In the 1920s and 1930s a series of workplace experiments were undertaken at the Hawthorne Works, a factory owned by Western Electric outside of Chicago. The purpose of the experiments was to determine what factors would boost worker productivity. The research was led by Elton Mayo of Harvard.

The first experiment boosted the brightness of the lights for an experimental set of workers but kept the lights the same for the control group. The finding? Productivity increased for the group with the brighter lights. Other experiments included lengthening work breaks, making work breaks shorter but more frequent, changing the humidity and making work stations tidier. The results? When each condition changed, productivity soared. Then, the work conditions were returned to the initial conditions, dimmer lights, original break structure, etc and the researchers found that productivity hit an all-time high. Thus, the main finding at Hawthorne was that regardless of the experimental variable manipulated, worker productivity improved.

The phenomenon observed in the study, now dubbed “The Hawthorne Effect”, is that subjects in behavioral studies often change their performance in response to being observed. Some general conclusions that can be drawn from the Hawthorne Effect:

• The performance of a worker is not just dependent on his/her individual attributes. The environment in which they work matters. If they received attention and felt like management cared about them productivity was improved.

• The social aspects of the work environment matter. In some of the Hawthorne experiments groups of workers were moved into small working groups for study. From an HBS write up of the Hawthorne studies: “The women noted that the intimate atmosphere of the test room gave them a sense of freedom not experienced on the factory floor. They felt more at ease to talk and over time developed strong friendships. ‘We’ve been the best friends since the day we were in the test room,’ one of the operators remembered. ‘We were a congenial bunch.’ Through the years, productivity in the relay assembly test room rose significantly. [The lead researcher] reasoned that ‘the six individuals became a team and the team gave itself wholeheartedly and spontaneously to co-operation in an experiment.'” Thus, working in a team can greatly impact performance.

• Beware seeing cause and effect where it doesn’t actually exist. If the Hawthorne researchers had merely boosted the lighting and stopped there they would have concluded that lighting boosts productivity. Only after dimming the lights again and finding that productivity was also boosted did they realize that something else was going on and that cause and effect didn’t lie with the lighting. Note that some subsequent studies have not found that a Hawthorne effect exists and that probably the strongest lesson from the Hawthorne experiments is to be wary of seeing cause and effect just because certain variables are changed.

The experiments at the Hawthorne plant, according to Scientific American, “led to a radical change in thinking about management, giving birth to a new school of human relations in management that still shapes theory and the way many of us work.”