A series of investigations carried out at the Hawthorne plant of the Western Electric Company in Illinois between 1927 and 1932, under the direction of Elton Mayo, which marked a turning point in the history of industrial psychology. The scale of the research was vast – in one phase over 20,000 employees were interviewed – and it explored various aspects of the way in which the employees regarded their work, their colleagues and their supervisors. Apart from the Hawthorne effect, one other major finding that attracted great attention was that a work group could set its own rate of production regardless of external financial incentives offered by management to the group or to the individuals in it.