It is unclear how building occupants use information about the social and built environment when choosing an egress route during emergency evacuation. Conflicting tendencies have been previously reported: to follow the crowd, to avoid congestion, and to avoid unknown egress routes alone. We hypothesize that these tendencies depend on an interaction between social influence and the affordances (opportunities for egress) of the built environment. In three virtual reality (VR) experiments (each $N=15$), we investigated how social influence interacts with the affordances of available exits to determine exit choice. Participants were immersed in a crowd of virtual humans walking to the left or right exit and were asked to walk to one of the exits. Experiment 1 tested the role of social influence by manipulating both the proportion of the crowd walking toward one exit point (Crowd Proportion of 0 to 100%, in 10% increments) and the absolute number of virtual humans going to the exit point (Crowd Size of 10 or 20). Experiment 2 tested the role of affordances by introducing two visible exit doors (1 m width) in a closed room, and following the same protocol. Experiment 3 tested larger exit doors (2 m width) that afford rapid egress for more people. In the small crowd, participants were increasingly likely to follow the majority as its proportion increased. In the large crowd, however, participants tended to avoid the more crowded exit if the doors were narrow (Experiment 2), but not if the doors were wide (Experiment 3). Participants tended to follow a 100% majority in all experiments, thereby avoiding going to an exit alone. We propose that the dynamics of exit choice can be understood in terms of competition between alternative egress routes: the attraction of an exit increases with the proportion of the crowd moving toward it, becoming dominant at 100%, but decreases with the absolute number in the crowd moving toward it, relative to the exit’s affordance for egress.

目前尚不清楚建筑物居住者在紧急疏散期间选择出口路线时如何使用有关社会和建筑环境的信息。以前曾报道过相互冲突的趋势：跟随人群，避免拥堵，以及单独避开未知的出口路线。我们假设这些趋势取决于社会影响和建筑环境的可供性（出口机会）之间的相互作用。在三个虚拟现实 (VR) 实验中（每个$ñ=15$），我们研究了社会影响如何与可用出口的可供性相互作用以确定出口选择。参与者沉浸在一群向左或向右出口的虚拟人中，并被要求步行到其中一个出口。实验 1 通过操纵走向一个出口点的人群比例（0 到 100% 的人群比例，以 10% 递增）和前往出口点的虚拟人的绝对数量（人群规模）来测试社会影响的作用10 或 20)。实验 2 通过在封闭的房间中引入两个可见的出口门（1 m 宽）并遵循相同的协议来测试可供性的作用。实验 3 测试了更大的出口门（2 m 宽），可以为更多人提供快速出口。在小小的人群中，随着大多数人的比例增加，参与者越来越有可能追随大多数人。然而，在人群众多的情况下，如果门很窄（实验 2），参与者倾向于避开更拥挤的出口，但如果门很宽（实验 3）则不会。参与者倾向于在所有实验中遵循 100% 的多数，从而避免独自离开。我们建议出口选择的动态可以通过替代出口路线之间的竞争来理解：出口的吸引力随着出口的增加而增加。向它移动的人群比例，在 100% 时占主导地位，但相对于出口的出口可供性，随着向它移动的人群中的绝对数量而减少。