The Effect of Aging and Attention on Visual Crowding and Surround Suppression of Perceived Contrast Threshold

Abstract

Citation: Malavita MS, Vidyasagar TR, McKendrick AM. The effect of aging and attention on visual crowding and surround suppression of perceived contrast threshold. Invest Ophthalmol Vis Sci. 2017;58:860-867. DOI: 10.1167/iovs.16-20632 PURPOSE. The purpose of this study was to study how, in midperipheral vision, aging affects visual processes that interfere with target detection (crowding and surround suppression) and to determine whether the performance on such tasks are related to visuospatial attention as measured by visual search. METHODS.We investigated the effect of aging on crowding and suppression in detection of a target in peripheral vision, using different types of flanking stimuli. Both thresholds were also obtained while varying the position of the flanker (placed inside or outside of target, relative to fixation). Crowding thresholds were also estimated with spatial uncertainty (jitter). Additionally, we included a visual search task comprising Gabor stimuli to investigate whether performance is related to top-down attention. Twenty young adults (age, 18-32 years; mean age, 26.1 years; 10 males) and 19 older adults (age, 60-74 years; mean age, 70.3 years; 10 males) participated in the study. RESULTS.Older adults showed more surround suppression than the young (F[1,37] ¼ 4.21; P < 0.05), but crowding was unaffected by age. In the younger group, the position of the flanker influenced the strength of crowding, but not the strength of suppression (F[1,39] ¼ 4.11; P < 0.05). Crowding was not affected by spatial jitter of the stimuli. Neither crowding nor surround suppression was predicted by attentional efficiency measured in the visual search task. There was also no significant correlation between crowding and surround suppression.CONCLUSIONS. We show that aging does not affect visual crowding but does increase surround suppression of contrast, suggesting that crowding and surround suppression may be distinct visual phenomena. Furthermore, strengths of crowding and surround suppression did not correlate with each other nor could they be predicted by efficiency of visual search.

Spatial vision in older adults: perceptual changes and neural bases

“…In the same study, they did however find changes to the strength of surround suppression of contrast, and also that older adults required longer search times to correctly perform a visual search task in cluttered visual environment. The results provide further evidence that surround suppression and crowding are distinct mechanistically, and that slower visual search in older adults does not arise from alterations in visual crowding …”

“…measured letter recognition thresholds in the presence of flanking letters in order to measure crowded visual acuity, and found similar levels of crowding across a sample of 54 healthy adults aged between 18 and 76 years. Similarly, Malavita et al . found no difference in para‐foveal crowding strength between older and younger adults.…”

Impacts of older age on the temporal properties of collinear facilitation

“…Besides collinear facilitation, other aspects of visual perception, such as center-surround contrast perception and contour integration, have also been proposed to be dependent on lateral feed-forward and extrastriate feedback interactions (Polat, 1999). The reduced magnitude of facilitation in the presence of synchronous flankers is in line with reports of elevated perceptual surround suppression for suprathreshold center-surround stimuli (Karas & McKendrick, 2009Malavita, Vidyasagar, & McKendrick, 2017). Increased suppressive effects could also play a role in the age-related decline in contour integration (Del Viva & Agostini, 2007;Roudaia, Bennett, & Sekuler, 2008) as mediated by reduced facilitatory benefits from optimally aligned contour elements.…”

Eccentricity dependence of orientation anisotropy of surround suppression of contrast-detection threshold

“…Another visual function that shows a radial/tangential anisotropy is visual crowding, which refers to the decreased recognition of a target due to the presence of surrounding flankers (Pelli, Palomares, & Majaj, 2004). Although visual crowding and surround suppression are thought to be distinct phenomena (Malavita, Vidyasagar, & McKendrick, 2017;Petrov, Popple, & McKee, 2007), they share some similarities. Of relevance here are observations from studies that show that the crowding zone is elongated along the radial axis rather than tangentially, since if flankers are placed along the radial axis, crowding increases more than if it is placed along the tangential axis at a given eccentricity, as shown in psychophysical (Greenwood, Szinte, Sayim, & Cavanagh, 2017;Nandy & Tjan, 2012;Toet & Levi, 1992) and fMRI (Kwon, Bao, Millin, & Tjan, 2014) studies.…”