Hawtorne Effect
The Hawthorne effect
describes a temporary change to behavior or performance in response to a
change in the environmental conditions, with the response being
typically an improvement. The term was coined in 1955 by Henry A.
Landsberger when analyzing older experiments from 1924-1932 at the
Hawthorne Works (outside Chicago). Landsberger defined the Hawthorne
effect as:
Hawtorne effect is a
short-term improvement caused by observing worker performance.
Earlier researchers had concluded the short-term improvement was caused
by teamwork when workers saw themselves as part of a study group or
team. Others have broadened the definition to mean that people's
behavior and performance change following any new or increased
attention. Hence, the term Hawthorne effect no longer has a specific
definition.
The Hawthorne studies have had a dramatic effect on management in
organizations and how people react to different situations. Although
illumination research of workplace lighting formed the basis of the
Hawthorne effect, other changes such as maintaining clean work stations,
clearing floors of obstacles, and even relocating workstations resulted
in increased productivity for short periods of time. Thus the term is
used to identify any type of short-lived increase in productivity. In
short, people will be more productive when appreciated or when watched.
The term Hawthorne effect has been linked with numerous other terms,
including: epistemic feedback, systemic bias, implicit social cognition,
and continuous improvement.
History of Hawtorne
Experiments
The term gets its name
from a factory called the Hawthorne Works, where a series of experiments
on factory workers were carried out between 1924 and 1932.
There were many types of experiments conducted on the employees, but the
purpose of the original ones was to study the effect of lighting on
workers productivity. Researchers found that productivity almost always
increased after a change in illumination but later returned to normal
levels. This effect was observed for minute increases in illumination.
Over time changes in illumination had no measurable effect probably due
to regression brought on by the increased stress.
A second set of
experiments began and were supervised by Harvard University professors
Elton Mayo, Fritz Roethlisberger and William J. Dickson. They
experimented on other types of changes in the working environment, using
a study group of five young women. Again, no matter the change in
conditions, the women nearly always produced more. The researchers
reported that they had accidentally found a way to increase
productivity. The effect was an important milestone in industrial and
organizational psychology, organizational behavior, and Ergonomics.
However, some researchers have questioned the validity of the effect
because of the experimental design and faulty interpretations.
The Hawthorne
Experiments
Like the Hawthorne
effect, the definition of the Hawthorne experiments also varies. Most
industrial/occupational psychology and organizational behavior textbooks
refer to the illumination studies, and usually to the relay assembly
test room experiments and the bank wiring room experiments. Only
occasionally are the rest of the studies mentioned.
Illumination studies
The Hawthorne Works,
located in Cicero, Illinois, and just outside of Chicago, belonged to
the Western Electric Company, and the studies were funded by the
National Research Council of the National Academy of Sciences at the
behest of General Electric, the largest manufacturer of light bulbs in
the United States. The purpose was to find the optimum level of lighting
for productivity.
During two and a half years from 1924 to 1927, a series of illumination
level studies were conducted by the industrial engineers of Western
Electric Company Works in Cicero; Illinois.:
Study 1a: In the first experiment there was no control group. The
researchers experimented on three different departments; all showed an
increase of productivity, whether illumination increased or decreased.
Study 1b: A control group had no change in lighting, while the
experimental group got a sequence of increasing light levels. Both
groups substantially increased production, and there was no difference
between the groups. This naturally piqued the researchers' curiosity.
Study 1c: The researchers decided to see what would happen if they
decreased lighting. The control group got stable illumination; the other
got a sequence of decreasing levels. Surprisingly, both groups steadily
increased production until finally the light in experimental group got
so low that they protested and production fell off.
Study 1d: This was conducted on two women only. Their production
stayed constant under widely varying light levels. It was found that if
the experimenter said bright was good, they said they preferred the
light; the brighter they believed it to be, the more they liked it. The
same was true when he said dimmer was good. If they were deceived about
a change, they said they preferred it. Researchers concluded that their
preference on lighting level was completely subjective - if they were
told it was good, they believed it was good and preferred it, and vice
versa.
At this point, researchers of Western Electric realized that something
else besides lighting was affecting productivity. They suspected that
the supervision of the researchers had some effect, so they ended the
illumination experiments in 1927. Although in most cases workers
generally reduce productivity during time studies in an effort to gain
additional time to complete tasks there are cases where workers will
increase their activity if rewards are promised. The studies' results
and conclusions are still in question and under considerable
interpretation.
