Paying attention to people at work improves their performance — these were the findings of a study done at the Hawthorne works of the Western Electric Company in Illinois in the 1920s. Various attempts by the management to improve workers' conditions were made; they included changes in light, rest breaks, hours of work and systems of payment. Each of these changes resulted in an increase in productivity — and so did a return to the original conditions of work. The investigators concluded that the changes in the external environment had not influenced the workers' performance so much as their PERCEPTION that people were interested in them and their work. An example of SOCIAL FACILITATION.