Eiton Mayo, a professor at Harvard, once did a five-year study at the Western Electric Hawthorne Works in Chicago to find out what effect fatigue and monotony had on productivity. He stumbled onto a motivation principle that revolutionized the theory and practice of management. Mayo took five workers off the assembly line and put them under the watchful eye of a friendly supervisor. Then he started to make frequent changes in their work conditions. But he always discussed the changes in advance. He changed their work hours, number of breaks, and lunch times. Occasionally, he would switch back to the original, more difficult working conditions. To his surprise, changing back to the tougher conditions didn't adversely affect production. Instead, it kept going up. The professor realized that by singling out certain workers, he raised their self-esteem. They developed a friendly relationship with the supervisor and soon began to feel more like part of a team. Exercising a freedom they never had before, the workers talked, joked, and began meeting socially after work. Mayo and the supervisor had their cooperation and loyalty. That explained why production levels rose even when rest breaks were taken away. The part of the study dwelling on positive effects of benign supervision and the effort to make workers feel like they're part of a team became known as the Hawthorne Effect. We still see this used in management today.