Answer:
the bystander effect
Step-by-step explanation:
The bystander effect is a psychological claim where the presence of other people in an emergency situations prevents or discourages any individual to offer help to the victims. It can be seen that more the number of bystander,it is less likely that one of the people will help.
Thus in the context, according to the law enforcement, it is always advisable in emergency situation to pick up any stranger individual from the crowd and request him offer assistance rather than crying for help to the group. Thus this would defeat the bystander effect.