title: Effects of aggressive behaviour and group size on collective escape in an emergency: a test between a social identity model and deindividuation theory.
abstract: This study models escape behaviour in emergency situations and compares the ability of deindividuation and social identity-based explanations in particular to account for responses. According to deindividuation theory, the larger the group, the higher the degree of anonymity and the stronger antisocial responses such as competitiveness will be. Moreover, the competition for escape should be more severe, and the escape rate lowered, in a large group, regardless of whether participants have an aggressive option. A social identity model predicts that when group members have an option of aggressive behaviour, the salience of the aggressive norm in a larger group will be stronger than that in a smaller group. In contrast, when participants only have concessive option, the salience of the non-aggressive norm in a large group is expected to be stronger than that in a small group. The results of Study 1 supported the social identity model. Study 2 tested how participants responded to their norm. The social identity model suggests a more conscious and socially regulated process whereas deindividuation theory implies an unconscious or unregulated process. The results showed that what directly affects norm formation is the density of stimulus, that is, the amount of aggression received from others and of others' escape activity divided by group size. The results suggest the conscious process of the norm formation and support the social identity model.
authors.affiliation: Department of Civil Engineering, Kyushu Institute of Technology, Sensui-cho, Tobata-ku, Kitakyushu 804, Japan. kugihara@dhs.kyutech.ac.jp
authors.forename: N
authors.initials: N
authors.lastname: Kugihara
mesh_terms: D000374:Aggression / Q000523:psychology*; D000704:Analysis of Variance; D004630:Emergencies / Q000523:psychology*; D006127:Group Structure; D006801:Humans; D008960:Models, Psychological; D012933:Social Identification