Dual-process decomposition in human sensorimotor adaptation

• Multiple processes contribute to adaptation of movements to systematic perturbations.
• Many qualitatively distinct dual-process decompositions have been proposed.
• Current evidence suggests the existence of two fundamental component processes.
• Future work must explore congruence across different decompositions.

Multiple distinct learning processes are known to contribute to sensorimotor adaptation in humans. It is challenging to identify and characterize these multiple processes, however, because only their summed contribution can typically be observed. A general strategy for decomposing adaptation into its constituent components is to exploit their differential susceptibility to specific experimental manipulations. Several such approaches have recently emerged which, taken together, suggest that two fundamental systems operate together to achieve the adapted state: one system learns slowly, is implicit, is temporally stable over short breaks, is expressible at low reaction times, and its properties do not change based on experience. The second learns rapidly, is explicit, requires a long preparation time to be expressed, and exhibits long-term memory for prior learning.