Final answer:
The presence of many bystanders usually results in a decreased likelihood of individual intervention in emergencies because of the bystander effect and diffusion of responsibility.
Step-by-step explanation:
The presence of many bystanders at the scene of an emergency increases the likelihood that any individual bystander will fail to interpret the incident as an emergency, due to a psychological phenomenon known as the bystander effect. This effect is closely related to the concept of diffusion of responsibility, where individuals in a group feel less compelled to take action because they believe that someone else will do so. The bystander effect is influenced by various factors including the size of the group, anonymity, group cohesiveness, and the presence of other people perceived as competent to help.