Pre-commitment and Updating Beliefs

Beliefs help individuals make predictions about the world. When those predictions are incorrect, it may be useful to update beliefs. However, motivated cognition and biases (notably, hindsight bias and confirmation bias) can instead lead individuals to reshape interpretations of new evidence to seem more consistent with prior beliefs. Pre-committing to a prediction or evaluation of new evidence before knowing its results may be one way to reduce the impact of these biases and facilitate belief updating. I first examined this possibility by having participants report predictions about their performance on a challenging anagrams task before or after completing the task. Relative to those who reported predictions after the task, participants who pre-committed to predictions reported predictions that were more discrepant from actual performance and updated their beliefs about their verbal ability more (Studies 1a and 1b). The effect on belief updating was strongest among participants who directly tested their predictions (Study 2) and belief updating was related to their evaluations of the validity of the task (Study 3). Furthermore, increased belief updating seemed to not be due to faulty or shifting memory of initial ratings of verbal ability (Study 4), but rather reflected an increase in the discrepancy between predictions and observed outcomes (Study 5). In a final study (Study 6), I examined pre-commitment as an intervention to reduce confirmation bias, finding that pre-committing to evaluations of new scientific studies eliminated the relation between initial beliefs and evaluations of evidence while also increasing belief updating. Together, these studies suggest that pre-commitment can reduce biases and increase belief updating in light of new evidence.