Visual field differences in recognizing letters

Worrall, Norman; Coles, Peter

doi:10.3758/bf03198698

Cited by 20 publications

(7 citation statements)

References 26 publications

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“…Field position of the target was also investigated, and main effects were found for laterality, verticality, and distance. The tendency for all groups to perform better when the target was located in the RVF supports the usual finding that the left hemisphere is superior in processing verbal (including letter) stimuli (e.g., Worral & Coles, 1976). Subjects also performed better when the target was located in the top half than in the bottom half of the display and when the target was closer to the center (proximal) than when it was more peripheral (distal).…”

Section: Discussionsupporting

confidence: 83%

Span of apprehension in schizophrenic patients as a function of distractor masking and laterality.

Elkins¹,

Cromwell²,

Asarnow³

1992

Journal of Abnormal Psychology

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Twenty schizophrenic patients, 10 depressed control patients, and 20 normal control subjects were compared in a forced-choice, target-detection method for assessing the span of apprehension. The detection task required the subject to report which of 2 target letters was presented among 7 other (distractor) letters. Performance accuracy was examined as a function of target location and whether the distractor letters were masked after their presentation. The backward masking of the distractors improved target-detection accuracy of both control groups but reduced accuracy of the schizophrenic group. In addition, schizophrenics performed particularly poorly on targets located in the left half or lower half of the display. These results suggest that response to the masking of distractors may be a new index of attentional shortcoming in schizophrenia. Various theoretical explanations for the target location findings are also discussed.

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Section: Discussionsupporting

confidence: 83%

Span of apprehension in schizophrenic patients as a function of distractor masking and laterality.

Elkins¹,

Cromwell²,

Asarnow³

1992

Journal of Abnormal Psychology

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“…For native readers of left-to-right written languages, like English, the right meridian is known to outperform the left in word recognition (Mishkin & Gorgays, 1952), and (Hagenbeek & Van Strien, 2002) reported an upper-right quadrant advantage for letter naming. Worrall and Coles (1976) examined letter recognition across the visual field and found a significant right hemifield advantage only along the right horizontal midline (Worrall & Coles, 1976).…”

Section: Right Advantage In Crowdingmentioning

confidence: 99%

The Bouma law accounts for crowding in fifty observers

Kurzawski

Burchell

Thapa

et al. 2021

Preprint

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Crowding is the failure to recognize an object due to surrounding clutter. Its strength varies across the visual field and individuals. To characterize the statistics of crowding—ultimately to relate psychophysics of crowding to physiology—we measured radial crowding distance and acuity of 105 observers along the four cardinal meridians of the visual field. Fitting the well-known Bouma law — crowding distance depends linearly on radial eccentricity — explains 52% of the variance in log crowding distance, cross-validated. Our enhanced Bourma model, with factors for observer, meridian, and target kind, explains 72% of the variance, again cross-validated. The meridional factors confirm previously reported asymmetries. We find a 0.62 horizontal:vertical advantage, a 0.92 lower:upper advantage, and a 0.82 right:left advantage. Crowding distance and acuity have a correlation of 0.41 at the fovea, which drops to 0.23 at ±5 deg along the horizontal midline. Acuity and crowding represent the size and spacing limits of perception. Since they are dissociated in clinical populations (Song et al., 2014; Strappini et al., 2017) and shown here to be only moderately correlated in our sample of mostly university students, clinical testing to predict real-world performance should consider measuring both. In sum, enhancing the Bouma law with terms for meridian, observer, and target kind provides an excellent fit to our 105-person survey of crowding.

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“…The present group level data, and an extended dataset (n=54), showed a small bias towards more V1 surface area dedicated to the right than left horizontal meridian. It might be that a left-right horizontal meridian asymmetry relates to visual tasks in which an advantage along the right horizontal meridian exists, such as crowding [47][48][49] and letter recognition 50,51 . A larger left than right hemisphere V1 has been previously reported 4 (but see 2,28 ).…”

Section: Group-level Reproduction Of Polar Angle Asymmetriesmentioning

confidence: 99%

Linking individual differences in human primary visual cortex to contrast sensitivity around the visual field

Himmelberg

Winawer

Carrasco

2021

Preprint

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The size and organization of primary visual cortex (V1) varies across individuals. Across individuals, V1 size varies more than twofold. Within individuals, cortical magnification varies with eccentricity and polar angle. Contrast sensitivity has been hypothesized to be limited by cortical resources, and specifically by the number of activated V1 neurons. Here, we quantify the relation between contrast sensitivity and V1 cortical magnification as a function of both individual observers and polar angle. We measured contrast sensitivity at four polar angle meridians in 29 observers. We then used fMRI to measure the size of V1 in the same observers, and the amount of surface area representing the same four meridians as the contrast sensitivity measurements (wedge-ROIs within 15 deg of the meridians, extending from 1 to 8 deg eccentricity). We found that: First, average contrast sensitivity per observer (averaged across polar angles) was predicted by the overall size of V1. Second, contrast sensitivity at each polar angle location was correlated with the surface area of the wedge-ROIs centered at the corresponding meridian. Third, the increases for contrast sensitivity and cortical magnification at the horizontal compared to vertical meridian (horizontal-vertical anisotropy, 'HVA') were strongly correlated: a larger HVA in contrast sensitivity corresponded to a larger HVA in cortical magnification. These results reveal that contrast sensitivity and cortical magnification co-vary across observers and demonstrate a link between perceptual polar angle asymmetries and cortical anatomy. Broadly, the results show a link between visual perception and the idiosyncratic cortical organization of V1 of neurotypical observers.

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Visual field differences in recognizing letters

Cited by 20 publications

References 26 publications

Span of apprehension in schizophrenic patients as a function of distractor masking and laterality.

Span of apprehension in schizophrenic patients as a function of distractor masking and laterality.

The Bouma law accounts for crowding in fifty observers

Linking individual differences in human primary visual cortex to contrast sensitivity around the visual field

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