Delayed foveal and parafoveal masks disrupt peripheral target processing

Visual perception arises from the interplay of the fast, feedforward sweep of information processing and a slower, recurrent processing that refines and stabilizes perceptual representations. In this study, we investigated how foveal and parafoveal masks, aimed to disrupt re-entrant visual processing, interact with peripherally presented vernier targets. Participants performed a vernier discrimination task, in which the target was followed by a mask presented at various spatial locations and stimulus onset asynchronies (SOA). In Experiment 1, the mask consisted of a dynamic noise patch, in experiments (2-4), the mask consisted of two vertical lines. We found robust masking effects at SOAs up to 250 ms, indicating that target information remains in a prolonged vulnerable state well beyond the initial feedforward sweep, even in a simple low-level discrimination task. Importantly, the target and mask never overlapped retinotopically. The strongest impairments occurred when parafoveal masks appeared in the direction of the target ∼100 ms after target onset. These findings support models in which target representations require recurrent feedback for stabilization and show that such feedback is spatially selective, extending along the fixation-target axis. We propose that, during peripheral discrimination, the visual system dynamically allocates processing resources to a task-relevant region, making stimuli appearing within this region particularly disruptive. This extended temporal and spatial vulnerability challenges classical accounts that attribute masking solely to early retinotopic interactions and highlights the role of recurrent, spatially targeted feedback in shaping conscious visual perception.