Gaze when reaching to grasp a glass

Voudouris, Dimitris; Smeets, Jeroen B. J.; Fiehler, Katja; Brenner, Eli

doi:10.1167/18.8.16

Cited by 17 publications

(12 citation statements)

References 28 publications

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“…This coincides with the transition from the directing fixation to visually checking the lifting action. This is in line with observations by Voudouris et al (2018), who noted that people may fixate higher when grasping and lifting an object to direct their gaze to where the object will be in the future.…”

Section: Discussionsupporting

confidence: 92%

On the Visuomotor Behavior of Amputees and Able-Bodied People During Grasping

Gregori¹,

Cognolato²,

Saetta³

et al. 2019

Front. Bioeng. Biotechnol.

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Visual attention is often predictive for future actions in humans. In manipulation tasks, the eyes tend to fixate an object of interest even before the reach-to-grasp is initiated. Some recent studies have proposed to exploit this anticipatory gaze behavior to improve the control of dexterous upper limb prostheses. This requires a detailed understanding of visuomotor coordination to determine in which temporal window gaze may provide helpful information. In this paper, we verify and quantify the gaze and motor behavior of 14 transradial amputees who were asked to grasp and manipulate common household objects with their missing limb. For comparison, we also include data from 30 able-bodied subjects who executed the same protocol with their right arm. The dataset contains gaze, first person video, angular velocities of the head, and electromyography and accelerometry of the forearm. To analyze the large amount of video, we developed a procedure based on recent deep learning methods to automatically detect and segment all objects of interest. This allowed us to accurately determine the pixel distances between the gaze point, the target object, and the limb in each individual frame. Our analysis shows a clear coordination between the eyes and the limb in the reach-to-grasp phase, confirming that both intact and amputated subjects precede the grasp with their eyes by more than 500 ms. Furthermore, we note that the gaze behavior of amputees was remarkably similar to that of the able-bodied control group, despite their inability to physically manipulate the objects.

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Section: Discussionsupporting

confidence: 92%

On the Visuomotor Behavior of Amputees and Able-Bodied People During Grasping

Gregori¹,

Cognolato²,

Saetta³

et al. 2019

Front. Bioeng. Biotechnol.

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show abstract

“…The bases of the paraboloids always subtended 6.58 of visual angle. By keeping the fixation point near the thumb's contact point, we mimicked the natural fixation patterns obtained when using a precision grip to grasp objects at eye level (Vodouris, Smeets, Fiehler, & Brenner, 2018). Stereoscopic presentation was achieved with a frame interlacing technique in conjunction with liquid-crystal goggles synchronized to the frame rate.…”

Section: Apparatusmentioning

confidence: 99%

Depth cue reweighting requires altered correlations with haptic feedback

Cesanek

Domini

2019

Journal of Vision

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Depth cue reweighting is a feedback-driven learning process that modifies the relative influences of different sources of three-dimensional shape information in perceptual judgments and or motor planning. In this study, we investigated the mechanism supporting reweighting of stereo and texture information by manipulating the haptic feedback obtained during a series of grasping movements. At the end of each grasp, the fingers closed down on a physical object that was consistent with one of the two cues, depending on the condition. Previous studies have shown that this style of visuomotor training leads to cue reweighting for perceptual judgments, but the time course has never been documented for a single training session, and many questions remain regarding the underlying mechanism, such as the pattern of feedback signals required to drive reweighting. We address these issues in two experiments, finding short-term changes in the motor response consistent with cue reweighting: the slope of the grip aperture with respect to the reliable cue increased, whereas the slope with respect to the unreliable cue decreased. Critically, Experiment 2 shows that slope changes do not occur when one of the cues is rendered with a constant bias; the grip aperture simply becomes uniformly larger or smaller. Our findings support a model of cue reweighting driven by altered correlations between haptic feedback and individual cues, rather than simple mismatches, which can be resolved by other mechanisms such as sensorimotor adaptation or cue recalibration.

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“…Thus, it is likely that retinal information is normally used to guide the digits to their goals (Ca´mara et al, 2018). Where the eyes are oriented for guiding the digits to their goals is presumably determined by where one expects it to be useful to have a high retinal resolution (Voudouris et al, 2018), rather than by it being easier to move a digit to where one is looking (Neggers & Bekkering, 2001). We conclude that people rely on vision to direct their gaze, even when directing gaze to their own finger.…”

Section: Discussionmentioning

confidence: 76%

Looking Precisely at Your Fingertip Requires Visual Guidance of Gaze

et al. 2020

Self Cite

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People often look at objects that they are holding in their hands. It is therefore reasonable to expect them to be able to direct their gaze precisely with respect to their fingers. However, we know that people make reproducible idiosyncratic errors of up to a few centimetres when they try to align a visible cursor to their own finger hidden below a surface. To find out whether they also make idiosyncratic errors when they try to look at their finger, we asked participants to hold their finger in front of their head in the dark, and look at it. Participants made idiosyncratic errors of a similar magnitude to those previously found when matching a visual cursor to their hidden finger. This shows that proprioceptive position sense of finger and gaze are not aligned, suggesting that people rely on vision to guide their gaze to their own finger.

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Gaze when reaching to grasp a glass

Cited by 17 publications

References 28 publications

On the Visuomotor Behavior of Amputees and Able-Bodied People During Grasping

On the Visuomotor Behavior of Amputees and Able-Bodied People During Grasping

Depth cue reweighting requires altered correlations with haptic feedback

Looking Precisely at Your Fingertip Requires Visual Guidance of Gaze

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