Methods matter: Your measures of explicit and implicit processes in visuomotor adaptation affect your results

Area of Science:

• Motor control
• Cognitive psychology
• Neuroscience

Background:

• Motor adaptation involves explicit aiming and implicit recalibration.
• Existing methods to differentiate these processes have different assumptions.
• Direct (verbal reports) and indirect (exclusion) methods are commonly used.

Purpose of the Study:

• To directly compare verbal reporting and exclusion methods for measuring motor adaptation.
• To investigate the influence of reporting consistency (consistent vs. intermittent) on these measures.
• To determine if measurement methods impact the dissociation between explicit and implicit motor adaptation.

Main Methods:

• Participants performed visuomotor rotations under either consistent or intermittent verbal reporting conditions.
• Explicit motor adaptation was assessed using verbal reports of aiming adjustments.
• Implicit motor adaptation was assessed using the exclusion method.
• Measures were compared between the consistent and intermittent reporting groups.

Main Results:

• In consistent reporting, verbal reports and exclusion yielded similar results.
• In intermittent reporting, verbal reports indicated more explicit re-aiming and less implicit adaptation compared to exclusion.
• Post-learning re-testing with exclusion eliminated the observed differences.
• Selective decay of implicit adaptation may explain the transient differences.

Conclusions:

• Measurement methods significantly influence the observed amounts of explicit re-aiming and implicit adaptation.
• Discrepancies arise because different methods capture different components of motor adaptation.
• Understanding these methodological differences is crucial for accurately studying motor adaptation processes.