In the 1920s, in order to understand the relationship between productivity and job satisfaction, Harvard Business School professor Elton Mayo and research assistant (and later HBS professor) Fritz J. Roethlisberger studied worker behavior at Western Electric’s Hawthorne Works plant outside Chicago. Over a five-year period, they tracked the performance of six women assembling relays in a room separate from the main assembly hall. The workers’ productivity rose, which led Mayo to conclude: “The six individuals became a team.”

From 1928 through 1930, Mayo and Roethlisberger helped conduct 21,000 interviews at the plant and found that mental attitude, proper supervision, and informal social relationships were critical to boosting productivity and job satisfaction. However, in 1966, Roethlisberger and William Dickson, a supervisor at Hawthorne, revisited the data and published a book entitled Counseling in an Organization, in which they argued that subjects change their behavior when observed. They called that phenomenon the Hawthorne Effect. Other academics have drawn different conclusions from the data, but all of them agree that the Hawthorne experiments laid the foundation for the field of organizational behavior.