On the Relation between Visual Spatial Attention and Visual Field Asymmetries

1992 ◽  
Vol 44 (3) ◽  
pp. 529-555 ◽  
Author(s):  
T. A Mondor ◽  
M.P. Bryden
Keyword(s):  
Visual Field ◽  
Visual Attention ◽  
Visual Fields ◽  
Stimulus Onset ◽  
Right Visual Field ◽  
Structural Factors ◽  
Letter Identification ◽  
Functional Capabilities ◽  
Visual Spatial ◽  
The Right

In the typical visual laterality experiment, words and letters are more rapidly and accurately identified in the right visual field than in the left. However, while such studies usually control fixation, the deployment of visual attention is rarely restricted. The present studies investigated the influence of visual attention on the visual field asymmetries normally observed in single-letter identification and lexical decision tasks. Attention was controlled using a peripheral cue that provided advance knowledge of the location of the forthcoming stimulus. The time period between the onset of the cue and the onset of the stimulus (Stimulus Onset Asynchrony—SOA) was varied, such that the time available for attention to focus upon the location was controlled. At short SO As a right visual field advantage for identifying single letters and for making lexical decisions was apparent. However, at longer SOAs letters and words presented in the two visual fields were identified equally well. It is concluded that visual field advantages arise from an interaction of attentional and structural factors and that the attentional component in visual field asymmetries must be controlled in order to approximate more closely a true assessment of the relative functional capabilities of the right and left cerebral hemispheres.

Interocular torsional disparity and visual cortical development in the cat

1990 ◽  
Vol 64 (4) ◽  
pp. 1352-1360 ◽  
Author(s):  
M. R. Isley ◽  
D. C. Rogers-Ramachandran ◽  
P. G. Shinkman
Keyword(s):  
Visual Cortex ◽  
Visual Field ◽  
Ocular Dominance ◽  
Visual Fields ◽  
Receptive Fields ◽  
Right Visual Field ◽  
Orientation Columns ◽  
Areas 17 And 18 ◽  
The Right ◽  
Visual Cortical

1. The present experiments were designed to assess the effects of relatively large optically induced interocular torsional disparities on the developing kitten visual cortex. Kittens were reared with restricted visual experience. Three groups viewed a normal visual environment through goggles fitted with small prisms that introduced torsional disparities between the left and right eyes' visual fields, equal but opposite in the two eyes. Kittens in the +32 degrees goggle rearing condition experienced a 16 degrees counterclockwise rotation of the left visual field and a 16 degrees clockwise rotation of the right visual field; in the -32 degrees goggle condition the rotations were clockwise in the left eye and counterclockwise in the right. In the control (0 degree) goggle condition, the prisms did not rotate the visual fields. Three additional groups viewed high-contrast square-wave gratings through Polaroid filters arranged to provide a constant 32 degrees of interocular orientation disparity. 2. Recordings were made from neurons in visual cortex around the border of areas 17 and 18 in all kittens. Development of cortical ocular dominance columns was severely disrupted in all the experimental (rotated) rearing conditions. Most cells were classified in the extreme ocular dominance categories 1, 2, 6, and 7. Development of the system of orientation columns was also affected: among the relatively few cells with oriented receptive fields in both eyes, the distributions of interocular disparities in preferred stimulus orientation were centered near 0 degree but showed significantly larger variances than in the control condition.(ABSTRACT TRUNCATED AT 250 WORDS)

Vocal Reaction Times to Tachistoscopically Presented High- and Low-Frequency Verbs: Some Evidence for Selective Minor Hemisphere Linguistic Analysis

1988 ◽  
Vol 66 (3) ◽  
pp. 803-810 ◽  
Author(s):  
Michael P. Rastatter ◽  
Catherine Loren
Keyword(s):  
Visual Field ◽  
High Frequency ◽  
Right Hemisphere ◽  
Visual Fields ◽  
Reaction Times ◽  
Low Frequency ◽  
Normal Subjects ◽  
Right Visual Field ◽  
Intact Brain ◽  
The Right

