The field of view for word recognition: crowding and hemifield asymmetries

White, Alex; Tang, Kenny An; Yeatman, Jason D.

doi:10.1167/jov.20.11.911

Cited by 5 publications

(3 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…At any given eccentricity, the Bouma factor varies with polar angle. The Bouma factor is lower along the horizontal than vertical meridian (Greenwood et al, 2017; Petrov & Meleshkevich, 2011; Toet & Levi, 1992), is higher in the upper than lower meridian (Fortenbaugh et al, 2015; Greenwood et al, 2017; He et al, 1996; Toet & Levi, 1992), tends to be lower in the right than left meridian (Grainger et al, 2010; White et al, 2020) and approximately halves with tangential flankers (Greenwood et al, 2017; Kwon et al, 2014). In this work, we replicated all these asymmetries ( Figure 14 ).…”

Section: Discussionmentioning

confidence: 98%

“…Our power calculation (Table 7) indicates that reliably detecting the right-left asymmetry with the Sloan font requires at least 13 participants. (White et al, 2020) recently reported the right advantage from measurements on 22 observers of proportion correct, instead of crowding distance, for letter trigrams. And Greenwood et al (2017), tested 12 observers using tumbling “clocks”, and reported a right advantage in crowding area (proportional to product of radial and tangential crowding distances) (see their Fig 2A) (Greenwood et al, 2017).…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

The Bouma law accounts for crowding in fifty observers

Kurzawski

Burchell

Thapa

et al. 2021

Preprint

View full text Add to dashboard Cite

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.

show abstract

Section: Discussionmentioning

confidence: 98%

Section: Discussionmentioning

confidence: 99%

The Bouma law accounts for crowding in fifty observers

Kurzawski

Burchell

Thapa

et al. 2021

Preprint

View full text Add to dashboard Cite

show abstract

“…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

View full text Add to dashboard Cite

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.

show abstract

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

2022

View full text Add to dashboard Cite

A central question in neuroscience is how the organization of cortical maps relates to perception, for which human primary visual cortex (V1) is an ideal model system. V1 nonuniformly samples the retinal image, with greater cortical magnification (surface area per degree of visual field) at the fovea than periphery and at the horizontal than vertical meridian. Moreover, the size and cortical magnification of V1 varies greatly across individuals. Here, we used fMRI and psychophysics in the same observers to quantify individual differences in V1 cortical magnification and contrast sensitivity at the four polar angle meridians. Across observers, the overall size of V1 and localized cortical magnification positively correlated with contrast sensitivity. Moreover, greater cortical magnification and higher contrast sensitivity at the horizontal than the vertical meridian were strongly correlated. These data reveal a link between cortical anatomy and visual perception at the level of individual observer and stimulus location.

show abstract

The field of view for word recognition: crowding and hemifield asymmetries

Cited by 5 publications

References 0 publications

The Bouma law accounts for crowding in fifty observers

The Bouma law accounts for crowding in fifty observers

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

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

Contact Info

Product

Resources

About