The bystande affect

So a while ago I made a post comparing the scene of the woman getting beat in psycho pass to an audio i heard of a woman telling people to help a man who's like getting beat by ice or something. I just said that people are so desensitized to media in America because we're used to seeing or hearing about so much violence and psycho pass its the opposite,they actually aren't used to seeing such violence because the media is likely extremely restricted. But yea I didn't know the name for it and now I do. Apparently its where yoy expect someone else to do something in serious situations