Memory and prediction in natural gaze control

In addition to stimulus properties and task factors, memory is an important determinant of the allocation of attention and gaze in the natural world. One way that the role of memory is revealed is by predictive eye movements. Both smooth pursuit and saccadic eye movements demonstrate predictive effects based on previous experience. We have previously shown that unskilled subjects make highly accurate predictive saccades to the anticipated location of a ball prior to a bounce in a virtual racquetball setting. In this experiment, we examined this predictive behaviour. We asked whether the period after the bounce provides subjects with visual information about the ball trajectory that is used to programme the pursuit movement initiated when the ball passes through the fixation point. We occluded a 100 ms period of the ball's trajectory immediately after the bounce, and found very little effect on the subsequent pursuit movement. Subjects did not appear to modify their strategy to prolong the fixation. Neither were we able to find an effect on interception performance. Thus, it is possible that the occluded trajectory information is not critical for subsequent pursuit, and subjects may use an estimate of the ball's trajectory to programme pursuit. These results provide further support for the role of memory in eye movements.

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Regarding Scenes

Current Directions in Psychological Science ◽

10.1111/j.1467-8721.2007.00507.x ◽

2007 ◽

Vol 16 (4) ◽

pp. 219-222 ◽

Cited By ~ 138

Author(s):

John M. Henderson

Keyword(s):

Eye Movements ◽

Real Time ◽

Real World ◽

Visual Information ◽

Scene Perception ◽

Saccadic Eye Movements ◽

Gaze Direction ◽

Behavioral Activity ◽

Gaze Control ◽

Gaze Stability

When we view the visual world, our eyes flit from one location to another about three times each second. These frequent changes in gaze direction result from very fast saccadic eye movements. Useful visual information is acquired only during fixations, periods of relative gaze stability. Gaze control is defined as the process of directing fixation through a scene in real time in the service of ongoing perceptual, cognitive, and behavioral activity. This article discusses current approaches and new empirical findings that are allowing investigators to unravel how human gaze control operates during active real-world scene perception.

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Faculty Opinions recommendation of Head-free gaze shifts provide further insights into the role of the medial cerebellum in the control of primate saccadic eye movements.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.4961957.4893055 ◽

2010 ◽

Author(s):

Raj Gandhi

Keyword(s):

Eye Movements ◽

Saccadic Eye Movements ◽

Gaze Shifts

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The role of action intentionality and effector in the subjective expansion of temporal duration after saccadic eye movements

Scientific Reports ◽

10.1038/s41598-020-73830-6 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

David Melcher ◽

Devpriya Kumar ◽

Narayanan Srinivasan

Keyword(s):

Eye Movements ◽

Visual Processing ◽

Saccadic Eye Movements ◽

Intentional Binding ◽

Opposite Pattern ◽

Motor Action ◽

Saccade Onset ◽

Backward Shift ◽

The Moment

Abstract Visual perception is based on periods of stable fixation separated by saccadic eye movements. Although naive perception seems stable (in space) and continuous (in time), laboratory studies have demonstrated that events presented around the time of saccades are misperceived spatially and temporally. Saccadic chronostasis, the “stopped clock illusion”, represents one such temporal distortion in which the movement of the clock hand after the saccade is perceived as lasting longer than usual. Multiple explanations for chronostasis have been proposed including action-backdating, temporal binding of the action towards the moment of its effect (“intentional binding”) and post-saccadic temporal dilation. The current study aimed to resolve this debate by using different types of action (keypress vs saccade) and varying the intentionality of the action. We measured both perceived onset of the motor action and perceived onset of an auditory tone presented at different delays after the keypress/saccade. The results showed intentional binding for the keypress action, with perceived motor onset shifted forwards in time and the time of the tone shifted backwards. Saccades resulted in the opposite pattern, showing temporal expansion rather than compression, especially with cued saccades. The temporal illusion was modulated by intentionality of the movement. Our findings suggest that saccadic chronostasis is not solely dependent on a backward shift in perceived saccade onset, but instead reflects a temporal dilation. This percept of an effectively “longer” period at the beginning of a new fixation may reflect the pattern of suppressed, and then enhanced, visual processing around the time of saccades.

