The emergence of action-effect-related motor adaptation amidst outcome unpredictability.

Abstract

Previous research indicates that quick, repetitive actions (pinches, taps, button presses) are executed with smaller force when followed by predictable and salient action effects (tones, light flashes). It has been suggested that successive actions become gradually softer until an optimum is reached, which presumably reflects a balance between the ability to maintain a high probability of action success, and the reduction of exerted force to conserve energy. In the present experiments, we investigated whether this action-effect-related motor adaptation appeared when the arrival of the action effect was unpredictable. Young adult participants produced evenly spaced pinches (Experiment 1) or taps (Experiment 2), which resulted in a tone in 50% of the trials. The presence of the tone effect varied randomly from trial to trial, leading to action sequences with various tone-elicitation patterns. We have found that pinches and taps preceded by sequences of tone-eliciting actions were softer than actions preceded by sequences of toneabsent trials. In the case of pinches, actions were also modulated on the fly, with the current action being softer and briefer when a tone was elicited. Our results demonstrate that action effects can modulate subsequent and ongoing actions even when the arrival of these effects is unpredictable. Public Significance StatementThis study shows that salient action effects are used to optimize action execution when the action is performed repeatedly. This type of-potentially automatic-motor optimization allows one to quickly adapt to interactions offered by novel devices and tools.

Response Durations: A Flexible, No-Cost Tool for Psychological Science

“…Reducing the reliability of feedback signals, in turn, increases response force and duration. Such observations are consistent with the idea that participants use additional body-unrelated feedback for motor optimization, that is, for shifting the balance toward lesser motor effort (Karlovich & Graham, 1968; Varga et al, 2022).…”

Markov chains as a proxy for the predictive memory representations underlying mismatch negativity

“…A potential difference between match and mismatch of intended-action-effect and actually encountered sound in the preceding trial could manifest either or both in measures of motor behavior (e.g., speed, pressure), and brain activity (e.g., lateralized readiness potential, contingent negative variation). Indeed, such sequential effects have been studied to some extent (Pashler and Baylis, 1991;Notebaert and Soetens, 2003;10.3389/fnhum.2023.1249413 Frontiers in Human Neuroscience 14 frontiersin.org Roeber et al, 2009;Varga et al, 2022). While it is beyond the scope of this paper to discuss sound-to-action transitions in detail, the brief example given here stresses the point that the Markovian narrative may trigger hypotheses and aid in the development of respective experimental designs.…”