5 psychological experiments that changed our world

Here are the top 5 experiements that changed the way we think. Some are better known than others, some were quietly published in academic journals and their importance has only become clearer with time.


1- Arden House - Ellen Langer and Judith Rodin, 1976

On one floor of a care home for the elderly, residents were given choices about how to arrange their furniture, what films to watch and how to care for a plant they picked out. A second floor of residents were given no choices or responsibilities. Other than these differences, they shared the same quality of life, but 18 months later twice as many of the second group had died. Giving people a tiny degree of control over their lives had kept them healthier. This is less well-known than the other studies here, but it should be compulsory reading for anyone running a home or caring for older adults. Small changes can make a difference. (See Babayagas)

2 - Obedience to authority - Stanley Milgram, 1974

Volunteers were asked to give electric shocks to another supposed volunteer (really an actor) as punishment, in what they thought was a memory test. 65% of the people administered shocks that would have been fatal despite hearing cries of pain, simply because a man in a white coat told them to. This shows us where blind obedience can lead - and how unusual it is to question authority. Reassuringly, just hearing about this experiment makes people more likely to challenge what they're told.

3 - The nun study - Deborah Danner, 2001

This showed that our attitude to life can influence how long we live, and it was all done using one-page personal statements written by novice nuns in the 1930s. The nuns who used the greatest number of hopeful phrases in these statements lived on average 9.6 years longer than the least hopeful nuns. This is roughly the difference in life expectancy between a non-smoker and someone who smokes 20 a day.

4 - Stanford Prison experiment - Philip Zimbardo, 1971

Probably one of the best known studies ever conducted in psychology. A fake prison was created in the basement of Stanford University, and students were randomly assigned to the job of guard or prisoner. After just 6 days, the guards were treating the prisoners so cruelly that the experiment had to be stopped. Zimbardo's conclusion, that in certain situations, even good people can do dreadful things, continues to resonate.

5 - The pseudo-patient study - David Rosenhan, 1972

A psychologist and 8 of his friends were given psychiatric diagnoses and admitted to hospital, when in fact they had simply turned up at different hospitals claiming to hear a voice in their head saying "thud". The most fascinating aspect of this study is the way staff perceptions changed the moment these people were classified as 'mentally ill'. They only had to take notes for the staff to deem it "writing behaviour". There is such power in the label "madness" and plenty of evidence, 35 years after this study, that mental illness is still stigmatised.

Claudia Hammond in Psychologies