The current study investigated the capacity of the right hemisphere to process verbs using a paradigm proven reliable for predicting differential, minor hemisphere lexical analysis in the normal, intact brain. Vocal reaction times of normal subjects were measured to unilaterally presented verbs of high and of low frequency. A significant interaction was noted between the stimulus items and visual fields. Post hoc tests showed that vocal reaction times to verbs of high frequency were significantly faster following right visual-field presentations (right hemisphere). No significant differences in vocal reaction time occurred between the two visual fields for the verbs of low frequency. Also, significant differences were observed between the two types of verbs following left visual-field presentation but not the right. These results were interpreted to suggest that right-hemispheric analysis was restricted to the verbs of high frequency in the presence of a dominant left hemisphere.

Effect of Learning on Hemispheric Dominance and Free Recall in a Single Subject

1972 ◽  
Vol 31 (1) ◽  
pp. 227-230 ◽  
Author(s):  
Lester C. Shine ◽  
Joseph Wiant ◽  
Frank Da Polito
Keyword(s):  
Free Recall ◽  
Visual Field ◽  
Analysis Of Variance ◽  
Field Condition ◽  
Left Visual Field ◽  
Visual Fields ◽  
Hemispheric Dominance ◽  
Right Visual Field ◽  
Single Subject ◽  
The Right

This experiment was designed to investigate the effect of learning on the free recall of letters presented tachistoscopically either to the left visual field, the right visual field, or identically and simultaneously to both visual fields. A modified Shine-Bower analysis of variance was used to analyze S's performance. The results indicate that initially, in accord with previous research, the right visual field is superior to the left visual field in performance, but that this superiority tends to reduce across trials and practically disappears in the later trials. Also, the right visual field condition is not appreciably better in performance than the condition with both visual fields.

Right Hemisphere Memory Bias Does Not Extend to Involuntary Memories for Negative Scenes

Perception ◽  
2021 ◽  
Vol 50 (1) ◽  
pp. 27-38
Author(s):  
Ella K. Moeck ◽  
Nicole A. Thomas ◽  
Melanie K. T. Takarangi
Keyword(s):  
Visual Field ◽  
Left Hemisphere ◽  
Right Hemisphere ◽  
Visual Fields ◽  
Memory Bias ◽  
Right Visual Field ◽  
Hemispheric Differences ◽  
Involuntary Memory ◽  
Involuntary Memories ◽  
The Right

Attention is unequally distributed across the visual field. Due to greater right than left hemisphere activation for visuospatial attention, people attend slightly more to the left than the right side. As a result, people voluntarily remember visual stimuli better when it first appears in the left than the right visual field. But does this effect—termed a right hemisphere memory bias—also enhance involuntary memory? We manipulated the presentation location of 100 highly negative images (chosen to increase the likelihood that participants would experience any involuntary memories) in three conditions: predominantly leftward (right hemisphere bias), predominantly rightward (left hemisphere bias), or equally in both visual fields (bilateral). We measured subsequent involuntary memories immediately and for 3 days after encoding. Contrary to predictions, biased hemispheric processing did not affect short- or long-term involuntary memory frequency or duration. Future research should measure hemispheric differences at retrieval, rather than just encoding.

Visual-Field Asymmetries in Letter Recognition: Evidence for Asymmetry in Early Visual Registration

1979 ◽  
Vol 49 (1) ◽  
pp. 183-191
Author(s):  
Colin Pitblado ◽  
Michael Petrides ◽  
Gary Riccio
Keyword(s):  
Visual Field ◽  
Recognition Accuracy ◽  
Visual Fields ◽  
Normal Subjects ◽  
Letter Recognition ◽  
Right Visual Field ◽  
Cerebral Asymmetry ◽  
Exposure Field ◽  
The Right

Two experiments on visual-field differences in tachistoscopic letter recognition are described. In the first, a bright pre-exposure field with a black fixation point was used, and the conventionally expected dominance of the right visual field was found. However, a large number of “blank” trials were observed, in which subjects completely failed to detect the presence of the flashed target. These “blanks” were themselves significantly asymmetric between visual fields, suggesting that asymmetry in early stimulus registration may play an unsuspected role in typical measures of cerebral asymmetry in recognition accuracy. This was confirmed in a second experiment in which use of dark pre-exposure fields eliminated “blanks” and led to higher over-all accuracy, with no visual-field differences. Implications for interpretation of laterality data with normal subjects are discussed.

