It turned out that the workers seemed to be responding more to the attention they were receiving from management than to any physical change in their environment. With each change, the workers suspected (consciously or unconsciously) they were being observed and therefore worked harder.
This phenomenon came to be known as the Hawthorne Effect. It states that the very fact that people are under study, observation or investigation can have an effect on them and the results.
[Read more…] about Latticework of Mental Models: Hawthorne Effect