Final answer:
The phenomenon of people not helping someone they do not know is often attributed to the b. bystander effect and diffusion of responsibility, which are social psychological concepts explaining why individuals in groups may fail to act in emergencies.
Step-by-step explanation:
Some social psychologists attribute the phenomenon of people not helping someone they do not know to two processes: the bystander effect and the diffusion of responsibility. The bystander effect occurs when witnesses or bystanders are less likely to help a victim or person in distress when there are other people present. This is due to the diffusion of responsibility, which suggests that individuals in a group feel less compelled to act because they believe someone else will step in. Social psychologists also explain that the likelihood of helping decreases as the number of bystanders increases due to this shared sense of responsibility. For instance, during the tragic case of Kitty Genovese, the responsibility to call the police was diffused among the witnesses, leading to a delay in helping her. It is this social phenomenon that can lead to inaction in emergencies.