This is the official account of the experiments carried out at the Hawthorne Works of the Eastern Electric Company in Chicago. These were divided into test room studies, interviewing studies and observational studies. The test room studies were experiments into what variables in a workplace environment might affect worker fatigue. The findings of these tests led to extensive interviewing on the attitudes of the workers. The final phase of the Hawthorne experiment focused on social factors, using techniques of cultural anthropology to observe small working groups. The results of these experiments profoundly influenced the Human Relations movement.