Investigating the Difference between Surprise and Probability Judgments


Surprise is often defined in terms of disconfirmed expectations, whereby the surprisingness of an event is thought to be dependent on the degree to which that event contrasts with a more likely, or expected, outcome. We propose that surprise is more accurately modelled as a manifestation of an ongoing sense-making process. Specifically, the level of surprise experienced depends on the extent to which an event necessitates representational updating. This sense-making view predicts that differences in subjective probability and surprise arise because of differences in representational specificity rather than differences between an expectation and an outcome. We describe two experiments which support this hypothesis. The results of Experiment 1 demonstrate that generalised representations can allow subjectively low probability outcomes to be integrated without eliciting high levels of surprise, thus providing an explanation for the difference between the two measures. The results of Experiment 2 reveal that the level of contrast between expectation and outcome is not correlated with the difference between probability and surprise. The implications for models of surprise are discussed.

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