By Douglas Fischer for The Daily Climate

Starting in 1924, a series of experiments on illumination and other workplace changes began in the Western Electric Co.'s mammoth Hawthorne plant outside of Chicago. By making small changes in factory lighting and on the assembly line and then observing the workers, researchers saw productivity increase. 

Only later did researchers realize that the act of observing the workers triggered those behavior changes – an experimental flaw now known as the "Hawthorne effect" and that remains a fundamental concern in any study assessing programs designed to alter human behavior.

The Hawthorne effect can be a decisive factor in any study trying to assess energy awareness and electricity consumption, scientists at Carnegie Mellon University reported on Monday.

Big gains with just a postcard

In their experiment, consumers received five postcards notifying and then reminding them of their participation in a study of household electricity use. The "experiment," participants were told, had a sole goal of measuring electricity consumption, would last one month and require no action on their part. A control group of households received nothing.

The result was that the households receiving a postcard reduced monthly electric use by 2.7 percent on average – a greater amount, the researchers note, than the annual conservation goal mandated by any state. 

The gains vanished after the study finished.

The research was led by Daniel Schwartz, then a graduate student at the Department of Social and Decision Sciences at Carnegie Mellon and who is now a post-doctoral researcher at the University of Pennsylvania's Wharton Risk Center. It was published in the journal Proceedings of the National Academy of Sciences.

A 'Hawthorne strategy?'

Schwartz and his colleagues concluded that the Hawthorne effect can be a potent influence on efforts to assess energy consumption. On the plus side, however, simple awareness can clearly be enough to prompt change.

"If awareness alone can improve performance in contexts where people require no additional information," the researchers wrote, "we might retire the 'Hawthorne effect' in favor of a 'Hawthorne strategy' of reminding people about things that matter to them but can get neglected in the turmoil of everyday life."

The Daily Climate is an independent, foundation-funded news service that covers climate change. Find us on Twitter @TheDailyClimate or email editor Douglas Fischer at dfischer [at]

Related on MNN:

This story was originally written for The Daily Climate and was republished with permission here.