Turn up the lights, and the workers work harder. Turn them down again, and they work harder still. The “Hawthorne Effect” is named after Western Electric's titanic Hawthorne Works in Cicero near Chicago, where a series of productivity trials was carried out between 1924 and 1932. Led by Elton Mayo, a professor at Harvard Business School, they are among the most famous experiments in social science. Not every social scientist is impressed.
Richard Nisbett, a social psychologist at the University of Michigan, complained to The New York Times a decade ago about the study's fame, calling it a “glorified anecdote”. He had a point. Among managers, the study is generally held to demonstrate that people respond to change: whatever you do, output rises for a while, as long as you do something. Inside academia, “the Hawthorne Effect” refers to the idea that people work hard once you start experimenting on them. Both beliefs are surprising enough to be interesting, while nicely confirming the prejudices of those who hold them.
Interested psychologists have known for a while that all was not well with the study. The experimental room was smaller and quieter than the factory floor. Two workers were sacked and replaced during the study for talking and idling. Experimental conditions were changed on Sundays, so each surge in productivity coincided with a Monday. These were not controlled conditions in the modern sense.