Feedback delay attenuates implicit but facilitates explicit adjustments to a visuomotor rotation

We examined the effects of delaying terminal visual feedback on the relative contribution of explicit and implicit components of adaptation to a visuomotor rotation. Participants practiced a 30° rotation while receiving terminal visual feedback with either a short (0ms), medium (200ms), or long (1500ms) delay. Explicit and implicit adjustments were dissociated by a series of posttests. While overall adaptation did not differ significantly between groups, aftereffects progressively decreased with increasing feedback delay. Moreover, explicit knowledge of the rotation increased in both the medium and high delay groups relative to the short delay group, but did not differ between the former two. This finding of feedback delay differentially affecting implicit adjustments as indexed by aftereffects and conscious strategic corrections based on explicit knowledge of the transformation substantiates the importance of distinguishing implicit and explicit components of adaptation even with rotations of smaller size and emphasizes the need to consider time delays in the interpretation of adaptation experiments and potentially in the design of training environments.