Crowding expands and is less sensitive to target-flanker differences during a shift of visual attention

Nador, Jeff; Reeves, Adam

doi:10.1016/j.visres.2023.108305

Cited by 1 publication

(1 citation statement)

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“…To perceive the whole object, the local features (grouping) of an object must be combined. Nador and Reeves [7] found that peripheral crowding is eliminated when both spatial frequency and the orientation of the Gabor flankers differ from those of the Gabor target, but changing just one of them has almost no effect. If the local and basic features comply with the Gestalt principles [8,9], they can be combined.…”

Section: Introductionmentioning

confidence: 99%

Probing the Bottleneck of Awareness Formed by Foveal Crowding: A Neurophysiological Study

Siman-Tov,

Lev,

Polat

2024

Brain Sciences

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Crowding occurs when an easily identified isolated stimulus is surrounded by stimuli with similar properties, making it very difficult to identify. Crowding is suggested as a mechanism that creates a bottleneck in object recognition and awareness. Recently, we showed that brief presentation times at the fovea resulted in a significant crowding effect on target identification, impaired the target’s color awareness, and resulted in a slower reaction time. However, when tagging the target with a red letter, the crowding effect is abolished. Crowding is widely considered a grouping; hence, it is pre-attentive. An event-related potential (ERP) study that investigated the spatial–temporal properties of crowding suggested the involvement of higher-level visual processing. Here, we investigated whether ERP’s components may be affected by crowding and tagging, and whether the temporal advantage of ERP can be utilized to gain further information about the crowding mechanism. The participants reported target identification using our standard foveal crowing paradigm. It is assumed that crowding occurs due to a suppressive effect; thus, it can be probed by changes in perceptual (N1, ~160 ms) and attentive (P3 ~300–400 ms) components. We found a suppression effect (less negative ERP magnitude) in N1 under foveal crowding, which was recovered under tagging conditions. ERP’s amplitude components (N1 and P3) and the behavioral proportion correct are highly correlated. These findings suggest that crowding is an early grouping mechanism that may be combined with later processing involving the segmentation mechanism.

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Section: Introductionmentioning

confidence: 99%