Figure 2: Behavioural task and results from fMRI experiment.
From: Striatal prediction errors support dynamic control of declarative memory decisions
(a) Participants completed a recognition memory test during fMRI scanning. On each trial, they made an old/new decision by pressing one of two buttons. They indicated their confidence using a continuous confidence scale: holding down the response button caused a black bar to move within the rectangle below their chosen response. They released the button to lock-in their confidence rating such that high confidence corresponded to the top of the rectangle. Positive (‘Correct!’) or negative (‘Incorrect!’) feedback was provided on each trial following a jittered fixation delay. In the fMRI experiment, false positive feedback was provided on ∼70% of incorrect old responses. Veridical positive and negative feedback was provided on all other trials. (b) The biased feedback paradigm elicited a liberal shift in criterion (that is, more negative criterion values) over the course of the recognition test. Error bars are s.e.m.