Individual Variation in Directional Bias in Visual Perception

Perception ◽  
1983 ◽  
Vol 12 (1) ◽  
pp. 71-84 ◽  
Author(s):  
Marian Annett
Keyword(s):  
Visual Field ◽  
Visual Perception ◽  
Visual Fields ◽  
Total Sample ◽  
Right Visual Field ◽  
Reading Habits ◽  
Directional Bias ◽  
The Right ◽  
Lateral Bias ◽  
Onset Asynchrony

Directional biases in visual perception were examined for individual differences in sixty-five subjects on two tasks. One task required judgments of the onset asynchrony of pairs of dots presented at random, either one dot in each visual field, or both in the left visual field (LVF), or the right visual field (RVF). The second task required the recall of four letter strings presented randomly in either visual field. Dot-asynchrony judgments were influenced by two main biases: first, an outward from the centre bias in both visual fields, and second, a lateral bias which was significantly from left to right (L—R) in the total sample. A substantial minority of subjects were biased to judge the dots as occurring in right to left (R—L) order. Accuracy of letter report decreased fairly consistently from L—R in the RVF but varied in the LVF. Some subjects showed a L—R report gradient, some a R—L gradient, and some a U-shaped recall pattern. Significant correlations between measures of L—R and R—L biases on the two tasks show that the biases have some stable foundation. The findings suggest that there are directional biases affecting visual perception which are due neither to learned reading habits, nor to cerebral specialization of function.

Models of Response Time to Peripheral Stimuli

1974 ◽  
Vol 18 (5) ◽  
pp. 533-533
Author(s):  
D.S. Kochhar ◽  
T.M. Fraser
Keyword(s):  
Visual Field ◽  
Response Time ◽  
Visual Fields ◽  
Stimulus Location ◽  
Stimulus Size ◽  
Tracking Task ◽  
Right Visual Field ◽  
Simulated Driving ◽  
Left And Right ◽  
The Right

The variable contribution of peripherally presented stimuli in a A sensory motor task has been explored in terms of stimulus and environmental variables. A simulated driving task was chosen as being a representative compensatory tracking task. Empirical models have been developed using response surface methodology, statistical design and data collected on a simulator with a 240° wrap-around screen and projection systems very much like cinerama. In this research, seven factors were isolated for a study of their effects on detection latency to peripherally presented stimuli when the subject was ‘driving’. These factors were stimulus size (circular stimuli between 18′ and 60′), stimulus color (red, white and green), stimulus-background contrast (background luminance 1ft.L and stimulus luminance of 30, 60 and 90 ft.L), stimulus location along the horizontal (between ± 90°) and vertical meridians (between ± 26°), intensity of continuous white noise (between 52 and 100 dbA), and complexity of the continuous central tracking task measured in terms of the simulated driving speed. Three levels of each variable were selected in a 7 factor Box-Behnken design. Twenty undergraduates between the ages 19 and 26 participated in the experiment. It was found that, in this multivariable environment when all seven factors were simultaneously varied, the effects of noise, stimulus location in the visual field and stimulus size were the more important determinants of response latency. In addition, marked differences for the left and right visual fields were observed for the right-handed subject population. Four models have been developed: two for the left visual field, with and without the continuous central task (CCT), and two for the right visual field for the same conditions. The response was found to be of the form 1/Yr = f (xi); i= 1,2,… 7 for both the left and right visual fields in the presence of the CCT. In the absence of the CCT the model was of the form Yr = f (xr) for the left and 1/2 = f (xi) for the right visual field where Yr = response time in millisec. and Yr xi = variables in equations. Response curves have been presented to illustrate the variation of response time with each of the seven variables for regions where response time may be expected to be a minimum. The implications of these curves and the models on which they are based have been examined from the design point of view.

