The Effect of Gaze Position on Reaching Movements in an Obstacle Avoidance Task

Ross, Alasdair Iain; Schenk, Thomas; Hesse, Constanze

doi:10.1371/journal.pone.0144193

Cited by 6 publications

(9 citation statements)

References 49 publications

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“…The asymmetry in increasing safety margins between rightward and leftward 517 movements was unexpected. To explain this pattern of results it is noteworthy to emphasize that the 518 increase in trajectory curvature due to removing the visual feedback is much less for rightward 519 compared to leftward passes (the comparison between dotted line and solid line in Figure 6B), which is 520 also in accordance with previous findings ( Similarly, Ross et al (2015) observed that varying the fixation while the visual feedback was available 533 caused participants to veer away from the fixated obstacle as opposed to free viewing or central 534…”

Section: Adapted Behavior Resulted In the Same Collision Rate For Difsupporting

confidence: 86%

Reaching around obstacles accounts for uncertainty in coordinate transformations

Khoozani

Voudouris

Blohm

et al. 2019

Preprint

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AbstractWhen reaching to a visual target, humans need to transform the spatial target representation into the coordinate system of their moving arm. It has been shown that increased uncertainty in such coordinate transformations, for instance when the head is rolled toward one shoulder, leads to higher movement variability and influence movement decisions. However, it is unknown whether the brain incorporates such added variability in planning and executing movements. We designed an obstacle avoidance task in which participants had to reach with or without visual feedback of the hand to a visual target while avoiding collisions with an obstacle. We varied coordinate transformation uncertainty by varying head roll (straight, 30° clockwise and 30° counterclockwise). In agreement with previous studies, we observed that the reaching variability increased when the head was tilted. Indeed, head roll did not influence the number of collisions during reaching compared to the head straight condition, but it did systematically change the obstacle avoidance behavior. Participants changed the preferred direction of passing the obstacle and increased the safety margins indicated by stronger movement curvature. These results suggest that the brain takes the added movement variability during head roll into account and compensates for it by adjusting the reaching trajectories.

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Section: Adapted Behavior Resulted In the Same Collision Rate For Difsupporting

confidence: 86%

Reaching around obstacles accounts for uncertainty in coordinate transformations

Khoozani

Voudouris

Blohm

et al. 2019

Preprint

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“…Eye-movements resulting in voltage changes of about 10-20 microVolts could be reliably identified and correspond to eye-movements of about 2° of visual angle (depending on skin condition, tiredness, etc. of participants, see Ross, Schenk, & Hesse, 2015 for similar procedure). Eye-movements were re-calibrated after every block for each participant.…”

Section: Set-upmentioning

confidence: 99%

Shared attention for action selection and action monitoring in goal-directed reaching

Mahon

Bendžiūtė

Hesse

et al. 2018

Psychological Research

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Dual-task studies have shown higher sensitivity for stimuli presented at the targets of upcoming actions. We examined whether attention is directed to action targets for the purpose of action selection, or if attention is directed to these locations because they are expected to provide feedback about movement outcomes. In our experiment, endpoint accuracy feedback was spatially separated from the action targets to determine whether attention would be allocated to (a) the action targets, (b) the expected source of feedback, or (c) to both locations. Participants reached towards a location indicated by an arrow while identifying a discrimination target that could appear in any one of eight possible locations. Discrimination target accuracy was used as a measure of attention allocation. Participants were unable to see their hand during reaching and were provided with a small monetary reward for each accurate movement. Discrimination target accuracy was best at action targets but was also enhanced at the spatially separated feedback locations. Separating feedback from the reaching targets did not diminish discrimination accuracy at the movement targets but did result in delayed movement initiation and reduced reaching accuracy, relative to when feedback was presented at the reaching target. The results suggest attention is required for both action planning and monitoring movement outcomes. Dividing attention between these functions negatively impacts action performance.

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“…The general idea that the fixation point plays an important role in the determination of the prehensile movement patterns has support from a study conducted by Ross, Schenk and Hesse [ 27 ]. Ross, Schenk and Hesse found that obstacle avoidance behaviour was moderated by fixation position when participants were required to move their hands through a gap between two obstacles into a target area.…”

Section: Discussionmentioning

confidence: 99%

Predicting the duration of reach-to-grasp movements to objects with asymmetric contact surfaces

Coats¹,

Holt²,

Bingham³

et al. 2018

PLoS ONE

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The duration of reach-to-grasp movements is influenced by the size of the contact surfaces, such that grasping objects with smaller contact surface areas takes longer. But what is the influence of asymmetric contact surfaces? In Experiment 1a, participants reached-to-lift wooden blocks off a table top, with the contact locations for the thumb and index finger varying in surface size. The time taken to lift the block was driven primarily by the thumb contact surface, which showed a larger effect size for the dependent variable of movement duration than the index finger’s contact surface. In Experiment 1b participants reached-to-grasp (but not lift) the blocks. The same effect was found with duration being largely driven by contact surface size for the thumb. Experiment 2 tested whether this finding generalised to movements towards conical frusta grasped in a different plane mounted off the table top. Experiment 2 showed that movement duration again was dictated primarily by the size of the thumb’s contact surface. The thumb contact surface was the visible surface in experiments 1 and 2 so Experiment 3 explored grasping when the index finger’s contact surface was visible (participants grasped the frusta with the index finger at the top). An interaction between thumb and finger surface size was now found to determine movement duration. These findings provide the first empirical report of the impact of asymmetric contact surfaces on prehension, and may have implications for scientists who wish to model reach-to-grasp behaviours.

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The Effect of Gaze Position on Reaching Movements in an Obstacle Avoidance Task

Cited by 6 publications

References 49 publications

Reaching around obstacles accounts for uncertainty in coordinate transformations

Reaching around obstacles accounts for uncertainty in coordinate transformations

Shared attention for action selection and action monitoring in goal-directed reaching

Predicting the duration of reach-to-grasp movements to objects with asymmetric contact surfaces

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