Differential impact of exogenous and endogenous attention on the contrast sensitivity function across eccentricity

Abstract

Both exogenous and endogenous covert spatial attention enhance contrast sensitivity, a fundamental measure of visual function that depends substantially on the spatial frequency and eccentricity of a stimulus. Whether and how each type of attention systematically improves contrast sensitivity across spatial frequency and eccentricity are fundamental to our understanding of visual perception. Previous studies have assessed the effects of spatial attention at individual spatial frequencies and, separately, at different eccentricities, but this is the first study to do so parametrically with the same task and observers. Using an orientation discrimination task, we investigated the effect of attention on contrast sensitivity over a wide range of spatial frequencies and eccentricities. Targets were presented alone or among distractors to assess signal enhancement and distractor suppression mechanisms of spatial attention. At each eccentricity, we found that exogenous attention preferentially enhanced spatial frequencies higher than the peak frequency in the baseline condition. In contrast, endogenous attention similarly enhanced a broad range of lower and higher spatial frequencies. The presence or absence of distractors did not alter the pattern of enhancement by each type of attention. Our findings reveal how the two types of covert spatial attention differentially shape how we perceive basic visual dimensions across the visual field.

Stimulus-dependent contrast sensitivity asymmetries around the visual field

“…Increasing the SF or eccentricity of the stimulus significantly reduced contrast sensitivity, and this was common across all four meridians. It is well-documented that SF and eccentricity are nonseparable determinants of contrast sensitivity ( Campbell & Robson, 1968 ; De Valois et al, 1982 ; Hilz & Cavonius, 1974 ; Jigo & Carrasco, 2020 ; Kelly, 1977 ; Pointer & Hess, 1989 ; Robson, 1966 ; Rovamo et al, 1992 ; Virsu & Rovamo, 1979 ), thus independently manipulating these parameters allows one to attribute changes in contrast sensitivity to a single parameter. In the baseline condition (4 cpd SF), contrast sensitivity values fell around approximately 50 on the HM and approximately 33 on the VM (corresponding to thresholds at approximately 2% and approximately 3%, respectively).…”

“…As stimulus SF, eccentricity, and size are nonseparable determinants of contrast sensitivity, it is important to independently manipulate these parameters in order to attribute changes in contrast sensitivity to a single parameter ( Pelli & Bex, 2013 ). Contrast sensitivity is dependent upon the stimulus SF ( Baldwin et al, 2012 ; Campbell & Robson, 1968 ; De Valois, Albrecht, & Thorell, 1982 ; Kelly, 1977 ; Robson, 1966 ; Rovamo, Franssila, & Näsänen, 1992 ) and eccentricity ( Baldwin et al, 2012 ; Hilz & Cavonius, 1974 ; Jigo & Carrasco, 2020 ; Pointer & Hess, 1989 ; Rovamo & Virsu, 1979 ). Spatial contrast sensitivity is bandpass around the fovea, peaking at approximately 4 cycles per degree (cpd; Campbell & Robson, 1968 ; Kelly, 1977 ).…”

Stimulus-dependent contrast sensitivity asymmetries around the visual field

“…Increasing the SF or eccentricity of the stimulus significantly reduced contrast sensitivity, and this was common across all four meridians. It is well documented that contrast sensitivity is dependent upon stimulus SF and eccentricity (Campbell & Robson, 1968;De Valois et al, 1982;Hilz & Cavonius, 1974;Jigo & Carrasco, 2020;Kelly, 1977;Pointer & Hess, 1989;Robson, 1966;Rovamo et al, 1992;). In the baseline condition (4 cpd),…”

“…As stimulus SF, eccentricity, and size are non-separable determinants of contrast sensitivity, it is important to independently manipulate these parameters in order to attribute changes in contrast sensitivity to a single parameter (Pelli & Bex, 2013). Contrast sensitivity is dependent upon the stimulus SF (Baldwin et al, 2012;Campbell & Robson, 1968;De Valois, Albrecht, & Thorell, 1982;Kelly, 1977;Robson, 1966;Rovamo, Franssila, & Näsänen, 1992) and eccentricity (Baldwin et al, 2012;Hilz & Cavonius, 1974;Jigo & Carrasco, 2020;Pointer & Hess, 1989;. Spatial contrast sensitivity is bandpass around the fovea, peaking at ~4 cycles per degree (cpd) (Campbell & Robson, 1968;Kelly, 1977).…”

On the joint effect of endogenous spatial attention and defocus blur on acuity: attentional limit to the resolving power of the eye

“…2-4, 6-7). This complements a large number of studies in the literature that have till now discounted the interaction between attention and optics, focusing only on the separate effects of attention [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32] and ocular optics [34][35][36][37][38][39][40] per se in acuity resolution.…”