What is the relationship between war propaganda and nationalism, and what are the effects of each on support for, or participation in, violent acts? This is an important question for international criminal law and ongoing speech crime trials, where prosecutors and judges continue to assert that there is a clear causal link between war propaganda, nationalism, and mass violence. Although most legal judgments hinge on the criminal intent of propagandists, the question of whether and to what extent propaganda and nationalism interact to cause support for violence or participation remains unanswered. Our goal here is to contribute to research on propaganda and nationalism by bridging international criminal law and the behavioral and brain sciences. We develop an experiment conducted with Serbian participants that examines the effects of propaganda as identified in the latest international speech crime trial as causing mass violence, and thereby test hypotheses of expert witness Anthony Oberschall’s theory of mass manipulation. Using principal components analysis and Bayesian regression, we examine the effects of propaganda exposure and prior levels of nationalism as well as other demographics on support for violence, ingroup empathy, and outgroup empathy. Results show that while exposure to war propaganda does not increase justifications of violence, specific types of war propaganda increase ingroup empathy and decrease outgroup empathy. Further, although nationalism by itself is not significant for justifying violence, the interaction of increased nationalism and exposure to violent media is significant for altering group empathies. The implications of these findings are discussed with respect to international criminal law and the cognitive science of nationalism.

战争宣传与民族主义之间的关系是什么，它们各自对支持或参与暴力行为的影响是什么？对于国际刑法和正在进行的言语犯罪审判，这是一个重要问题，检察官和法官继续断言，战争宣传，民族主义和大规模暴力之间存在明显的因果关系。尽管大多数法律判决取决于宣传者的犯罪意图，但宣传与民族主义是否相互作用以及在何种程度上相互作用以引起对暴力或参与的支持，这一问题仍未得到解答。我们的目标是通过将国际刑法与行为科学和脑科学联系起来，为宣传和民族主义研究做出贡献。我们开发了一项与塞尔维亚参与者进行的实验，该实验检查了最新的国际言语犯罪审判中确定的引起大规模暴力的宣传效果，从而检验了专家证人Anthony Oberschall的大规模操纵理论的假说。使用主成分分析和贝叶斯回归，我们研究了宣传暴露和民族主义先前水平以及其他人口统计学对暴力，群体内共情和群体外共情的支持的影响。结果表明，尽管暴露于战争宣传中并不能增加暴力的正当性，但特定类型的战争宣传会增加团体内共情，减少团体外共情。此外，尽管民族主义本身对于证明暴力合理性并不重要，民族主义与暴力媒体接触的互动对于改变群体同理心具有重要意义。这些发现的含义将在国际刑法和民族主义的认知科学方面进行讨论。