Evaluating the Learning of Stimulus-Control Associations Through Incidental Memory of Reinforcement Events

Cognitive control describes the ability to use internal goals to strategically guide how we process and respond to our environment. Changes in the environment lead to adaptation in control strategies. This type of control learning can be observed in performance adjustments in response to varying proportions of easy to hard trials over blocks of trials on classic control tasks. Known as the list-wide proportion congruent (LWPC) effect, increased difficulty is met with enhanced attentional control. Recent research has shown that motivational manipulations may enhance the LWPC effect, but the underlying mechanisms are not yet understood. We manipulated Stroop proportion congruency over blocks of trials and, after each trial, provided participants with either performance-contingent feedback ("correct/incorrect") or noncontingent feedback ("response logged") above trial-unique, task-irrelevant images (reinforcement events). The LWPC task was followed by a surprise recognition memory task, which allowed us to test whether attention to feedback (incidental memory for the images) varies as a function of proportion congruency, time, performance contingency, and individual differences. We replicated a robust LWPC effect in a large sample (N = 402) but observed no differences in behavior between feedback groups. Importantly, the memory data revealed better encoding of feedback images from context-defining trials (e.g., congruent trials in a mostly congruent block), especially early in a new context and in congruent conditions. Individual differences in reward and punishment sensitivity were not strongly associated with control-learning effects. These results suggest that statistical learning of contextual demand may have a larger impact on control learning than individual differences in motivation.