Fig 6. Behavioural signatures distinguishing “low” and “high” bias participants.

(A) Task conditions. The ‘Symmetric’ condition was characterised by a stable reward contingency and no correct option, because the two options had equal reward probabilities. The ‘Asymmetric conditions’ were also characterised by a stable reward contingency but had a correct option, since one option had a higher reward probability than the other. The ‘Reversal’ condition was characterised by an unstable reward contingency: after 12 trials the reward probability reversed across symbols, so that the former correct option became the incorrect one, and vice versa. Note that the number of trials refers to one session and participants performed two sessions, each involving new pairs of stimuli (192 trials in total). (B) and (C) Behavioural results as a function of the task conditions in Experiment 1 and Experiment 2, respectively. Each column presents the result of the corresponding condition presented in (A). In the Symmetric condition, where there was no correct option, we calculated the “preferred choice rate”, which was the choice rate of the most frequently chosen option (by definition, this was always greater than 0.5). In the Asymmetric and the Reversal conditions we calculated the correct choice rate. In the Reversal condition the correct choice rate was split between the two learning phases. ***P<0.001 and *P<0.05, two-tailed paired t-test.