asked participants the extent to which they saw aggression committed by Israelis and aggression committed by Palestinians as driven by love and by hate.

In study 2 with the Israeli population, a 2 (target: Israel vs. Palestine) × 2 (motive: love vs. hate) ANOVA on the scale items revealed no main effect for target (P = 0.28) but a main effect for motive such that participants reported hate (M = 2.79, SD = 0.71) as a more likely motive than love (M = 2.65, SD = 0.80) for both populations [F(1, 399) = 7.64, P = 0.006, η2 P = 0.02]. This main effect was qualified by a target × motive interaction [F(1, 399) = 392.56, P < 0.0001, η2 P = 0.50].

Follow-up t tests on the initial ANOVA revealed that all simple effects in the target × motive interaction were significant (t ≥ 11.69, P < 0.0001, d ≥ 1.78). Israelis reported they were motivated by love for Israelis (M = 3.10, SD = 1.04) more than by hate for Palestinians (M = 2.30, SD = 1.00) and believed that Palestinians were driven by hate for Israelis (M = 3.27, SD = 0.88) more than by love for Palestinians (M = 2.23, SD = 1.09). In addition, Israelis believed love was a stronger motive for Israelis than for Palestinians and hate was a stronger motive for Palestinians than for Israelis (Fig. 1). The forced-choice questions revealed the same pattern (SI Materials and Methods).

Fig. 1. Israelis’ attributions to Israelis and Palestinians in study 2. Means and SEs are taken from the total sample rather than from specific tests that exclude subjects who responded “don’t know/not applicable.” Error bars represent SEs.

In study 3 with the Palestinian population, a 2 (target: Israel vs. Palestine) × 2 (motive: love vs. hate) ANOVA on the four scale items revealed a main effect for target, with higher ratings for Palestinians than for Israelis (M = 3.32, SD = 0.52 vs. M = 3.11, SD = 0.52) [F(1, 1,221) = 163.15, P < 0.0001, η2 P = 0.12], and a main effect for motive, with higher ratings for hate than for love (M = 3.38, SD = 0.50 vs. M = 3.06, SD = 0.56) [F(1, 1,221) = 329.29, P < 0.0001, η2 P = 0.21]. More importantly, these main effects were qualified by a target × motive interaction [F(1, 1,221) = 374.31, P < 0.0001, η2 P = 0.24].

Follow-up t tests on the initial ANOVA revealed that all simple effects in the target × motive interaction were significant (t > 2.19, P ≤ 0.028, d ≥ 0.17). Palestinians indicated they were motivated by love (M = 3.34, SD = 0.69) more than hate (M = 3.29, SD = 0.66) and believed that Israelis were driven by hate (M = 3.45, SD = 0.57) more than love (M = 2.77, SD = 0.82). In addition, Palestinians believed love was a stronger motive for Palestinians than for Israelis and hate was a stronger motive for Israelis than for Palestinians (Fig. 2). The forced-choice questions revealed the same pattern (SI Materials and Methods).

Fig. 2. Palestinians’ attributions to Israelis and Palestinians in study 3. Means and SEs are taken from the total sample rather than from specific tests that exclude subjects who responded “don’t know/not applicable.” Error bars represent SEs.

From scores on the scale items and forced-choice items, the major qualitative difference between the Palestinian and Israeli populations appears to be that Palestinians state that they are driven by hate almost as much as love (although ratings of these motives are significantly different). Israelis, on the other hand, much more strongly distinguish between these two motives, stating that they are driven far more by love than hate. A 2 (population: Israeli vs. Palestinian) × 2 (target: Israeli vs. Palestinian) × 2 (motive: love vs. hate) ANOVA combining data from studies 2 and 3 confirms this difference, revealing a three-way population × target × motive interaction [F(1, 1,620) = 920.90, P < 0.0001, η2 p = 0.36]. (This effect and all others for which the results of Box’s test for equality of covariance matrices were significant across studies are unchanged compared with assuming sphericity.) It might be the case that in asymmetrical conflicts, for groups such as these Palestinians, who experience oppression and have relatively less power than Israelis, expressions of anger and hatred (in attempts to change the status quo) are more normative (17, 18). Nonetheless, these findings yet again represent a fundamental discrepancy between perceptions of one’s ingroup’s motives for conflict and perceptions of one’s outgroup’s motives for conflict.

