When people infer causes about events or behaviours order to make sense of them, they are said to be making ‘attributions’. In psychological research, attributions can be classified according to a two-dimensional model: internal vs. external and stable vs. unstable.
Internal and external refer to the nature of an inference that someone might make. Internal – or dispositional – attributions are inferences that identify causes to be traits, abilities, feelings, or similar internal phenomena. External – or situational – attributions are inferences that identify causes to be circumstantial or similar external phenomena.
Stable and unstable refer to the rigidity or permanence of an inference that someone might make. Stable attributions are inferences based on the assumption of unchangeable circumstances, of permanence. Unstable attributions are inferences based on the assumption of changeable circumstances, of flux.
The idea of attributions can be narrowed and focused into two contrasting hypotheses that can be used in experimentation to make assertions about human behaviour. On the one hand, there is the situational hypothesis, which asserts that the cause of an observed behaviour is caused by factors that originate from an environment, from external sources.
On the other there is the dispositional hypothesis, which asserts that the cause of an observed behaviour is caused by factors that originate from traits, from internal sources.
The Stanford Prison Simulation
The most famous experiment to investigate the dispositional hypothesis is undoubtedly the Stanford Prison Simulation. In 1971, Philip Zimbardo conducted a simulation at Stamford University to investigate how readily people would conform to the roles of guard and prisoner in a role-playing exercise that simulated prison life.
At the time, there was a lot of brutality being reported in American prisons. As a result, the US Office of Naval Research funded Zimbardo to investigate whether the cause of the brutality was the personalities of the guards (i.e. a dispositional attribution) or the prison environment itself (i.e. a situational attribution).
Zimbardo created a mock prison in the basement of the Stanford University Psychology Department and sent out an advertisement to students asking for participants. Over 70 people applied to be either a guard or an inmate. From 24 successful healthy male applicants, two were reserves and one withdrew, leaving 10 prisoners and 11 guards for the experiment.
The experiment attempted to be as realistic as possible. The ‘guards’ worked shifts and wore khaki uniforms with dark shades, the ‘prisoners’ were arrested at their home and taken to the cells blindfolded, had their possessions removed and were assigned numbers and uniforms. Importantly, guards were instructed to use any means necessary to keep law and order, except for using physical violence.
Zimbardo acted as the warden and observed the behaviour of both guards and inmates. He found that both sets of participants adopted their respective roles extraordinarily quickly, with the guards developing brutal behaviour and the prisoners developing submissive behaviour. The experiment was intended to last for a fortnight, but it was terminated on the sixth day due to the severity of those behaviours.
The conclusion of the experiment was that people will readily conform to social roles, especially if those roles are strongly stereotyped (i.e. a closed system of prisoners vs. guards). None of the participants showed signs of the brutal or submissive behaviour before the experiment, which suggested that the prison environment, the system in which they were placed, was the driving factor for their behaviour.
Because of this, the Stanford Prison Simulation rejected the dispositional hypothesis and accepted the situational hypothesis.