Prolonged reaction times help to eliminate residual errors in visuomotor adaptation

Abstract

20One persistent curiosity in visuomotor adaptation tasks is the fact that participants often 21 reach a learning asymptote well below full compensation. This incomplete asymptote has been 22 manipulating the planning time, we asked participants to continuously report their movement 34 aim. We show that emphasizing explicit re-aiming strategies also leads to full asymptotic 35 learning, supporting the idea that prolonged motor planning may involve a parametric rotation 36 of aiming direction whose premature termination yields incomplete asymptotic learning 37 (experiment 3). Findings from all experiments support the hypothesis that incomplete 38 adaptation is, in part, the result of an intrinsic speed-accuracy tradeoff, perhaps related to 39 cognitive strategies that require parametric attentional reorienting from the visual target to the 40 goal. 41 42

Competition between parallel sensorimotor learning systems

“…As expected, PT Limit participants dramatically reduced their reach latencies throughout the adaptation period, whereas No PT limit participants exhibited a sharp increase in movement preparation time after perturbation onset ( Fig. 3G), indicating explicit re-aiming 18,28,37,41,47 . Consistent with suppression of explicit strategy, learning proceeded more slowly and was less complete with the PT Limit ( Fig.…”

“…Current models suggest that this perturbation creates two distinct error sources. One error source is created by the deviation between the cursor and the target: a target error [17][18][19] . Notably, this target error (Fig.…”

“…3B, Subject A) and exhibited two characteristics that suggested the use of large explicit re-aiming angles: (1) their reach angle varied greatly from one cycle to the next 14,44,47 and (2) their movement preparation time ( Fig. 3C, Subject A) greatly increased upon onset of the perturbation 18,28,37,47 . On the other hand, Subject B reduced directional errors slowly and consistently ( Fig.…”

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

“…Larger rotation sizes may lead to more explicit re-aiming and, consequently, to a higher asymptote. However, it has also been proposed that the difference in asymptote does not arise from larger contributions of explicit re-aiming, but from the additional time subjects have when reporting, which allows for improved movement planning (Langsdorf, Maresch et al 2019).…”

“…Reports may also be contaminated by the observer paradox: asking subjects to produce subjective reports or to reflect on their own performance may influence the very processes that are being Methods matter monitored (Newell andShanks 2014, Timmermans andCleeremans 2015). Specifically, subjects may thus develop more explicit knowledge about the task by being repeatedly reminded about it whereas implicit adaptation remains unaffected (Langsdorf, Maresch et al 2019). Indirect methods may not confound measurement and awareness as fully as a direct measure, but there is still the danger that the experimental manipulation influences awareness.…”