We theorized that this motive attribution asymmetry may be associated with specific beliefs that undermine conflict resolution, including a belief in the unalterable intransigence of the outgroup (3). Thus, the primary aim of study 4 was to examine the implications of the tendency demonstrated in studies 1–3 for people to attribute the outgroup’s motives for conflict to outgroup hate more than ingroup love. Hatred is a highly persistent and passionate dislike associated with a belief that the hated object is evil (19). Because hatred is associated with the belief that the other is bad in nature (i.e., is essentialized as evil), it leads to an inclination not to change the other but to separate from or destroy the other (19, 20). Thus, we predicted that attributions of outgroup aggression to hate for the outgroup rather than love for the aggressors’ ingroup would be associated with beliefs and intentions associated with conflict intractability (e.g., unwillingness to negotiate, pessimism that a peace deal can be attained). To test this hypothesis, we recruited another representative sample of Israelis (n = 498) and asked them to rate the extent to which they believed that Palestinian violence was motivated by love for Palestine and by hatred of Israel. We also asked them about beliefs and intentions associated with conflict intractability across three different versions of instructions that did not affect results (SI Materials and Methods).

Israelis again attributed Palestinian support for conflict to hate (M = 3.29, SD = 0.95) more than love (M = 2.52, SD = 1.14) [t(430) = 12.70, P < 0.0001, d = 1.65]. The forced-choice item revealed the same pattern (SI Materials and Methods). Having determined that the general outgroup attribution bias replicates, we next turned to other variables of interest to examine the implications of this bias.

From the scale items, we computed a measure of attributional bias by subtracting scores for attribution of love from scores for attribution of hate to produce a difference score. We then standardized this difference score, standardized people’s responses on the forced-choice love-vs.-hate item (love = 1, hate = 2), and averaged these two standardized items [r(392) = 0.36, P < 0.0001] to produce a bias score. This score includes people without a difference score or forced-choice item response because of responding, “don’t know/not applicable.” Analyses excluding these people reveal comparable relationships between bias and the various implications measures. Higher bias scores mean a greater perception that Palestinians are motivated by hate vs. love (separate analyses of love attributions, hate attributions, and forced-choice attributions are provided in SI Materials and Methods). This measure of bias was correlated with reduced willingness to negotiate [r(453) = −0.23, P < 0.0001], reduced perceptions of a win-win [r(409) = −0.21, P < 0.0001], reduced optimism [r(463) = −0.10, P = 0.038], reduced personal willingness to vote for a peace deal [r(471) = −0.15, P = 0.001], reduced expectation that Palestinians will vote for a peace deal [r(471) = −0.11, P = 0.016], reduced positive compromise outcome beliefs [r(471) = −0.26, P < 0.0001], and increased essentialist beliefs about Palestinians [r(471) = 0.27, P < 0.0001]. Unsurprisingly, bias was not correlated with beliefs about Israelis (expected Israeli voting for a peace deal and essentialist beliefs about Israelis: P > 0.10). From these findings, it is clear that this biased perception of one’s outgroup as driven by hate vs. love, a critical component of the motive attribution asymmetry, has significant consequences for beliefs and behavioral intentions.

Study 5 introduced an experimental manipulation designed to reduce the motive attribution asymmetry and consequent perceived conflict intractability. American Democrats and Republicans (n = 331) evaluated how much their own party is motivated by ingroup love (compassion and empathy toward their own party) and outgroup hate (dislike and animosity toward the opposing party). Then, participants were randomly assigned to an incentives condition that offered financial incentives for accurate evaluations of the outgroup or to a control condition that offered no incentives. All participants then evaluated how much the opposing party is motivated by ingroup love and outgroup hate on the same measures as for their own party. Then, all participants answered questions about their willingness to negotiate with the opposing party, optimism that a successful resolution could be reached, expectations for a win-win compromise, and essentialist beliefs toward the other party.