During 1927, a Harvard professor, Elton Mayo, along with his associates,
joined the study as consultants. The experiments started again and
lasted through to 1932. These experiments consisted of redesigning jobs,
changing workday and workweek lengths, adding additional rest times and
studying the factor of wage changes, which were the first changes
measured at the Hawthorne Facility under the expectation that economic
factors would have the greatest effect.
Relay assembly
experiments
The researchers wanted
to identify how other variables could affect productivity. They chose
two women as test subjects and asked them to choose four other workers
to join the test group. Together the women worked in a separate room
over the course of five years (1927-1932) assembling telephone relays.
Output was measured mechanically by counting how many finished relays
each dropped down a chute. This measuring began in secret two weeks
before moving the women to an experiment room and continued throughout
the study. In the experiment room, they had a supervisor who discussed
changes with them and at times used their suggestions. Then the
researchers spent five years measuring how different variables impacted
the group's and individuals' productivity. Some of the variables were:
changing the pay rules so that the group was paid for overall group
production, not individual production
giving two 5-minute breaks (after a discussion with them on the
best length of time), and then changing to two 10-minute breaks (not
their preference). Productivity increased, but when they received six
5-minute rests, they disliked it and reduced output.
providing food during the breaks
shortening the day by 30 minutes (output went up); shortening it
more (output per hour went up, but overall output decreased); returning
to the earlier condition (where output peaked).
Changing a variable
usually increased productivity, even if the variable was just a change
back to the original condition. However it is said that this is the
natural process of the human being to adapt to the environment without
knowing the objective of the experiment occurring. Researchers concluded
that the workers worked harder because they thought that they were being
monitored individually.
Researchers hypothesized that choosing one's own coworkers, working as a
group, being treated as special (as evidenced by working in a separate
room), and having a sympathetic supervisor were the real reasons for the
productivity increase. One interpretation, mainly due to Mayo, was that
"the six individuals became a team and the team gave itself
wholeheartedly and spontaneously to cooperation in the experiment."
(There was a second relay assembly test room study whose results were
not as significant as the first experiment.)
Bank wiring room experiments
The purpose of the next study was to find out how payment incentives
would affect group productivity. The surprising result was that they had
no effect. Ironically, this contradicted the Hawthorne effect: although
the workers were receiving special attention, it didnt affect their
behavior or productivity. However, the informal group dynamics studied
were a new milestone in organizational behavior.
The study was conducted by Mayo and W. Lloyd Warner between 1931 and
1932 on a group of 14 men who put together telephone switching
equipment. The researchers found that although the workers were paid
according to individual productivity, productivity did not go up because
the men were afraid that the company would lower the base rate. The men
also formed cliques, ostracized coworkers, and created a social
hierarchy that was only partly related to the difference in their jobs.
The cliques served to control group members and to manage bosses; when
bosses asked questions, clique members gave the same responses, even if
they were untrue.
Interviewing
Experiment
In this study all the
workers working at the Hawthorne Plant were individually interviewed. At
first the interviewers asked a specific set of questions. But that was
not of much help as the answers given by workers were very vague and
subjective. Then it was decided to let workers speak their mind. It had
great result as workers were able to air their grievances. This had a
positive effect on their productivity.
Mica splitting test room
In this study from 1928 to 1930, workers in the mica splitting room were
paid by individual piece rate, rather than by group incentives. However,
work environment conditions were changed to see how they affected
productivity. The study lasted fourteen months and productivity
increased by fifteen percent.
Definitions
Here are some sample definitions of the Hawthorne effect, showing how
differently it can be defined:
An experimental effect in the direction expected but not for the
reason expected; i.e., a significant positive effect that turns out to
have no causal basis in the theoretical motivation for the intervention,
but is apparently due to the effect on the participants of knowing
themselves to be studied in connection with the outcomes measured.
The Hawthorne Effect [is] the confounding that occurs if
experimenters fail to realize how the consequences of subjects'
performance affect what subjects do.
People singled out for a study of any kind may improve their
performance or behavior, not because of any specific condition being
tested, but simply because of all the attention they receive.
People will respond positively to any novel change in work
environment.
Interpretation,
criticism, and conclusions
H. McIlvaine Parsons
(1974) argues that in 2a (first case) and 2d (fourth case) they had
feedback on their work rates; but in 2b they didn't. He argues that in
the studies 2a-d, there is at least some evidence that the following
factors were potent:
1. Rest periods
2. Learning, given feedback i.e. skill acquisition
3. Piecework pay where an individual does get more pay for more work,
without counter-pressures (e.g. believing that management will just
lower pay rates).
