‘The last channel’: vision at the temporal margin of the field

The human visual field, on the temporal side, extends to at least 90° from the line of sight. Using a two-alternative forced-choice procedure in which observers are asked to report the direction of motion of a Gabor patch, and taking precautions to exclude unconscious eye movements in the direction of the stimulus, we show that the limiting eccentricity of image-forming vision can be established with precision. There are large, but reliable, individual differences in the limiting eccentricity. The limiting eccentricity exhibits a dependence on log contrast; but it is not reduced when the modulation visible to the rods is attenuated, a result compatible with the histological evidence that the outermost part of the retina exhibits a high density of cones. Our working hypothesis is that only one type of neural channel is present in the far periphery of the retina, a channel that responds to temporally modulated stimuli of low spatial frequency and that is directionally selective.

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Reaction Time to Gratings: A Re-Examination

Perception ◽

10.1068/v96l0608 ◽

1996 ◽

Vol 25 (1_suppl) ◽

pp. 16-16 ◽

Cited By ~ 2

Author(s):

C Bonnet ◽

J P Thomas ◽

P Fagerholm

Keyword(s):

Reaction Time ◽

Spatial Frequency ◽

Window Size ◽

Vertical Axis ◽

Grating Period ◽

Sinusoidal Grating ◽

Choice Procedure ◽

Frequency Detection ◽

Forced Choice Procedure ◽

Number Of Cycles

We have examined the relationship between the reaction time for detecting a sinusoidal grating stimulus and the stimulus variables of spatial frequency, contrast, window size, and uncertainty with respect to spatial frequency. Detection was measured in a two-alternative spatial-forced-choice procedure. The stimuli were horizontal cosine gratings windowed spatially by two-dimensional Gaussians. Spatial frequency was varied from 0.7 to 6.5 cycles deg−1 and contrast was varied from 0.054 to 0.673. The standard deviation of the Gaussian window was fixed in some conditions and the number of cycles presented in each window covaried with spatial frequency. In other conditions, window size was varied, along the vertical axis only, to hold the number of cycles constant. Contrasts were always randomly intermixed, but frequencies were intermixed in some conditions and blocked in others. We confirm previous findings that reaction time increases as spatial frequency increases and decreases as contrast increases. We also confirm and extend the proposal of Rudd that reaction time closely approximates a single function of the product of contrast and the square of the grating period. We consider the implications of these findings for the nature of the physiological mechanisms which govern reaction time.

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The Sensitivity of Binocular Rivalry Suppression to Changes in Orientation Assessed by Reaction-Time and Forced-Choice Techniques

Perception ◽

10.1068/p100283 ◽

1981 ◽

Vol 10 (3) ◽

pp. 283-293 ◽

Cited By ~ 17

Author(s):

Robert P O'Shea ◽

Boris Crassini

Keyword(s):

Reaction Time ◽

Spatial Frequency ◽

Binocular Rivalry ◽

Luminance Contrast ◽

Forced Choice ◽

Field Size ◽

Correct Performance ◽

Orientation Change ◽

Choice Procedure ◽

Forced Choice Procedure

Binocular rivalry was induced between two orthogonal square-wave gratings of the same spatial frequency, luminance, contrast, and field size, presented dichoptically. One of the gratings could be instantly replaced by a third grating differing only in orientation. In one experiment subjects were required to respond as soon as an orientation change was noticed, and to withold response to catch trials (no orientation change). When orientation changes were made to the visible grating, reaction time was found to be a U-shaped function of the magnitude of orientation change. When orientation changes were made to the grating undergoing binocular-rivalry suppression, an overall increase in reaction time was found with the increase being greater for large orientation changes (an asymmetrical U-shaped function). In another experiment subjects were required to detect the direction of a change in orientation in a two-alternative forced-choice procedure. Thresholds were thus obtained for 75% correct performance. It was found that thresholds for orientation changes made to the visible and invisible fields were identical from 20° to 70° orientation change. Outside this range thresholds were higher when orientation changes were made to the field suppressed by binocular rivalry. It is argued that the orientation functions obtained in the two experiments may represent incomplete suppression of either form or transient information during binocular rivalry.

