Book Definition: Dilution or weakening of each group member's obligation to act when responsibility is perceived to be shared with all group members.
As group size increases, because each person assumes the others will help, they do not intervene or make any commitments to the situation.

History (Optional)

The Thirty Who Saw Murder ~ Kitty Genovese case

In Your Own Words

  • Believing that, since there are more people involved, rather than just yourself, someone else in the group will help the person out.
  • When a bad situation arises, individual morals and sense of responsibility decreases in the individual as group size increases.
  • Thinking that you don't have to put as much effort into something because there are multiple minds involved in the thinking process.
  • Thinking that someone else will do what is necessary.
  • "Oh, he'll do it."
  • Personal responsibility to act in a situation is decreased in large groups.
  • leads to social loafing


  • Driving past a disabled car and automatically thinking "Oh, well there are a lot of other people on the road, I'm sure one of them will help out."
  • Kitty Genovese was murdered and raped in front of 38 people. None of the people acted because they all thought that someone else would call.
  • Not raising your hand to answer a question in class because you figure there are others who can also answer the question.
  • People not picking up trash in the cafeteria because they figure someone else will do it for them.
  • Seeing a person passed out on the sidewalk and thinking that one of the other hundreds of people around who has more time will help out
  • Not helping out or doing your part in a group project because you figured another group member would do it anyways
  • Seeing someone drop all their boks/paper in the hallway and not bothering to help them because you think that there are tons of people in the hallway and that one of them is bound to help out.
  • Seeing an older woman struggling to carry all her bags out of the grocery store, and not helping her because there are plently of people around her that will probably help her out.

Additional Resources