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The role of fixation disengagement in the parallel programming of sequences of saccades

Experimental Brain Research ◽

10.1007/s00221-019-05641-9 ◽

2019 ◽

Vol 237 (11) ◽

pp. 3033-3045

Author(s):

Eugene McSorley ◽

Iain D. Gilchrist ◽

Rachel McCloy

Keyword(s):

Eye Movements ◽

Parallel Programming ◽

Response Times ◽

Saccadic Eye Movements ◽

Gap Effect ◽

Task Completion ◽

Published Data ◽

Trial Duration ◽

Visual Tasks

Abstract One of the core mechanisms involved in the control of saccade responses to selected target stimuli is the disengagement from the current fixation location, so that the next saccade can be executed. To carry out everyday visual tasks, we make multiple eye movements that can be programmed in parallel. However, the role of disengagement in the parallel programming of saccades has not been examined. It is well established that the need for disengagement slows down saccadic response time. This may be important in allowing the system to program accurate eye movements and have a role to play in the control of multiple eye movements but as yet this remains untested. Here, we report two experiments that seek to examine whether fixation disengagement reduces saccade latencies when the task completion demands multiple saccade responses. A saccade contingent paradigm was employed and participants were asked to execute saccadic eye movements to a series of seven targets while manipulating when these targets were shown. This both promotes fixation disengagement and controls the extent that parallel programming can occur. We found that trial duration decreased as more targets were made available prior to fixation: this was a result both of a reduction in the number of saccades being executed and in their saccade latencies. This supports the view that even when fixation disengagement is not required, parallel programming of multiple sequential saccadic eye movements is still present. By comparison with previous published data, we demonstrate a substantial speeded of response times in these condition (“a gap effect”) and that parallel programming is attenuated in these conditions.

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Exploring Young Children’s Use of Illustrations in a Picturebook

Language and Literacy ◽

10.20360/g2630c ◽

2015 ◽

Vol 17 (1) ◽

pp. 42 ◽

Cited By ~ 4

Author(s):

Karen M. Feathers ◽

Poonam Arya

Keyword(s):

Eye Movements ◽

Eye Tracking ◽

Oral Reading ◽

Visual Information ◽

Text Processing ◽

Third Grade

Using analysis of oral reading and eye movements, this study examined how third grade children used visual information as they orally read either the original or the adapted version of a picturebook. Eye tracking was examined to identify when and why students focused on images as well as what they looked at in the images. Results document children’s deliberate use of images and point to the important role of images in text processing. The content of images, availability and placement of text and images on a page, and children’s personal strategies affected the use of images.

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Role of Eye Movements in the Retinal Code for a Size Discrimination Task

Journal of Neurophysiology ◽

10.1152/jn.00395.2007 ◽

2007 ◽

Vol 98 (3) ◽

pp. 1380-1391 ◽

Cited By ~ 30

Author(s):

Ronen Segev ◽

Elad Schneidman ◽

Joe Goodhouse ◽

Michael J. Berry

Keyword(s):

Eye Movements ◽

Visual Information ◽

Ganglion Cells ◽

Multielectrode Array ◽

Retinal Ganglion ◽

Size Discrimination ◽

Fixational Eye Movements ◽

Stationary Objects ◽

A Minor

The concerted action of saccades and fixational eye movements are crucial for seeing stationary objects in the visual world. We studied how these eye movements contribute to retinal coding of visual information using the archer fish as a model system. We quantified the animal's ability to distinguish among objects of different sizes and measured its eye movements. We recorded from populations of retinal ganglion cells with a multielectrode array, while presenting visual stimuli matched to the behavioral task. We found that the beginning of fixation, namely the time immediately after the saccade, provided the most visual information about object size, with fixational eye movements, which consist of tremor and drift in the archer fish, yielding only a minor contribution. A simple decoder that combined information from ≤15 ganglion cells could account for the behavior. Our results support the view that saccades impose not just difficulties for the visual system, but also an opportunity for the retina to encode high quality “snapshots” of the environment.

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