Surprise, defence, or making sense: what removes hindsight bias?

This paper examines predictions concerning the absence of hindsight bias. Some hypothesise that because hindsight bias increases with outcome "surprisingness", only unsurprising outcomes will remove it. Others suggest the opposite-that very surprising outcomes will reduce or reverse the bias. A proposed sense-making model suggests that unexpected outcomes (i.e., initially surprising) invoke greater sensemaking, which typically produces greater hindsight bias. If the process is not successful, however, the bias may be reduced or reversed. Expected outcomes will also produce little hindsight bias, but only because they invoke relatively little sensemaking in the first place. Feelings of surprise arising from sensemaking (i.e., resultant surprise) should be inversely related to hindsight bias. Results of four experiments provide support for the model. A secondary goal was to determine the boundaries of a defensive-processing mechanism also thought to reduce hindsight bias for negative, self-relevant outcomes. Results suggest that a sense of responsibility for the outcome may be necessary for defensive processing to be activated.