Sometimes, when a group carries out research where the performance of the participants in a task is evaluated, they do it over and above what is usual for them. This is not due to a newly discovered innate talent, but to what scientists call the ‘Hawthorne effect’ .

This effect, discovered almost by accident by Elton Mayo more than 80 years ago, seems to manifest itself especially in research situations. We will briefly explain its history and the different interpretations it has received.

Experiments in the Hawthorne factory

E. Mayo, an Austrian industrial psychologist, carried out a series of experiments at the Hawthorne factory between 1924 and 1933 to investigate the relationship between lighting conditions and the productivity of its employees.

In the initial phase of the study, Mayo divided the workers into two groups: one worked under the same light conditions and the other under a light that the experimenters gradually turned off. Contrary to expectations, both groups gradually increased their performance.

This unexpected fact motivated Mayo to continue evaluating the relationships between performance and other physical variables , such as those that produce fatigue and monotony in workers. Again, it was found that even if the changes introduced were a priori harmful, performance improved.

What was most surprising about the study was that, even in the stages when conditions were less favourable, there was not a decline in production as expected, which highlighted the influence of variables other than those initially considered relevant by the researchers, such as social factors, in explaining productivity.

The conclusions of the May experiment

The Mayo group concluded that this was due to the research situation itself and the presence of experimenters, a phenomenon that in 1953 was called the “Hawthorne effect” after the facilities where the research was conducted.

However, the workers had a different opinion . For them, the factor that had the most weight in the continuous increase in performance was the improvement in personal relations between workers and management. It seems that, in order to promote collaboration, the experimenters created a warm climate where special attention was paid to the demands of the workers and they felt listened to.

This suggestion became a conclusion and served as the basis, years later, for a new trend in business administration and management that would emphasize human relations, and would soon replace the trend that emphasized efficiency and productivity through scientific study.

What we know about the Hawthorne effect

In general, the most widely accepted modern definition describes the Hawthorne effect as follows: the Hawthorne effect is the improvement of results simply by being part of an investigation or the increase in performance due to the introduction of a certain change in a study.

Social psychologists propose that subjects, upon realizing that they are being observed, generate beliefs about what the experimenters expect of them. Motivated by conformity and social desirability, individuals change their behaviour to align it with these beliefs.

It is impossible to give a precise answer about their mechanisms, because each discipline has taken the name of “Hawthorne effect” to describe different phenomena, and therefore propose different explanations. Because of this, their meaning has been mutating and investigating the effect has been confusing and not very rigorous.

From the multiple definitions proposed by social psychologists, six characteristics are extracted that are typical of situations where the Hawthorne effect occurs:

  • News of the situation.
  • Artificiality of the situation.
  • Changes made to the experiment.
  • The worker’s belief that the situation is beneficial to him.
  • Awareness of being studied or observed by an evaluator.
  • Reduced worker boredom.

Often, researchers establish a good relationship with the subjects in order for them to collaborate with them. In this way, the experimenter may be introducing changes in behaviour through the creation of a warm climate and an environment where workers’ complaints and suggestions are heard.

Criticism of the concept

In the context of research, the Hawthorne effect is any alteration in behaviour as a result of observation or study. For this reason, some authors point out that this is an a posteriori interpretation of unexpected results, especially when these are contrary to the initial hypothesis.

Even the original investigations of May have been questioned and criticized many times . Alternative interpretations to the performance increase have been offered that shake the foundations of the research.

For example, the cessation of strict supervision of employers, receiving positive attention, the introduction of rest breaks or the perceived possibility of losing one’s job are alternative explanations to those originally proposed by Mayo and his collaborators.

The experiments also received other negative criticisms of their design; the experts who worked on them did not have research training and the results were not sufficiently contrasted.

Today most research devoted to the validation of the Hawthorne effect concludes that there is not enough evidence to support its existence.

Thus, a concept that for years has served as a scapegoat in the scientific literature, is likely to be no more than the reflection of a bias in the interpretation of results decades ago.