Shaver (1970) had two independent variables, severity of the accident outcome (severity) and similarity of the subjects to the transgressor.
Severity was manipulated by giving subjects in different conditions different scenarios:
- mild outcome = the boy had the metal splinter in his wrist
- severe outcome = the boy had a metal splinter in his eye
How did Shaver “manipulate” the IV similarity (similar/dissimilar)?
Shaver, K.G. (1970). Defensive attribution: Effects of severity and relevance on the responsibility assigned for an accident In: Journal of Personality and Social Psychology, 14(2): pp 101-113.