Visual Masking with Presentations in Same and opposite Visual Fields: Evidence for Contralateral Masking

1982 ◽  
Vol 55 (1) ◽  
pp. 131-140 ◽  
Author(s):  
Dennis P. Saccuzzo ◽  
Brad E. Michael ◽  
Robert Rowe
Keyword(s):  
Visual Field ◽  
Target Stimulus ◽  
Visual Masking ◽  
Visual Fields ◽  
Right Visual Field ◽  
Future Research ◽  
Backward Masking ◽  
Masking Stimulus ◽  
The Right ◽  
Contralateral Masking

Three experiments were conducted in a preliminary attempt to study the effects of presentations of an informational target stimulus to the right or left visual fields when the target was either preceded or followed by a non-informational masking stimulus and when the mask was presented to the same or opposite visual field of the target. Results indicated that masking was more effective in the same than in the opposite visual field but that masking of the opposite visual field was feasible for both forward and backward masking. Laterality effects were also found for forward and backward masking, with a modest advantage of the right visual field (left hemisphere) in both cases. Limitations of the data and directions for future research were discussed.

Parallel but Temporally Displaced Visual Half-Field Metacontrast Functions

1974 ◽  
Vol 26 (2) ◽  
pp. 258-265 ◽  
Author(s):  
Walter F. McKeever ◽  
Max Suberi
Keyword(s):  
Visual Field ◽  
Stimulus Onset Asynchrony ◽  
Left Visual Field ◽  
Right Hemisphere ◽  
Stimulus Onset ◽  
Right Visual Field ◽  
Field Function ◽  
Processing Delay ◽  
The Right ◽  
Onset Asynchrony

Using a classic letter-ring metacontrast paradigm, left and right visual field meta-contrast functions were separately determined. The parallel U-shaped recognition functions for both half-fields were found to interact differentially with stimulus onset asynchrony, the left visual field function being displaced by 13 ms toward longer test stimulus-masking stimulus separations. This result was consistent with the hypothesis of longer processing time requirements for verbal stimuli delivered to the right than to the left hemisphere. This indicates that the neural locus (loci) responsible for left visual field verbal processing delay is (are) capable of mediating metacontrast phenomena. It was tentatively concluded that a relative processing delay within the right hemisphere underlies the differing visual half-field metacontrast interaction with stimulus onset asynchrony.

scholarly journals Exploration of the Hemispheric Differences in Number Processing of the Brain

2012 ◽  
Vol 1 (2) ◽  
pp. 55-61
Author(s):  
Aaron Wyland Walters
Keyword(s):  
Reaction Time ◽  
Visual Field ◽  
Right Hemisphere ◽  
Visual Fields ◽  
Reaction Time Data ◽  
Right Visual Field ◽  
Hemispheric Differences ◽  
Time Data ◽  
Central Target ◽  
The Right

Abstract The current study explored how reaction time and accuracy differed in the left and right visual fields by altering various dot clusters in both number and organization. Researchers have hypothesized that the left hemisphere uses counting to judge small, disorganized clusters of objects accurately and that the right hemisphere uses estimation to judge clusters organized in geometric shape accurately. The current study tested both visual fields of participant’s with organized and unorganized clusters of dots. Dots were clustered between 3 and 12. The clusters were presented on separate sides of a computer screen to analyze visual field differences in counting and estimation. A central target was presented on the screen to maintain central focus for the visual fields. Data from 40 participants (30 men, 10 women) from a small liberal arts college indicated that when clusters reached between 7 and 8 dots, organization in the right visual field created inaccuracy in judgment. Reaction time data indicated that as number level increased, reaction time slowed. Reaction time data also showed that organization slowed reaction times in both visual fields. These data indicated that different numerical judgment abilities do exist within the hemispheres.

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