Figure 2.

Experiment 2 showed that improved adaptation requires a history of adaptation to task errors. A, Mean reach directions for all cycles for all groups (groups experiencing CW rotations sign-flipped to collapse across CW and CCW groups). B, The StandardTE^TrainNoTE^TEST group experienced standard task errors at training, but no task errors at test. E, The RandomTE^Train NoTE^TEST group experienced random task errors at training but no task errors at test. H, The NoTE^TrainStdTE^TEST group experienced no task errors at training, and standard task errors at test. All participants were deprived of task errors (i.e., had the no-task error manipulation) at washout. C, F, I, Estimated marginal mean ± SEM adjusted for prerotation percent adaptation, where test phase adaptation is compared with naive controls (open symbols) experiencing the same task error manipulation. A history of adapting to standard task errors, but not adapting to random task errors, improved subsequent adaptation (C,F). In contrast, adaptation was unimproved without a history of task errors (I). D, G, J, Mean ± 95% CI of mean percent adaptation averaged from the first 5 cycles.