Clearly the variables the experimenters manipulated were neither the
only nor the dominant causes of productivity changes. One
interpretation, mainly due to Mayo, was that "the six individuals became
a team and the team gave itself wholeheartedly and spontaneously to
cooperation in the experiment." In 1955 Landsberger reinterpreted the
experimental outcomes as the more general result of being observed and
labeled this result the "Hawthorne effect."
Parsons redefines "the
Hawthorne effect as the confounding that occurs if experimenters fail to
realize how the consequences of subjects' performance affect what
subjects do" [i.e. learning effects, both permanent skill improvement
and feedback-enabled adjustments to suit current goals]. So he is saying
it is not attention or warm regard from experimenters, but either a)
actual change in rewards b) change in provision of feedback on
performance. His key argument is that in 2a the "girls" had access to
the counters of their work rate, which they didn't previously know at
all well.
It is notable however that he refuses to analyze the illumination
experiments, which don't fit his analysis, on the grounds that they
haven't been properly published and so he can't get at details, whereas
he had extensive personal communication with Roethlisberger and Dickson.
It's possible that the
illumination experiments were explained by a longitudinal learning
effect. But Mayo says it is to do with the fact that the workers felt
better in the situation, because of the sympathy and interest of the
observers. He does say that this experiment is about testing overall
effect, not testing factors separately. He also discusses it not really
as an experimenter effect but as a management effect: how management can
make workers perform differently because they feel differently. A lot to
do with feeling free, not feeling supervised but more in control as a
group. The experimental manipulations were important in convincing the
workers to feel this way: that conditions were really different. The
experiment was repeated with similar effects on mica splitting workers.
References to the "the
Hawthorne effect" rely on Mayo's interpretation in terms of workers'
perceptions, but the data show strikingly continuous improvement. It
seems quite a different interpretation might be possible: learning,
expertise, reflection -- all processes independent of the experimental
intervention. However, the usual Mayo interpretation is certainly a real
possible issue in designing studies in education and other areas,
regardless of the truth of the original Hawthorne study.
Recently the issue of
"implicit social cognition", i.e., how much weight is actually given to
what is implied by others' behavior towards us (as opposed to what they
say, e.g. flattery) has been discussed: this must be an element here
too.
Richard E. Clark and
Timothy F. Sugrue (1991, p.333) in a review of educational research say
that uncontrolled novelty effects (i.e. halo effect) cause on average
30% of a standard deviation (SD) rise (i.e. 50%-63% score rise), which
decays to small level after 8 weeks. In more detail: 50% of a SD for up
to 4 weeks; 30% of SD for 5-8 weeks; and 20% of SD for > 8 weeks, (which
is < 1% of the variance).
Can the research be trusted?
Candice Gleim says:
Broad experimental effects and their classifications can be found in
Donald T. Campbell & Stanley, J. C. (1966). Experimental and
quasi-experimental designs for research. Chicago: Rand McNally. and
Cook, T. D., & Campbell, D. T. (1979), Quasi-Experimentation: Design and
Analysis Issues. Houghton Mifflin Co.
Michael L. Kamil says:
You might want to be a bit careful about the scientific basis for the
Hawthorne effect. Lee Ross has brought the concept into some question.
There was a popular news story in the New York Times a couple of years
ago:
David Carter-Tod says:
A psychology professor at the University of Michigan, Dr. Richard
Nisbett, calls the Hawthorne effect 'a glorified anecdote.' 'Once you've
got the anecdote,' he said, 'you can throw away the data.'" A dismissive
comment which back-handedly tells you something about the power of
anecdote and narrative.
Harry Braverman say in "Labor and Monopoly Capital": The Hawthorne tests
were based on behaviorist psychology and were supposed to confirm that
workers performance could be predicted by pre-hire testing. However, the
Hawthorne study showed "that the performance of workers had little
relation to ability and in fact often bore a reverse relation to test
scores...". What the studies really showed was that the workplace was
not "a system of bureaucratic formal organization on the Weberian model,
nor a system of informal group relations, as in the interpretation of
Mayo and his followers but rather a system of power, of class
antagonisms". This discovery was a blow to those hoping to apply the
behavioral sciences to manipulate workers in the interest of management.
What may be wrong about the quoted dismissiveness is that there was not
one study, but three illumination experiments, and 4 other experiments:
only one of these seven is alluded to. What is right is that a) there
certainly are significant criticisms of the method that can be made and
b) most subsequent writing shows a predisposition to believe in the
Hawthorne effect, and a failure to read the actual original studies.
