Third parties tend to take an active role and intervene in interpersonal conflicts in public. Previous research has shown that the level of aggression of these interventions determines how they influence the conflict. No previous study has, however, systematically investigated whether the aggression of third-party interventions is influenced by the development of the conflict situation. The objective of this study is twofold. First, the study determines the extent to which the aggression level of intervening third parties changes during the course of interpersonal conflicts. Second, the study identifies and investigates the factors that affect the aggression levels displayed by intervening third parties. We systematically observed and coded CCTV footage of 46 interpersonal conflicts in public space, recorded by surveillance cameras in Amsterdam, the Netherlands. The data included 565 intervention behaviors by 125 third parties. We recorded the levels of aggression of the individuals involved in the conflict and conducted a multinomial logistic regression analysis to investigate what influenced the aggression level of the third-party interventions. We found that the aggression levels of the preceding intervention behaviors by the third parties predict aggression levels of their subsequent interventions. This shows a consistency in third-party interventions over the course of a conflict. We also found that the aggression levels of the conflict parties that are the targets of the interventions influence the aggression levels of third-party intervention. This finding demonstrates that the development of the conflict situation influences how aggressive the third parties are. Our study emphasizes the importance of taking the interactional dynamics of interpersonal conflicts into consideration when explaining third-party behavior.

第三方倾向于在公共场合扮演积极角色并介入人际冲突。先前的研究表明，这些干预措施的侵略程度决定了它们如何影响冲突。然而，之前的研究没有系统地调查第三方干预的侵略是否受到冲突局势发展的影响。这项研究的目的是双重的。首先，该研究确定了人际冲突过程中干预第三方的攻击性水平变化的程度。其次，该研究确定并调查了影响第三方介入的侵略程度的因素。我们系统地观察并编码了 46 起公共场所人际冲突的闭路电视录像，这些录像由阿姆斯特丹的监控摄像头记录下来，荷兰人。数据包括125个第三方的565个干预行为。我们记录了冲突中个人的攻击性水平，并进行了多项逻辑回归分析，以调查影响第三方干预攻击性水平的因素。我们发现，第三方先前干预行为的攻击性水平预示着他们后续干预行为的攻击性水平。这表明在冲突过程中第三方干预的一致性。我们还发现，作为干预目标的冲突各方的侵略程度会影响第三方干预的侵略程度。这一发现表明，冲突局势的发展会影响第三方的攻击性。