Errata for Kirby (2013)

Bayes Optimal Classifier

The caption for Figure 2(B) is incorrect. This does not show the optimal categorization function ('choose the category with the highest a a posteriori probability') but instead the posterior probability of category c1 (consistent with a frequency-tracking decision rule, i.e. 'choose category c1 with probability p(c1)'). A more accurate figure illustrating the decision bound is Figure 2.8 of Kirby (2010). In the simulations reported here, the Bayes optimal decision rule, not the frequency-tracking rule, was used (cf. Kirby 2010:51-2). (Hat tip to Janet Pierrehumbert)