Testing Bayesian Updating with the AP Top 25

Most studies of Bayesian updating use experimental data. This paper uses a non-experimental data source--the voter ballots of the Associated Press (AP) college football poll, a weekly subjective ranking of the top 25 teams--to test Bayes' rule as a descriptive model. I find that voters sometimes underreact to new information, sometimes overreact, and at other times their behavior is consistent with estimated Bayesian updating. A unifying explanation for the disparate results is that voters are more responsive to information that is more salient (i.e., noticeable). In particular, voters respond in a ``more Bayesian'' way to losses and wins over ranked teams, as compared to wins over unranked teams, and voters seem unaware of subtle variation in the precision of priors