Le origini della Psicologia del Lavoro

Elton Mayo's Hawthorne Experiments

The Studies

The Hawthorne Studies (or experiments) were conducted from 1927 to 1932 at the Western Electric Hawthorne Works in Chicago, where Harvard Business School professor Elton Mayo examined productivity and work conditions.

The studies grew out of preliminary experiments at the plant from 1924 to 1927 on the effect of light on productivity. Those experiments showed no clear connection between productivity and the amount of illumination but researchers began to wonder what kind of changes would influence output.

Variables Affecting Productivity

Specifically, Mayo wanted to find out what effect fatigue and monotony had on job productivity and how to control them through such variables as rest breaks, work hours, temperature and humidity. In the process, he stumbled upon a principle of human motivation that would help to revolutionize the theory and practice of management.

Mayo took six women from the assembly line, segregated them from the rest of the factory and put them under the eye of a supervisor who was more a friendly observer than disciplinarian. Mayo made frequent changes in their working conditions, always discussing and explaining the changes in advance.

He changed the hours in the working week, the hours in the workday the number of rest breaks. the time of the lunch hour. Occasionally, he would return the women to their original, harder working conditions.

Relay Assembly

The investigators selected two girls for their second series of experiments and asked them to choose another four girls, thus making a small group of six. The group was employed in assembling telephone relays - a relay being a small but intricate mechanism composed of about forty separate parts which had to be assembled by the girls seated at a lone bench and dropped into a chute when completed.

The relays were mechanically counted as they slipped down the chute. It was intended that the basic rate of production should be noted at the start, and that subsequently changes would be introduced, the effectiveness of which would be measured by increased or decreased production of the relays.

Feedback mechanism

Through out the series of experiments, an observer sat with the girls in the workshop noting all that went on, keeping the girls informed about the experiment, asking for advice or information, and listening to their complaints.

The experiment began by introducing various changes, each of which was continued for a test period of four to twelve weeks. The results of these changes are as follows:

Conditions and results

Under normal conditions with a forty eight hour week, including Saturdays, and no rest pauses. The girls produced 2,400 relays a week each.

  • They were then put on piece-work for eight weeks.
  • Output went up
  • Two five minute rest pauses, morning and afternoon, were introduced for a period of five weeks.
  • Output went up once more
  • The rest pauses were lengthened to ten minutes each.
  • Output went up sharply.
  • Six five minute pauses were introduced, and the girls complained that their work rhythm was broken by the frequent pauses.
  • Output fell slightly
  • Return to the two rest pauses, the first with a hot meal supplied by the Company free of charge.
  • Output went up
  • The girls were dismissed at 4.30 p.m. instead of 5.00 p.m.
  • Output went up
  • They were dismissed at 4.00 p.m.
  • Output remained the same
  • Finally, all the improvements were taken away, and the girls went back to the physical conditions of the beginning of the experiment: work on Saturday, 48 hour week, no rest pauses, no piece work and no free meal. This state of affairs lasted for a period of 12 weeks.
  • Output was the highest ever recorded averaging 3000 relays a week.
  • Confused? Read on.

    What happened during the experiments

    What happened was that six individuals became a team and the team gave itself wholeheartedly and spontaneously to co-operation in the experiment. The consequence was that they felt themselves to be participating freely and without afterthought and were happy in the knowledge that they were working without coercion from above or limitation from below.

    They were themselves satisfied at the consequence for they felt that they were working under less pressure than ever before. In fact regular medical checks showed no signs of cumulative fatigue and absence from work declined by 80 per cent.

    It was noted too, that each girl had her own technique of putting the component parts of the relay together - sometimes she varied this technique in order to avoid monotony and it was found that the more intelligent the girl, the greater was the number of variations (similar to McClelland's research findings into achievement motivated people.)

    The experimental group had considerable freedom of movement. They were not pushed around or bossed by anyone. Under these conditions they developed an increased sense of responsibility and instead of discipline from higher authority being imposed, it came from within the group itself.