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Meridional Differences in Temporal Resolution

Perception ◽

10.1068/p110025 ◽

1982 ◽

Vol 11 (1) ◽

pp. 25-34 ◽

Cited By ~ 7

Author(s):

Barry D Schwartz ◽

Daniel K Winstead ◽

James G May

Keyword(s):

Spatial Frequency ◽

Temporal Resolution ◽

Oblique Effect ◽

Channel Activity ◽

Flash Duration ◽

Choice Procedure ◽

Stimulus Parameters ◽

Transient Activity ◽

Transient Channel ◽

Forced Choice Procedure

Previous investigations of temporal resolution have shown that performance is influenced by a number of stimulus parameters. The interstimulus interval needed for accurate two-pulse discrimination has been shown to (i) decrease monotonically with flash duration, luminance, and contrast; and (ii) increase monotonically with the spatial frequency of the target. A signal-detectability two-alternative forced-choice procedure was employed to reexamine the effects of spatial frequency on temporal resolution. Also assessed was the effect of grating orientation on such performance. The results confirm that temporal resolution declines with increases in spatial frequency. Furthermore, temporal resolution was significantly lower when oblique, as opposed to vertical, grating targets were used. This ‘oblique effect’ in temporal resolution was observed only with the highest-spatial-frequency target (15 cycles deg−1), and not with stimuli of lower spatial frequency (0·9 and 3·8 cycles deg−1). These findings suggest that stimulus parameters which elicit greater transient channel activity, as opposed to sustained channel activity, enhance temporal resolution. When transient activity is at a minimum, meridional differences in temporal resolution are likely to be attributable to sustained channel activity.

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Visual asymmetries during face encoding Increased dwell time and fixations in the upper and left hemifields

10.31234/osf.io/pc649 ◽

2018 ◽

Author(s):

Fatima Maria Felisberti

Keyword(s):

Face Recognition ◽

Eye Movements ◽

Visual Field ◽

Face Processing ◽

Dwell Time ◽

The Other ◽

Environmental Cues ◽

Reading Habits ◽

The Right

Visual field asymmetries (VFA) in the encoding of groups rather than individual faces has been rarely investigated. Here, eye movements (dwell time (DT) and fixations (Fix)) were recorded during the encoding of three groups of four faces tagged with cheating, cooperative, or neutral behaviours. Faces in each of the three groups were placed in the upper left (UL), upper right (UR), lower left (LL), or lower right (LR) quadrants. Face recognition was equally high in the three groups. In contrast, the proportion of DT and Fix were higher for faces in the left than the right hemifield and in the upper rather than the lower hemifield. The overall time spent looking at the UL was higher than in the other quadrants. The findings are relevant to the understanding of VFA in face processing, especially groups of faces, and might be linked to environmental cues and/or reading habits.

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The relationship between eye movements and subsequent recognition: Evidence from individual differences and amnesia

Cortex ◽

10.1016/j.cortex.2016.10.007 ◽

2016 ◽

Vol 85 ◽

pp. 182-193 ◽

Cited By ~ 26

Author(s):

Rosanna K. Olsen ◽

Vinoja Sebanayagam ◽

Yunjo Lee ◽

Morris Moscovitch ◽

Cheryl L. Grady ◽

...

Keyword(s):

Individual Differences ◽

Eye Movements ◽

The Relationship

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Visual Field Accuracy and Eye Movement Direction: A Child's Eye View

Perceptual and Motor Skills ◽

10.1177/003151258005000250 ◽

1980 ◽

Vol 50 (2) ◽

pp. 631-636

Author(s):

Evans Mandes

Keyword(s):

Eye Movements ◽

Visual Field ◽

Eye Movement ◽

Visual Fields ◽

Movement Direction

Post-exposural eye movements were studied in 32 adults and 24 7-yr.-old children. Stimuli were binary figures exposed tachistoscopically in both visual fields simultaneously. The data showed significant correlations between direction of eye movement and locus of recognition for both children and adults. No significant differences were found in frequencies of eye movements of children and adults. The data are interpreted in terms of the facilitative effects of post-exposural eye movements upon perception for both groups.

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High Ripple-Density Resolution for Discriminating Between Rippled and Nonrippled Signals: Effect of Temporal Processing or Combination Products?

