The bystander effect refers to the phenomenon in which the greater the number of people present, the less likely people are to help a person in distress.
There are countless examples of the bystander effect. You can probably remember some situations where you have seen it firsthand. Would you be more likely to help an elderly woman if she fell in a very crowded area, or if you were the only one around? If you saw a couple fighting aggressively and it looked like someone was going to get hurt, would you be more likely to interfere at a crowded party or at a small gathering?
The bystander effect happens because people assume that in a situation where many others are present, someone else will attend to an emergency. We feel less responsibility and duty when we feel that there is probably someone more competent or assertive nearby. The bystander effect is a big problem. To look at 10 horrifying and true cases in which the bystander effect took place, take a look at this website:
http://listverse.com/2009/11/02/10-notorious-cases-of-the-bystander-effect/
What can be done? First and foremost, always assume responsibility in cases of crisis. Easier said than done, I know, but you must keep this in your mind. Action in emergencies must be the norm. Be the first to break the silence. If you see something happening and you feel it is wrong, speak. Act. You could save someone’s life.