A 2 (condition: control vs. incentives) × 2 (target: own party vs. other party) × 2 (motive: love vs. hate) mixed ANOVA revealed a significant effect of target [F(1, 329) = 9.50, P = 0.002, η2 P = 0.03]; a significant motive × condition interaction [F(1, 329) = 12.33, P = 0.001, η2 P = 0.04]; a significant target × motive interaction [F(1, 329) = 54.34, P < 0.0001, η2 P = 0.14]; and, most importantly, a significant condition × target × motive interaction [F(1, 329) = 42.05, P = 0.001, η2 P = 0.11] (all other effects, P > 0.39). Replicating previous studies, overall participants attributed more love (M = 4.66, SD = 1.49) than hate (M = 4.09, SD = 1.54) to their own party [t(330) = 4.62, P < 0.0001, d = 0.84] and more hate (M = 4.81, SD = 1.70) than love (M = 4.29, SD = 1.71) to the opposing party [t(330) = 3.59, P < 0.0005, d = 0.68] (attributions of love to ingroup vs. love to outgroup and hate to ingroup vs. hate to outgroup differ significantly as well: P ≤ 0.0001). More importantly, examining attributions to the outgroup by experimental condition reveals that whereas participants in the control condition indeed attribute more hate (M = 5.27, SD = 1.62) than love (M = 3.89, SD = 1.65) to the opposing party [t(166) = 7.56, P < 0.0001, d = 1.89], in the incentives condition, attribution of hate diminishes significantly compared with the control condition (M = 4.35, SD = 1.67) [t(329) = 4.40, P < 0.0001, d = 0.49] and attribution of love increases significantly compared with the control condition (M = 4.70, SD = 1.69) [t(329) = 5.05, P < 0.0001, d = 0.56] such that the attributional pattern is reversed (Fig. 3).

Fig. 3. Comparison by condition of Democrats’ and Republicans’ attributions of love and hate to the opposing party in study 5. Error bars represent SEs.

To assess the impact of the motive attribution asymmetry on consequence measures, we computed a composite bias score by subtracting attributions of love to the outgroup from attributions of hate to the outgroup (separate analyses of love and hate attributions are provided in SI Materials and Methods). Significant correlations emerged such that bias reduced optimism [r(329) = −0.30, P < 0.0001], bias reduced perceptions of a win-win [r(329) = −0.16, P = 0.004], and bias increased essentialism [r(328) = 0.14, P = 0.014]. These findings largely replicate those findings of study 4, although willingness to negotiate was only slightly negatively related to bias (r = −0.05, P = 0.38). In addition, we computed a similar composite bias score for the ingroup by subtracting attributions of love to the ingroup from attributions of hate to the ingroup, and found this bias similarly correlated negatively with optimism [r(329) = −0.16, P = 0.003] and perceptions of a win-win [r(329) = −0.10, P = 0.065] and did not significantly affect willingness to negotiate (r = −0.04, P = 0.53) or essentialist beliefs (r = −0.01, P = 0.85). Although we did not have explicit predictions about the effect of ingroup attributions on consequence measures, these findings suggest that ingroup attributions have implications for conflict resolution as well.

It was also important to determine whether our manipulation affected these consequences measures so as to demonstrate that incentives for accuracy did not simply increase people’s willingness to infer the other side’s motivations momentarily (with no meaningful consequences for conflict intractability beliefs). Condition significantly influenced optimism such that incentives (M = 3.52, SD = 1.50) increased optimism compared with the control condition (M = 3.14, SD = 1.64) [t(329) = 2.17, P = 0.031, d = 0.24] and incentives (M = 2.86, SD = 0.84) reduced essentialist beliefs compared with the control condition (M = 3.08, SD = 0.93) [t(328) = 2.20, P = 0.028, d = 0.24]. Furthermore, bootstrapping mediation analysis (21) with condition coded as incentives = 1 and control = 0 (bias-corrected, 20,000 resamples) suggested that decreased biased attribution toward the outgroup (attributions of hate to the outgroup minus attributions of love to the outgroup) mediates the relationship between condition and optimism [95% confidence interval (CI) = 0.17–0.45; the path coefficients are illustrated in Fig. S2] and that attribution of hate to the outgroup and attribution of love to the outgroup separately appear to mediate this effect as well (95% CI = 0.13−0.40 and 95% CI = 0.02–0.21, respectively). An equivalent mediation analysis suggested that biased attribution toward the outgroup mediates the effect of condition on essentialist beliefs (95% CI = −0.13 to −0.0002; the path coefficients are illustrated in Fig. S2) and that attribution of hate to the outgroup separately appears to mediate this effect as well (95% CI = −0.20 to −0.06). In other words, incentives for accuracy increase optimism toward a mutual political agreement through simultaneously increasing attributions of love and decreasing attributions of hate toward the opposing political party. Incentives for accuracy also increase perceptions that the opposing political party is malleable through reducing this biased attribution pattern as well, primarily through reducing attributions of hate toward the opposing political party. Condition did not significantly affect willingness to negotiate (P = 0.30) or perceptions of a win-win (P = 0.17), although participants in the incentives condition did indicate increased willingness to negotiate and increased expectations for a win-win solution.

