Sensorimotor strategy selection under time constraints in the presence of two motor targets with different values

Ryoji Onagawa,Kazutoshi Kudo

doi:10.1038/s41598-021-01584-w

Abstract

Goal-directed movements often require choosing an option from multiple potential goals under time constraints. However, there are limited studies on how humans change their time spent on decision-making and movement patterns according to time constraints. Here, we examined how sensorimotor strategies are selected under time constraints when the target values are uncertain. In the double-target condition, the values were uncertain until the movement onset and presented immediately afterwards. The behavior in this condition was compared to the single-target condition, in relation to time constraints and target-separation-angles. The results showed that the participants frequently used the choice-reaction even under tight time constraints, and their performance was consistently lower than that in the single-target condition. Additionally, in the double-target condition, differences in the movement trajectory depending on the time constraint and target-separation angle were confirmed. Specifically, the longer the time constraint, the higher the frequency of the intermediate behavior (to initiate movement toward the intermediate direction of two targets) or the change-of-mind behavior (to change the aiming target during movement). Furthermore, the smaller the target-separation angle, the higher the frequency of intermediate behavior, but the frequency of change-of-mind was not affected by the target-separation angle. These results suggest that the participants initiated the movement at an incomplete value judgment stage in some trials. Furthermore, they seemed to select a strategy to utilize the information obtained during the movement, taking into account the time constraints and target-separation angle. Our results show a consistent cognitive bias in choosing a higher value when multiple alternatives have different values. Additionally, we also suggest flexibility and adaptability in the movement patterns in response to time constraints.

Highlights

Goal-directed movements often require choosing an option from multiple potential goals under time constraints
The unique setting of the current task was that the target value was presented at the same time as the start signal of the task, and that a different time constraint was assigned in each trial
The current study mainly aimed to examine the effects of time constraints on decision-making and motor execution strategies

Summary

Introduction

Goal-directed movements often require choosing an option from multiple potential goals under time constraints. The smaller the targetseparation angle, the higher the frequency of intermediate behavior, but the frequency of changeof-mind was not affected by the target-separation angle These results suggest that the participants initiated the movement at an incomplete value judgment stage in some trials. By varying the rate of decrease in value from trial to trial and examining strategy switching, we found that participants changed their response strategies according to the rate, there was a bias toward over-preferring the choice-reaction strategy in situations where the gain decreased over time This bias may have stemmed from the difficulty of taking into account changes in value over time or from the known possible rewards for each target. It is necessary to consider whether a similar bias occurs in situations where there is high uncertainty about value

Results

Discussion

Conclusion