Figure 1.

Rule learning task and behavior. (a) Participants completed six 20-trial blocks of a rule-learning task. Trials were divided into three phases: cue, response and feedback, each separated by a random 4–6 s delay. During the cue phase (2 s), the stimulus to be categorized was presented in the center of the screen. During the response phase (2 s), a question mark was presented in the center of the screen, prompting participants to press a button to respond. During the feedback phase (2 s), a message was displayed indicating whether the response was correct. (b) Average reaction times for each of the rule blocks, ordered by mean reaction time. Although there was heterogeneity in reaction time between rules, only the difference between A and (A and B) was significant when correcting for multiple comparisons. (c) Left panels show mean participant accuracy and Bayesian rule learning model predictions, without any parameter fitting, for each rule. To the right is the average performance, collapsed across trials, referenced against the performance of an optimal version of the Bayesian model for each rule. The dotted line represents chance performance. Participants learned to respond well-above chance and remarkably close to optimal performance for all rules. All error bars represent bootstrapped estimates of the standard error of the mean across subjects.