Although the effect of monetary incentives is robust in this context, in that incentives not only mitigate but actually reverse the motive attribution asymmetry, we acknowledge that the strength of this particular intervention might vary for conflicts of a more violent and volatile nature, and we welcome future research to test its effects.

Five studies document the first evidence, to our knowledge, of a motive attributional asymmetry whereby adversaries attribute their own support for aggression more to love than to hate but attribute the other group’s aggression more to hate than to love. By comparing attributions toward one’s outgroup with the outgroup’s attributions toward itself, we demonstrate for the first time, to our knowledge, that outgroup attributions of love vs. hate are biased, if not erroneous. Furthermore, this research illustrates important consequences of this attributional bias (e.g., willingness to negotiate, voting intentions, beliefs about compromise) and provides a manipulation of incentivizing accuracy to mitigate this attributional asymmetry, suggesting two mechanisms driving this asymmetry.

One potential mechanism concerns the cognitive availability of love vs. hate. Affiliative motives like love may be less observable in outgroup members than in ingroup members, especially during intergroup conflict. Expressions of love are more likely to occur in affiliative and familial settings than in the presence of ostensible competitors, whereas expressions of anger or aggression are more likely to emerge and capture attention in the presence of competitors (22, 23). Therefore, expressions of animosity (vs. expressions of love) may be more observable to people outside the group. This pattern of relative visibility between love and hate resembles the lack of awareness that drives other biases, such as the bias blind spot (24) and naive realism (1). Related to this misperception is the tendency for people to interpret others’ actions as approach-motivated even when recognizing their own actions to be avoidance-motivated (because approach motives seem more salient) (25). When people evaluate their enemies, they apparently link enemy actions to approach motives (toward the ingroup) rather than avoidance motives to protect their own.

A second potential mechanism underlying this asymmetry concerns motivation: People may engage in motivated reasoning to see their ingroups as loving and their outgroups as hateful. This attributional pattern bears conceptual similarity to the ultimate attribution error, whereby people attribute positive (negative) ingroup behaviors to internal (external) factors and to attribute outgroup positive (negative) behaviors to external (internal) factors (26). Importantly, the present work differs from this prior research because it examines evaluations of the same behavior (involvement in conflict) in terms of solely internal factors (i.e. motivations for love vs. hate) rather than examining evaluations of different behaviors (i.e. positive behaviors and negative behaviors) in terms of internal vs. external factors, yet a similar motivational component of this bias might be present in this bias and in the motive attribution asymmetry. The present bias also bears similarity to people's motivational tendency to deny prosocial values (e.g., love) to outgroup members to dehumanize them and justify harm toward them (27).

We believe our results, including those results of study 5, are consistent with both of these mechanisms. Monetary incentives can reduce egocentrism through increasing effortful perspective-taking (28), as well as motivating people to detect others’ emotions more accurately (29). Monetary incentives can thus increase effortful attention to the other side’s true underlying mental states and can increase motivation to assess others accurately (30). Future research can examine the separate contributions of these two mechanisms.

Overall, these results suggest that the motive attribution asymmetry is a significant barrier to resolution of intergroup conflict. Independent of factors such as divergent ideologies, clashing religious beliefs, or external economic crises, the biased attribution of an outgroup’s actions to hate makes disputants perceive conflict to be more intractable. Just as the overestimation of group differences leads to conflict escalation (31), failing to recognize love as a shared motive between one’s ingroup and outgroup likely exacerbates conflict as well. Furthermore, we speculate that this specific intergroup misperception is one that is particularly difficult to detect. Because constructs like love and loyalty hold such positive connotations, it is difficult to notice others’ affiliative motives as sources of conflict, similar to the difficulty of noticing others’ ingroup favoritism (rather than outgroup derogation) as a primary contributor to intergroup discrimination (32). Identifying this motive attribution asymmetry as a consequential source of conflict and identifying how to mitigate this attributional bias can contribute to reducing long-standing conflict.