Hawthorne and Placebo Effect: Do Treatments Really Work?

Psychology 101: The 101 Ideas, Concepts and Theories that Have Shaped Our World - Adrian Furnham 2021

Hawthorne and Placebo Effect: Do Treatments Really Work?

The sound of the flute will cure epilepsy and sciatic gout. (Theophrastus, 280 BC Physics)

Time is the great physician. (Benjamin Disraeli, Henrietta Temple, 1880)

Noble deeds and hot baths are the best cures for depression. (Dodie Smith, I Capture the Castle, 1980)

There are two expressions in psychology, the one arising from work and the other health psychology, which have very different origins but very similar meanings. They refer to the fact that interventions or treatment appear to work but not for the reason people think. It is about how people are treated rather than what medicine or management techniques they are given.


This refers to the fact that people change their behaviour because they are being treated differently and observed, not for more obvious reasons.

The idea originated from studies done in the 1920s which all aimed at changing the physical nature of the workplace to increase productivity. The first studies were intended to identify lighting levels that would produce optimal productivity at cheapest cost. It posed a simple question: Would the quality of the lighting in a manual dexterity task affect the speed and quality of production? In the first illumination experiment, however, productivity increased when illumination was increased and when it was decreased. Although conditions were systematically changed the resultant productivity changed little.

Other studies continued and looked at the effect of longer and shorter breaks, free food etc. but they could not understand the results. Eventually it dawned on them that it was not the light, or breaks or food that made the difference but the way the workers were being treated by the experimenters. It heralded the Human Relations movement which argued:

Individual work behaviour is rarely a pure consequence of simple cause and effect relationships, but rather is determined by a complex set of factors.

The informal or primary work group/team develops its own set of norms which has a big impact on morale and productivity.

The social structure of these informal groups is maintained through job-related symbols of prestige and power.

Supervisors need to listen to the personal context of employee complaints to understand the unique needs and satisfactions of each individual.

Awareness of employee sentiments and employee participation can reduce resistance to change.

So when you hear someone say ’it is a pure Hawthorne effect’ they mean the action that people claim to be the result of some activity is actually the result of them being treated differently.


Placebo means ’to please’. The concept of mind over matter in the world of health has been known for centuries. Modern research in the area is usually attributed to a paper written in the American Dental Association journal over 50 years ago. Henry Beecher shocked the medical world by claiming that just placebo procedures like giving sugar pills or even a sympathetic physical examination of the patient would lead to an improvement in 30 per cent of cases.

Some believe placebo effects are more effective for psychological rather than physical illnesses. One important recent study showed that nearly 60 per cent of placebo controlled patients did better than average waiting-list control patients, showing the power of the placebo.

It is possible to distinguish between active placebos which have effects, but not on the problem they are meant to cure, and inactive effects which have measurable direct or side effects.

Placebos administered in an orthodox medical context have been shown to induce relief from symptoms in an impressively wide array of illnesses, including allergies, angina pectoris, asthma, cancer, cerebral infarction, depression, diabetes, enuresis, epilepsy, insomnia, Meunière’s disease, migraine, multiple sclerosis, neurosis, ocular pathology, Parkinsonism, prostatic hyperplasia, schizophrenia, skin diseases, ulcers and warts.

Adverse effects of placebo administration have also been noted in many studies. These include dependence, symptom worsening (the nocebo effect) and a multitude of side effects, both subjective (headache, concentration difficulties, nausea, etc.) and objectively visible (skin rashes, sweating, vomiting).

Differences between placebo responders and non-responders have long been of interest. Attempts to spot such differences on socio-demographic characteristics (age, gender, ethnicity, educational level) have generally yielded weak and inconclusive findings. Other studies have looked at possible individual differences in intelligence and personality. Any patient may benefit from the placebo effect, not just a gullible minority.

What type of placebo works best? The colour and size of capsules and pills have been repeatedly subject to experimental manipulation, but with little reliable impact. It does not seem to make much difference. One researcher reported that for a placebo to be maximally effective it should be very large and either brown or purple or very small and either bright red or yellow.

More serious, ’major’ or invasive procedures do appear to have stronger placebo effects. Injections per se appear to have a greater impact than pills, and even placebo surgery (where people are cut open and sewn up with little or nothing done) has yielded high positive response rates.

Those therapists who also exhibit greater interest in their patients, greater confidence in their treatments and higher professional status, all appear to promote stronger placebo effects in their patients.

Randomized, double-blind, control trials

The placebo effect is both a blessing and a curse. A blessing for all therapists irrespective of what treatment they prescribe. They are a curse for scientists who try to evaluate the real effect of interventions. The placebo controlled, randomized, double-blind study has become the gold standard of scientific research to assess therapy and ’discount’ any placebo effects.


Mayo, E. (1949). Hawthorne and the Western Electric Company, The Social Problems of an Industrial Civilization, Routledge.

Del Mar C., & Hoffman, T. (2015) A guide to performing a peer review of randomized controlled trials. BMC Medicine.