I have heard about a few terrible crimes that happened on trains recently, in the U.S. and Japan. In each of these incidents (事件), a person was attacked on a train. And even though there were many other people on the train, they only watched. They didn't help the person who was being attacked.
My major （専門）in university was psychology (心理学）. We studied this phenomenon (現象). We learned that when one person sees another person having trouble, and there are few other people around, the responsibility (責任）to help that person becomes heavier (重くなる）. But if there are many other people around, the responsibility is shared by all the people. So each person's weight of responsibilty (責任の重さ) is light (軽い) or diluted (薄めてる) because it's shared with lots of other people.
When there are many people who see a person being attacked, they feel less pressure to help, and they wait to see if someone else can do it. Even if they feel very sorry for the person who is being attacked, they are also afraid to risk their own safety (自分の安全を懸ける）to help.
In one of my psychology classes, the professor decided to do an experiment on the class. Before class, she contacted the students who sat in the first 3 rows. She told us, "In class I will act strangely, as if I'm sick. Please don't try to help me. I am only pretending." (pretend = 見せかける)
I sat in the second row. I thought it was a strange request, but of course I agreed to do what my professor asked.
When it was time for class, we began as usual. The professor was standing at the front of the room, and we students sat at our desks. There were many students in this class.
The professor began her lecture, but soon she began to act like she was feeling bad. She stumbled (よろける? 躓く?) and dropped all her papers on the floor, and she made sounds as if she was feeling sick.
We students sitting in the first 3 rows felt a little nervous, but the professor had told us that she would do this, and she told us not to help her--that she was only pretending to be in trouble. So we students in the front sat still. We could feel the atmosphere in the room change. Students who were sitting in desks behind the third row were worried about the professor. But the people sitting in the front rows didn't help her. What should they do?
It seemed like a long time that no one did anything. Finally, two young women who sat in the very back row stood up and came to the front to help our professor. One picked up her papers, and the other held her arm to support her, and asked her, "Are you okay?"
At that point our professor stood up straight and told the students who came to the front to help her thank you. She told everyone that she was actually okay, that she was only pretending to feel sick. The two students went back to their desks, and the professor then gave us a lecture about how we feel responsibility to help a person in trouble if there are many people around. Especially if the people nearest (近い人) the trouble don't help, it takes a long time for the people who are farther away (離れてる人) to decide to help.
Have you ever been in a situation where you saw someone in trouble? Did you help?