Motivational changes due to individual differences and situational variations in ingroup identification can influence accessibility of memories of ingroup violence, victimization and glories. In Study 1, high identifiers recalled fewer incidents of ingroup violence and hatred than of ingroup suffering. As well, they recalled fewer incidents of ingroup violence and hatred than did low identifiers. In Study 2, a manipulation of ingroup identity produced shifts in memory. Relative to those in the low identity condition, participants in the high identity condition recalled fewer incidents of violence and hatred and more good deeds by members of their group. Participants in a control condition recalled more positive than negative group actions; this bias was exaggerated in the high identity condition and eliminated in the low identity condition. With respect to memories of ingroup tragedies, Studies 3 and 4 demonstrated that experimental reminders of ingroup suffering enhanced participants' sense of connectedness to the ingroup. The findings suggest that memories of ingroup aggressions threaten ingroup identity whereas memories of ingroup suffering enhance ingroup identity. Societal implications of the findings are discussed. The present research informs the literature on reconstructive memory by extending previous findings on the flexibility of personal memories to historical memory.

Motivational changes due to individual differences and situational variations in ingroup identification can influence accessibility of memories of ingroup violence, victimization and glories. In Study 1, high identifiers recalled fewer incidents of ingroup violence and hatred than of ingroup suffering. As well, they recalled fewer incidents of ingroup violence and hatred than did low identifiers. In Study 2, a manipulation of ingroup identity produced shifts in memory. Relative to those in the low identity condition, participants in the high identity condition recalled fewer incidents of violence and hatred and more good deeds by members of their group. Participants in a control condition recalled more positive than negative group actions; this bias was exaggerated in the high identity condition and eliminated in the low identity condition. With respect to memories of ingroup tragedies, Studies 3 and 4 demonstrated that experimental reminders of ingroup suffering enhanced participants' sense of connectedness to the ingroup. The findings suggest that memories of ingroup aggressions threaten ingroup identity whereas memories of ingroup suffering enhance ingroup identity. Societal implications of the findings are discussed. The present research informs the literature on reconstructive memory by extending previous findings on the flexibility of personal memories to historical memory.

Ce mémoire vise à mettre en lumière les raisons pour lesquelles de nombreux épisodes de comportement collectif violents se sont produits dans les contiones au cours du dernier siècle de la République romaine (133-44 av. notre ère). Pour y parvenir, nous avons fait appel à un cadre d’analyse spécialisé dans la compréhension des conflits intergroupes et utilisé depuis peu par les historiens : la psychologie sociale. Nous avons particulièrement employé la théorie de l’identité sociale parce qu’elle est considérée comme étant la plus complète pour expliquer les comportements intergroupes à l’échelle d’une société autant qu’à celle d’une foule. Il se trouve que l’apparition de la violence dans les contiones s’explique à la fois par des raisons liées au contexte politique, social et économique de la société romaine des deux premiers siècles av. notre ère que par des facteurs propres à ce type d’assemblée. En s’inspirant d’études récentes, notre analyse a commencé par montrer que le contexte politique et économique de Rome a provoqué des divisions entre les groupes qui la constituaient. En considérant cette fragmentation, nous avons pu reconnaître la présence de facteurs favorisant les conflits intergroupes à l’échelle macro. Nous avons ensuite étudié séparément les deux traits distinctifs des contiones (un public s’assemblait et un orateur discourait) afin de déterminer en quoi ils ont contribué à ce que des débordements violents surviennent. Notre analyse nous a permis d’avancer que les contiones étaient l’un des rares contextes dans lesquels les individus rassemblés classaient leurs pairs en fonction de leur appartenance à un groupe politique et où un orateur pouvait influencer les dynamiques qui se développaient entre ces groupes. Étant donné la situation troublée dans laquelle la société romaine se trouvait, les contiones constituaient un environnement propice à l’éclatement de conflits intergroupes. / This master’s thesis aims to shed light on why many episodes of violent collective behavior occurred in the contiones during the last century of the Roman Republic (133-44 BC). To get there, we have drawn on an analytical framework specialized in the understanding of intergroup conflict and recently used by historians: social psychology. We mainly used the Social Identity Theory because it is considered the most comprehensive in explaining intergroup behavior at both the societal and crowd levels. It turns out that the appearance of violence in the contiones can be explained both by reasons related to the political, social and economic context of Roman society in the first two centuries BC and by factors specific to this type of assembly. Drawing on recent studies, our analysis began by showing that the political and economic context of Rome caused divisions between the groups that constituted it. By considering this fragmentation, we were able to recognize the presence of factors that encouraged intergroup conflicts on a macro scale. We then looked separately at the two distinctive features of contiones (an audience assembled and a speaker discoursed) to determine how they contributed to violent outbursts. Our analysis suggested that contiones were one of the few contexts in which assembled individuals categorized their peers according to their political group membership and where a speaker could influence the dynamics that developed between these groups. Given the troubled state of Roman society, the contiones provided a fertile environment for intergroup conflict.