The Chicago Factory Where Workers Were Studied for Forty Years Without Their Knowing the Study Was the Point

The Hawthorne Works at Cicero — a working-class suburb on the western edge of Chicago, separated from the city limits by the elevated tracks of the Burlington and Quincy Railroad — was the largest single manufacturing plant in the world at its 1929 peak. It belonged to Western Electric, the manufacturing subsidiary of the AT&T Bell System telephone monopoly, and made approximately 95% of every telephone, switchboard, and electrical-network component installed in the American telephone system. It employed approximately 45,000 people, ran continuous three-shift production seven days a week, and occupied about 200 acres of factory floor under a single roof. Its workforce was substantially first-generation immigrant (Czech, Polish, Italian, Lithuanian) and substantially female on the relay-assembly lines that supplied the switchboard market.

The Hawthorne Works is best remembered for two specific historical contributions, neither of which were anticipated at the time. The first was a maritime-disaster connection: the Hawthorne Works company picnic of 24 July 1915 produced the trip on which the SS Eastland capsized at its Chicago River mooring, killing 844 of the company’s employees. The second was the Hawthorne Effect — the now-canonical principle in social-science methodology that the act of observing a subject substantially modifies the subject’s behaviour.

The illumination studies, 1924-1927

The first sustained Hawthorne research project began in November 1924, organised by the National Research Council in cooperation with Western Electric management, to determine the optimal light intensity for relay-assembly productivity. The substantive research question was whether higher light levels would increase the rate at which the female assembly-line workforce could complete their fine-motor electromechanical work.

The result, as the project ran from 1924 to 1927, was anomalous. Productivity rose when lighting was increased; productivity also rose when lighting was decreased; productivity rose when the experimental room was darker than the control room; productivity rose when the experimental room was redecorated, when the experimental workers were given rest breaks, when the breaks were removed, when free lunch was provided, when free lunch was removed. The experimental variable — light intensity — was uncorrelated with the productivity outcome.

The Western Electric research staff (working under research director Clair Turner) eventually concluded around 1927 that the productivity effect was attributable to something other than the experimental variable. The substantive cause appeared to be the workers’ awareness that they were being studied. When they were watched they worked harder. When the experimental setup changed in any direction they worked harder. The actual conditions of the experiment were almost irrelevant to the outcome.

The Harvard team

Western Electric brought in the Harvard Business School industrial-relations researcher Elton Mayo in 1927 to redesign the research program around the unexpected initial finding. Mayo’s team — including Fritz Roethlisberger and William Dickson, both of whom would publish the standard 1939 reference text on the Hawthorne research — ran a more elaborate sequence of experiments at Hawthorne over the following five years:

The Relay Assembly Test Room (1927-1932) studied a small group of female relay-assembly workers under continuous-observation conditions for five years, varying their work-day length, rest-break frequency, payment structure, supervision intensity, and physical environment. Productivity rose progressively over the five-year period regardless of the variables. The conclusion was that the workers’ perception of management’s interest in their welfare was the substantive productivity factor.

The Bank Wiring Observation Room (1931-1932) studied a small group of male telephone-equipment wirers under continuous-observation conditions to determine the social-psychological factors that limited their productivity. The substantive finding was that the wirers maintained an informal output norm — below the management-set quota — through a sustained system of social pressure (the binging practice, in which workers struck each other on the arm to enforce conformity to the informal norm) that no formal management intervention could modify.

The Interview Program (1928-1930) conducted approximately 21,000 individual employee interviews at Hawthorne, gathering detailed personal-biographical and work-attitudinal information about the entire workforce. The substantive finding was that the workers’ explanations of their own productivity, satisfaction, and disengagement were shaped by their immediate small-group social context rather than by formal management-policy variables.

What the studies actually found

The Hawthorne studies’ substantive empirical contribution to industrial sociology is contested by subsequent research. Stephen Jones’s 1992 statistical reanalysis of the surviving Hawthorne raw data found that the original Mayo conclusions were overstated: the productivity gains during the Relay Assembly Test Room study can be explained by a combination of selection effects (the experimental group’s members were selected for above-average baseline performance), learning effects (the experimental group accumulated direct production experience over the five years), and the economic-incentive effects (the experimental group’s pay structure was incrementally improved over the period in ways that the experimenters did not adequately control for).

The actual Hawthorne Effect as it has entered standard methodological vocabulary — that subjects under observation modify their behaviour from baseline — is a real but smaller effect than the original Mayo research suggested. It is nonetheless one of the foundational methodological concepts of modern social science.

What the studies did establish robustly was the existence of informal social organization within ostensibly Taylor-managed industrial workforces. The Bank Wiring Observation Room study in particular produced the first documentary evidence that working-class American industrial workers maintained sustained informal-collective regulation of their own productivity in ways that explicitly resisted management’s formal quota-setting. The substantive insight became foundational in subsequent industrial-relations and labour-sociology research; the post-WWII American labour movement’s intellectual self-understanding was shaped by the Hawthorne findings.

The fall

The Hawthorne Works employed approximately 45,000 people at its 1929 peak, dropped to approximately 14,000 by 1933 during the Depression, recovered to approximately 25,000 during the Second World War, and operated at progressively reduced scale through the postwar decades. The decline began in the late 1960s as AT&T’s manufacturing operations were reorganised and Western Electric’s centralised production model was abandoned in favour of distributed regional facilities.

Hawthorne closed in 1983. The site was demolished over the following decade. A small portion of the original Hawthorne Works survives — the central administrative building with its distinctive 1905 brick clock tower has been preserved as a community college (Morton College) and a small Hawthorne Works museum opened in 2002 on the former site. The 200-acre factory complex is now the Cicero Hawthorne Works shopping center.

The empirical legacy of the Hawthorne research is the body of subsequent industrial-sociology research it inaugurated. The methodological legacy — the recognition that the act of observation modifies the behaviour observed — is the foundational principle of modern experimental social science. The actual factory in which both legacies were generated is, in modern Chicago, a big-box-retail strip mall.