Personality traits are less stable than we think

We tend to think of personality traits such as generosity or meanness as stable phenomena, but a number of psychological studies strongly suggest that they are much more dependent on the particular situation we find ourselves in than we usually think.

The psychologist, John Doris, has collected some examples in his book "Lack of Character". In one of these the subjects were much more likely to help someone who dropped their papers outside a phone box if they had just found a coin in the coin-return slot than if there was no coin there. In a famous experiment with Princeton theology students, the students were asked to fill in a questionnaire in one building and then go to another to give a short presentation. Some of them were then told on their way between the two places that they were running late, others that they were on time and a third group that they were ahead of schedule. Those in a hurry were less likely to help an actor they came across lying in a doorway in obvious distress, than those who were on time.

Stanley Milgram found in his obedience experiments at Yale that most of the subjects who were playing the role of teachers were prepared to administer incremental electric shocks to others playing the role of learners for incorrect answers given by pressing a button, even if they heard loud banging noises coming from the other room where they thought the learner was located (in fact both the electirc shocks and the banging noises were faked) if they had been ordered to do so by someone whom they believed was in charge of the experiment.

The Stanford Prison Experiment which was supposed to run for two weeks was stopped after six days because the normal students who had taken the role of the prison guards, were acting with great cruelty, e.g. making their fellow students who were playing the parts of the prisoners clean out the toilets with their bare hands. These findings can be explained, at least to some extent, by our need to conform to group norms, and especially to those in positions of authority within the group (after all, we can only survive in groups with at least some minimal co-operation).

In 1948 the psychologist, Bertram Forer, gave subjects the description of a personality and asked them to rate how accurate the description was of themselves. On average, the subjects rated its accuracy as 4.26 out of 5. Forer thought that we find descriptions of personality convincing because we tend to notice the elements which fit our self-image, disregard those which do not fit and underestimate the extent to which some of the descriptions apply to virtually everyone (e.g. "at times you are extroverted ... at other times ... introverted"). This has come to be known as the Forer or Barnum Effect.

Given that personality traits are less stable and more situation-dependent than we normally think they are, what lessons can we learn from this? One of the lessons we can learn is to be more cautious about judging the behaviour of others unless we know enough about the particular circumstances in which the behaviour took place. Secondly, Philip Zimbardo, who conducted the Stanford Prison Experiment, thinks that there are some simple ways of trying to improve our own character, for instance, if just tell ourselves that we are very generous this can motivate us to act in a more generous way in future. Zimbardo himself tries to teach young people to see themselves as "heroes in waiting" so that they spring into action to help someone in distress rather than remain as passive bystanders.

Paul Crichton
23. September 2011

For more information on this topic, see:

The Ego Trick, Julian Baggini, 2011, pp154–175
Lack of Character, John Doris, 2002

The individual in a social world: Essays and experiments. Milgram, S. (1977), 3rd expanded edition published 2010

Stanford prison experiment: A simulation study of the psychology of imprisonment, Philip G. Zimbardo, 1972