所有社会体系中的人都会形成及参与协作联盟。要想成功融入这种结盟社会体系，个体要能及时发觉新联合和联盟的兴起，并在这些潜在同盟种类中预估哪些目前正在发起互动。我们表示进化使我们的大脑武装了认知机制，它专门用于实现这些功能：即结盟检测系统。该观点认为，种族分类并不是因（个体）可明显感知分辨的外表而存在，而是因产生自种族预示社会联盟和分裂的环境中的联盟系统而形成且受其管理。使运用对抗性联盟的早期试验表明，人脑能自发检测哪些个体正与己协作对抗共敌，且基于合作与竞争的模式而潜在地按人分配竞争的联盟类别。但是否社会性对立是通过联盟方式触发人类划分的必须条件呢？即我们仅因为认知上A，B共同与C和D起冲突就将他们联合划分为同类？我们报告的新研究表明，和平协作可以触发对新联合联盟的觉察并使得种族分别因关联而淡化。联盟并不需要按集体色彩或其他易感知的显着线索被标记。当种族分别没有预示发展中的联盟结构时，关于协作活动的行为线索会通过联合进行正调节，通过种族而进行负调节，有时则使之消除。由联合和种族来敏锐地调节分类的联盟线索对分类不产生性别差异上的影响，这消除了许多对结果的替代性解释。研究结果证实了这一假设，即通过种族将人们分类是认知系统下产生的可逆性副产品，该系统专门进行检测联盟类别并规范其使用。共同敌人没必要消除重要的社会界限; 和平协作可以产生同样效果。
Abstract
Humans in all societies form and participate in cooperative alliances. To successfully navigate an alliance-laced world, the human mind needs to detect new coalitions and alliances as they emerge, and predict which of many potential alliance categories are currently organizing an interaction. We propose that evolution has equipped the mind with cognitive machinery that is specialized for performing these functions: an alliance detection system. In this view, racial categories do not exist because skin color is perceptually salient; they are constructed and regulated by the alliance system in environments where race predicts social alliances and divisions. Early tests using adversarial alliances showed that the mind spontaneously detects which individuals are cooperating against a common enemy, implicitly assigning people to rival alliance categories based on patterns of cooperation and competition. But is social antagonism necessary to trigger the categorization of people by alliance—that is, do we cognitively link A and B into an alliance category only because they are jointly in conflict with C and D? We report new studies demonstrating that peaceful cooperation can trigger the detection of new coalitional alliances and make race fade in relevance. Alliances did not need to be marked by team colors or other perceptually salient cues. When race did not predict the ongoing alliance structure, behavioral cues about cooperative activities up-regulated categorization by coalition and down-regulated categorization by race, sometimes eliminating it. Alliance cues that sensitively regulated categorization by coalition and race had no effect on categorization by sex, eliminating many alternative explanations for the results. The results support the hypothesis that categorizing people by their race is a reversible product of a cognitive system specialized for detecting alliance categories and regulating their use. Common enemies are not necessary to erase important social boundaries; peaceful cooperation can have the same effect.
Humans in all societies form and participate in cooperative alliances. To successfully navigate an alliance-laced world, the human mind needs to detect new coalitions and alliances as they emerge, and predict which of many potential alliance categories are currently organizing an interaction. We propose that evolution has equipped the mind with cognitive machinery that is specialized for performing these functions: an alliance detection system. In this view, racial categories do not exist because skin color is perceptually salient; they are constructed and regulated by the alliance system in environments where race predicts social alliances and divisions. Early tests using adversarial alliances showed that the mind spontaneously detects which individuals are cooperating against a common enemy, implicitly assigning people to rival alliance categories based on patterns of cooperation and competition. But is social antagonism necessary to trigger the categorization of people by alliance—that is, do we cognitively link A and B into an alliance category only because they are jointly in conflict with C and D? We report new studies demonstrating that peaceful cooperation can trigger the detection of new coalitional alliances and make race fade in relevance. Alliances did not need to be marked by team colors or other perceptually salient cues. When race did not predict the ongoing alliance structure, behavioral cues about cooperative activities up-regulated categorization by coalition and down-regulated categorization by race, sometimes eliminating it. Alliance cues that sensitively regulated categorization by coalition and race had no effect on categorization by sex, eliminating many alternative explanations for the results. The results support the hypothesis that categorizing people by their race is a reversible product of a cognitive system specialized for detecting alliance categories and regulating their use. Common enemies are not necessary to erase important social boundaries; peaceful cooperation can have the same effect.