Trends in Hearing ◽

10.1177/23312165211010163 ◽

2021 ◽

Vol 25 ◽

pp. 233121652110101

Author(s):

Dmitry I. Nechaev ◽

Olga N. Milekhina ◽

Marina S. Tomozova ◽

Alexander Y. Supin

Keyword(s):

Low Frequency ◽

Noise Signal ◽

Density Variation ◽

Choice Procedure ◽

Masker Level ◽

Reference Signals ◽

Forced Choice Procedure ◽

The Mean ◽

Density Resolution

The goal of the study was to investigate the role of combination products in the higher ripple-density resolution estimates obtained by discrimination between a spectrally rippled and a nonrippled noise signal than that obtained by discrimination between two rippled signals. To attain this goal, a noise band was used to mask the frequency band of expected low-frequency combination products. A three-alternative forced-choice procedure with adaptive ripple-density variation was used. The mean background (unmasked) ripple-density resolution was 9.8 ripples/oct for rippled reference signals and 21.8 ripples/oct for nonrippled reference signals. Low-frequency maskers reduced the ripple-density resolution. For masker levels from −10 to 10 dB re. signal, the ripple-density resolution for nonrippled reference signals was approximately twice as high as that for rippled reference signals. At a masker level as high as 20 dB re. signal, the ripple-density resolution decreased in both discrimination tasks. This result leads to the conclusion that low-frequency combination products are not responsible for the task-dependent difference in ripple-density resolution estimates.

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Comprehension and Eye Movements in the Processing of Subject- and Object-Relative Clauses: Evidence from Dyslexia and Individual Differences

Brain Sciences ◽

10.3390/brainsci11070915 ◽

2021 ◽

Vol 11 (7) ◽

pp. 915

Author(s):

Marianna Stella ◽

Paul E. Engelhardt

Keyword(s):

Working Memory ◽

Individual Differences ◽

Eye Movements ◽

Relative Clauses ◽

Sentence Type ◽

Main Effect ◽

Subject And Object ◽

The Subject ◽

Processing Difficulty ◽

Object Relative

In this study, we examined eye movements and comprehension in sentences containing a relative clause. To date, few studies have focused on syntactic processing in dyslexia and so one goal of the study is to contribute to this gap in the experimental literature. A second goal is to contribute to theoretical psycholinguistic debate concerning the cause and the location of the processing difficulty associated with object-relative clauses. We compared dyslexic readers (n = 50) to a group of non-dyslexic controls (n = 50). We also assessed two key individual differences variables (working memory and verbal intelligence), which have been theorised to impact reading times and comprehension of subject- and object-relative clauses. The results showed that dyslexics and controls had similar comprehension accuracy. However, reading times showed participants with dyslexia spent significantly longer reading the sentences compared to controls (i.e., a main effect of dyslexia). In general, sentence type did not interact with dyslexia status. With respect to individual differences and the theoretical debate, we found that processing difficulty between the subject and object relatives was no longer significant when individual differences in working memory were controlled. Thus, our findings support theories, which assume that working memory demands are responsible for the processing difficulty incurred by (1) individuals with dyslexia and (2) object-relative clauses as compared to subject relative clauses.

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Vision as oculomotor reward: cognitive contributions to the dynamic control of saccadic eye movements

Cognitive Neurodynamics ◽

10.1007/s11571-020-09661-y ◽

2021 ◽

Author(s):

Christian Wolf ◽

Markus Lappe

Keyword(s):

Eye Movements ◽

Visual Field ◽

Visual System ◽

Dynamic Control ◽

Saccadic Eye Movements ◽

Saccade Target ◽

Cognitive Mechanisms ◽

Foveal Vision ◽

Subsequent Behavior ◽

High Level

AbstractHumans and other primates are equipped with a foveated visual system. As a consequence, we reorient our fovea to objects and targets in the visual field that are conspicuous or that we consider relevant or worth looking at. These reorientations are achieved by means of saccadic eye movements. Where we saccade to depends on various low-level factors such as a targets’ luminance but also crucially on high-level factors like the expected reward or a targets’ relevance for perception and subsequent behavior. Here, we review recent findings how the control of saccadic eye movements is influenced by higher-level cognitive processes. We first describe the pathways by which cognitive contributions can influence the neural oculomotor circuit. Second, we summarize what saccade parameters reveal about cognitive mechanisms, particularly saccade latencies, saccade kinematics and changes in saccade gain. Finally, we review findings on what renders a saccade target valuable, as reflected in oculomotor behavior. We emphasize that foveal vision of the target after the saccade can constitute an internal reward for the visual system and that this is reflected in oculomotor dynamics that serve to quickly and accurately provide detailed foveal vision of relevant targets in the visual field.

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Spatial frequency channels derived from individual differences

Vision Research ◽

10.1016/j.visres.2005.01.015 ◽

2005 ◽

Vol 45 (21) ◽

pp. 2723-2727 ◽

Cited By ~ 14

Author(s):

William A. Simpson ◽

Sharon M. McFadden

Keyword(s):

Individual Differences ◽

Spatial Frequency

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