 Hawthorne effect occurs when a participant's behavior changes as a result of being observed, rather than as a result of an intervention. In other words, when groups or individuals realize they are being observed, they may change their behavior. This change can be positive or negative, depending on the research context. The first study that identified the Hawthorne effect observed that increased lighting increased worker productivity. Later, it was concluded that increased productivity was due to the worker's response to the increased attention from supervisors, not to the changes in working conditions. This came to be known as the Hawthorne effect.