Listen to part of a lecture in a psychology class.
(man) Now a study was done that illustrated this phenomenon. In the study people were given an ordinary task that everyone has probably done before. They were simply asked to peel potatoes, and to peel as many potatoes as possible in a given amount of time. Ok so, some people worked alone, and they were told that the number of potatoes they each peeled would be recorded. Others peeled potatoes together, as part of a group, and they were told that only the total number of potatoes peeled would be recorded. So it would be impossible to tell how many any one person had done.Then researchers compared the results of people who worked alone and those who worked together to see if there was any difference. That is, they took the average score of the people working alone and compared it to the average score of the people working together in a group, and they did discover a difference! It turns out that people working in a group peeled significantly fewer potatoes that people who worked alone.