Automatic, not inflexible: Implicit adaptation is modulated by goal-directed attentional demands

Implicit adaptation is a well-established learning process that recalibrates movements based on sensory prediction errors. While often described as automatic and inflexible, its expression can vary depending on contextual factors such as task outcomes or the presence of salient distractors. Here, we examined whether implicit adaptation is sensitive to attentional demands imposed by a concurrent visual task, rather than by task-irrelevant stimuli. Across two experiments, we used clamped feedback to measure implicit adaptation while human adults performed a rapid serial visual presentation (RSVP) task. In Experiment 1, participants performing the RSVP task showed modest initial enhancements in implicit adaptation relative to a single task condition, despite a decline in RSVP accuracy when exposed to the clamped feedback. In Experiment 2, adding response-contingent feedback to the RSVP task led to stronger and more sustained implicit adaptation compared to the single task condition. These findings are inconsistent with interference-based accounts, which predict that attentional demands should suppress implicit adaptation, and challenge the view that implicit adaptation operates independently of cognitive states. Instead, they suggest that implicit adaptation is sensitive to goal-directed attention. Model-based analyses revealed that the dual task conditions were associated with increased error sensitivity, marginally lower retention, and a strong negative correlation between these parameters—suggesting a reconfiguration of this learning process. Rather than being suppressed by or immune to cognitive demands, implicit adaptation seems to be an automatic yet flexible learning mechanism that can be modulated by attentional states.