The Hawthorne studies--a fable for our times?

‘The consumer of knowledge can never know what a dicky thing knowledge is until he has tried to produce it’. F.J. Roethlisberger, investigator at Hawthorne There is a familiar anecdote that relates, with variations, that experiments with improved factory lighting increased the productivity of workers. The outcome seemed clear until someone turned the lighting down to below baseline, whereupon output increased still further. The moral of this tale, referred to as the Hawthorne effect, is that people change their behaviour when they think you are watching it. The story relates to the first of many experiments performed at the Hawthorne works of the Western Electric Company in Chicago from November 1924 onwards. The original aim was to test claims that brighter lighting increased productivity, but uncontrolled studies proved uninterpretable. The workers were therefore divided into matched control and test groups and, to the surprise of the investigators, productivity rose equally in both. In the next experiment, lighting was reduced progressively for the test group until, at 1.4 foot-candles, they protested that they could not see what they were doing. Until then the productivity of both groups had once again risen in parallel. Two volunteers went on to demonstrate that a high output was possible at 0.06 foot-candles, equivalent to moonlight. The investigators next changed the light bulbs daily in the sight of the workers, telling them that the new bulbs were brighter. The women commented favourably on the change and increased their work-rate, even though the new bulbs were identical to those that had been removed. This and other manoeuvres showed beyond doubt that productivity related to what the subjects believed, and not to objective changes in their circumstances. These at least seem to be the main facts behind the popular legend, although these particular experiments were never written up, …