The Hawthorne Effect: What It Is and Whether It Holds Up
The Hawthorne effect is the tendency of people to change their behavior when they know they are being observed, a claim later reviews have made much less certain.
The Hawthorne effect is the tendency of people to change their behavior when they know they are being watched or studied. The name comes from a series of factory studies at the Hawthorne Works, a Western Electric plant in Cicero, outside Chicago, in the 1920s and early 1930s. The original reading was that workers became more productive whatever researchers changed, simply because they were being attended to. Later reviews have found that claim much less certain.
What happened at the Hawthorne Works?
From about 1924, researchers studied how working conditions affected output. Early illumination experiments tested whether brighter or dimmer lights changed productivity. Later, in a relay assembly test room, a small group of women assembled telephone relays while the team varied rest breaks, the length of the working day and other conditions, and recorded their output.
Output tended to rise with each change, and it kept rising in some periods when conditions were returned to the original. The researchers' explanation centered on attention and social factors: the workers felt consulted and part of a team. Elton Mayo, a Harvard researcher later associated with the studies, promoted this human-relations reading. A later report stressed the informal groups among the workers and their relations with supervisors. The studies ran for years and included a large interview program, in which workers were asked about their jobs and their supervisors.
Where did the name come from?
The label came later. In 1958 the sociologist Henry Landsberger reviewed the studies and named the pattern the Hawthorne effect. His reading treated the observation itself as the cause of the change in behavior. Landsberger's point was partly methodological. Any study that watches people has to allow for the watching, so the label named a problem for researchers as much as a finding about workers.
Did the effect hold up?
Critics have argued that the original records are incomplete and that the changes in output had other causes, such as shifts in supervision, pay incentives and the workers' own choices. In 2011, two economists, John List and Steven Levitt, re-examined the illumination experiments and concluded that the original data give little support to the effect as first described. Another objection is that the test room held a small, unusual group, watched closely over a long period, which makes its results hard to generalize to a whole factory.
What else changes when people are watched?
Observation changes behavior in many settings, so the idea remains useful. Drivers slow down near speed cameras, and hospital staff wash their hands more often when they know their hygiene is being observed.
Participants in psychology experiments may also guess what the researcher wants and act to fit, a pattern called demand characteristics. The general effect is real in many settings. What is contested is the factory claim, that output rose simply because someone was watching. Researchers often describe these patterns as reactivity, the general tendency of a thing that is measured to change while it is being measured.
Why does it matter for research?
The idea matters most in experiment design. A study can produce a result because of the attention itself rather than the treatment being tested. Researchers guard against this with control groups that receive the same attention, and with blinding, where participants and staff do not know who receives the real intervention. The same care applies in medicine. Patients in a treatment arm and patients in a control arm should receive the same visits, questionnaires and reminders, so that any difference can be traced to the treatment rather than to the attention. Checking whether an effect is real therefore means comparing against a control group, not only looking at results before and after a change.
This is the same logic as the placebo effect, in which expectation changes results. For the wider method of testing claims against controls, see the scientific method. Group settings bring their own pressures as well, as in social loafing, where individuals put in less effort when their contribution is hard to see.
Tags
behavior cognitive biases experiments psychology social psychology
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