Since the September 11, 2001 terrorist attack against the World Trade Center in New York City, terrorism has become one of the most distressing large‐scale societal threats. The March 22, 2016 terrorist attack in Brussels, the capital of Belgium undermined the collective sense of perceived security and social cohesion. The present research investigates Belgian civilians’ (N = 202) terrorist threat perception, personal emotions, and the role of perceived emotional synchrony in the construction of the perceived socioemotional climate in Belgium. The main purpose of the current study was to examine the role of perceived emotional synchrony emerging in collective gatherings as a regulatory mechanism improving the perceived socioemotional climate of the country. Additionally, the precise components (personal vs. collective) shaping the perceptions of terrorist threat were also examined. This study was conducted by a questionnaire during the collective gatherings in Brussels 1 week after the terrorist attack. The main results suggest that the terrorist threat has been perceived at the collective level rather than at the personal level. Furthermore, the perceived emotional synchrony with others mediated specifically the relationship between positive personal emotions and the perceived positive socioemotional climate in Belgium. Such findings point to the importance of considering the perceived emotional synchrony in order to provide a better understanding of lay people's psychosocial responses to terrorism and the subsequent construction of collective macro‐social phenomena in post‐terrorist contexts.

Terrorism is one of the most frightful large-scale societal threats nowadays. The January 7, 2015 Charlie Hebdo terrorist attack in Paris shattered French's sense of security. The present research investigates French citizen's (N = 160) terrorist threat perception (personal vs. collective), behavioral changes, social sharing of emotions and perceived socioemotional climate using the social stage model of collective coping with disasters (Pennebaker & Harber, 1993). This study was conducted by a questionnaire at three points of time (i.e., one week, one month and two month) following the attack. The results suggest that terrorist threat perception has not decreased across time at the personal level nor at the collective level. However, the extent of social sharing of emotions and the positive socioemotional climate decreased from the initial emergency stage to the subsequent adaptation stage. Such findings point to the importance of taking temporality into account to provide better understanding of lay people's responses to terrorism.Keywords: Terrorism; threat perception; behavioral changes; social sharing of emotion; socioemotional climate Le terrorisme est l'une des menaces sociétales à grande échelle les plus effroyables de nos jours. L'attaque terroriste de Charlie Hebdo du 7 janvier 2015 à Paris a ébranlé le sentiment de sécurité des Français. La présente recherche examine la perception de la menace terroriste (personnelle vs. collective), les changements comportementaux, le partage social des émotions et le climat socio-émotionnel perçu auprès des citoyens français (N = 160) en se basant sur le modèle des étapes sociales de coping collectif avec les catastrophes (Pennebaker & Harber, 1993). Cette étude a été conduite par questionnaire à trois points temporels (c.-à-d., une semaine, un mois et deux mois) après l'attaque. Les résultats suggèrent que la perception de la menace terroriste n'a pas diminué à travers le temps, ni au niveau personnel, ni au niveau collectif. Toutefois, l'ampleur du partage social des émotions et du climat socio-émotionnel positif perçu a diminué entre la phase initiale d'urgence et la phase ultérieur d'adaptation. Ces résultats soulignent l'importance de la prise en compte de la temporalité pour une meilleure compréhension des réponses des personnes au terrorisme.

Rumours are an ubiquitous feature of people's social life and one of the oldest topics in social psychology. Rumours, which tend to spread during crisis situations, allow people to mitigate unpleasant feelings and construct a meaning of the surrounding world. Rumour transmission has been associated with a number of specific individual (e.g., anxiety, personal involvement) and situational (e.g., ambiguity, uncertainty) characteristics and studied with the serial reproduction paradigm (Allport & Postman, 1947) in laboratory settings. The main criticism of rumour research has been its focus on primarily individual-level analyses in an attempt to explain a social phenomenon. Furthermore, the classic serial reproduction paradigm tends to omit the essential properties of interpersonal interactions and communication processes. Despite the recent and rapidly growing trend of social network methods in social and behavioural sciences, rumour research could also include a finer analysis of individuals' social characteristics and the related complexity of real-life communication processes.Therefore, the integration of a socially situated approach to rumour transmission might be especially relevant for rumour research and promising for the study of other social phenomena by extension.Rumours are a pervasive feature of people's social life. All people have been confronted by idle conversation in their surroundings that was later revealed to be largely or even completely false. Such inexact or false hearsay can relate to daily concerns or major societal issues. Rumours about the supposed perpetrators of the September 11, 2001 terrorist attacks on the World Trade Center in New York City spread throughout the world within a few hours of the