Can the literature be
trusted?
The experiments were
quite well enough done to establish that there were large effects due to
causal factors other than the simple physical ones the experiments had
originally been designed to study. The output ("dependent") variables
were human work, and the educational effects can be expected to be
similar (but it is not so obvious that medical effects would be). The
experiments stand as a warning about simple experiments on human
participants viewed as if they were only material systems. There is less
certainty about the nature of the surprise factor, other than it
certainly depended on the mental states of the participants: their
knowledge, beliefs, etc.
Candidate causes are:
1. Material factors, as originally studied e.g. illumination, ...
2. Motivation or goals e.g. piecework, ...
3. Feedback: can't learn skill without good feedback. Simply
providing proper feedback can be a big factor. This can often be a side
effect of an experiment, and good ethical practice promotes this
further. Yet perhaps providing the feedback with nothing else may be a
powerful factor.
4. The attention of experimenters.
Parsons implies that (4) might be a "factor" as a major heading in our
thinking, but as a cause can be reduced to a mixture of (2) and (3).
That is: people might take on pleasing the experimenter as a goal, at
least if it doesn't conflict with any other motive; but also, improving
their performance by improving their skill will be dependent on getting
feedback on their performance, and an experiment may give them this for
the first time. So you often won't see any Hawthorne effect -- only when
it turns out that with the attention came either usable feedback or a
change in motivation.
Adair (1984): warns of gross factual inaccuracy in most secondary
publications on Hawthorne effect. And that many studies failed to find
it, but some did. He argues that it should be viewed as a variant of
Orne's (1973) experimental demand characteristics. So for Adair, the
issue is that an experimental effect depends on the participants'
interpretation of the situation; that this may not be at all like the
experimenter's interpretation and the right method is to do
post-experimental interviews in depth and with care to discover
participants' interpretations. So he thinks it is not awareness per se,
nor special attention per se, but participants' interpretation must be
investigated in order to discover if/how the experimental conditions
interact with the participants' goals (in participants' views). This can
affect whether participants' believe something, if they act on it or
don't see it as in their interest, etc.
Rosenthal and Jacobson
(1992) ch.11 also reviews and discusses the Hawthorne effect.
Its interpretation in management research The research was and is
relevant firstly in the 'Human Resources Management' movement. The
discovery of the effect was most immediately a blow to those hoping to
apply the behavioral sciences to manipulate workers in the interest of
management.
Other interpretations it has been linked to are: Durkheim's 'anomie'
concept; the Weberian model of a system of bureaucratic formal
organization; a system of informal group relations, as in the
interpretation of Mayo and his followers; a system of power, of class
antagonisms.
Summary view of
Hawthorne Experiments
In the light of the
various critiques, we can see the Hawthorne effect at several levels.
At the top level, it
seems clear that in some cases there is a large effect that
experimenters did not anticipate, that is due to participants' reactions
to the experiment itself. It only happens sometimes. So as a
methodological heuristic (that you should always think about this issue)
it is useful, but as an exact predictor of effects, it is not: often
there is no Hawthorne effect of any kind. To understand when and why we
will see a Hawthorne or experimenter effect, we need more detailed
considerations.
At a middle level Adair
(1984) says that the most important (though not the only) aspect of this
is how the participants interpret the situation. Interviewing them
(after the "experiment" part) would be the way to investigate this.
This is important
because factory workers, students, and most experimental participants
are doing things at the request of the experimenter. What they do
depends on what their personal goals are, how they understand the task
requested, whether they want to please the experimenter and/or whether
they see this task as impinging on other interests and goals they hold,
what they think the experimenter really wants. Besides all those issues
that determine their goals and intentions in the experiment, further
aspects of how they understand the situation can be important by
affecting what they believe about the effects of their actions. Thus the
experimenter effect is really not one of interference, but of a possible
difference in the meaning of the situation for participants and
experimenter. Since all voluntary action (i.e. actions in most
experiments) depends upon the actor's goals AND on their beliefs about
the effects of their actions, differences in understanding of the
situation can have big effects.
At the lowest level is
the question of what the direct causal factors might be. These could
include::
Material ones that are intended by the experimenter
Feedback that an experiment might make available to the
participants
Changes to goals, motivation, and beliefs about action effects
induced by the experimental situation.
References
http://en.wikipedia.org/wiki/Hawthorne_effect
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