Significance A large-scale survey of pilgrims on the Hajj to Mecca (also called Makkah) showed that where there is identification with the crowd the negative effect of crowd density on safety is diminished or even reversed: a new finding. The reason that identification with the crowd moderates the effect of density on safety is because crowd identification increases the perception that others will be supportive. This process also helps to explain national differences among pilgrims in feelings of safety during the event. In contrast both to engineering approaches, which neglect crowd psychology, and traditional crowd psychology, which assumes that the crowd is inherently a “problem,” this study shows how the crowd can be part of the solution in crowd safety management.

Around 2 million pilgrims attend the annual Hajj to Mecca and the holy places, which are subject to dense crowding. Both architecture and psychology can be part of disaster risk reduction in relation to crowding, since both can affect the nature of collective behaviour-particularly cooperation-among pilgrims. To date, collective behaviour at the Hajj has not been systematically investigated from a psychological perspective. We examined determinants of cooperation in the Grand Mosque and plaza during the pilgrimage. A questionnaire survey of 1194 pilgrims found that the Mosque was perceived by pilgrims as one of the most crowded ritual locations. Being in the plaza (compared with the Mosque) predicted the extent of cooperation, though crowd density did not. Shared social identity with the crowd explained more of the variance than both location and density. We examined some of the process underlying cooperation. The link between shared social identity and giving support to others was stronger in the plaza than in the Mosque, and suggests the role of place and space in modulating processes of cooperation in crowds. These findings have implications for disaster risk reduction and for applications such as computer simulations of crowds in pilgrimage locations.This article is part of the theme issue 'Interdisciplinary approaches for uncovering the impacts of architecture on collective behaviour'.

Previous research has shown that participation in the Hajj pilgrimage to Mecca can lead to both more positive outgroup attitudes and increased commitment to Muslim identity. We describe a survey of pilgrims (N = 1,176) carried out at Mecca, during the Hajj, which tested explanations for these experiences of self‐change at the time of their occurrence. In line with contact theory, perceived cooperation among pilgrims indirectly predicted more positive outgroup attitudes (as well as enhanced Muslim identification), via identification with the crowd. In line with social identity and identity congruence explanations, positive emotional experience and the perception that the crowd embodied the Muslim value of unity predicted self‐change variables through identification with the crowd. The finding that participation in an all‐Muslim gathering increases positive views of other groups (including non‐Muslims) through identification with the crowd offers an alternative perspective to suggestions that such gatherings might encourage intolerance.

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