Which factor significantly influences whether people will intervene in emergencies?

The number of people present during an emergency is a significant factor influencing whether individuals will intervene, primarily due to the bystander effect. This phenomenon illustrates that as the number of witnesses increases, the likelihood of any one person taking action decreases. When there are many people present, individuals often feel less personal responsibility, assuming that someone else will intervene. This diffusion of responsibility can lead to inaction, as people may wait for others to respond instead of acting themselves.

The perceived severity of the situation can influence intervention, but it doesn't account for the psychological dynamics at play when multiple witnesses are involved. Similarly, while the known history of individuals in the group may shape perceptions about the likelihood of intervention, it is not as broadly impactful as the presence of others. Timing, while potentially relevant, does not have the same direct influence on the likelihood of action as the social context created by the number of bystanders. Thus, the number of people present is a crucial aspect of social behavior in emergencies.