Amelia Harrison¹, Thomas Sprague¹; ¹UC Santa Barbara

A large body of work reports that perceptual sensitivity declines when attention is distributed across multiple spatial locations compared to when it is focused on a single location (e.g., Ling & Carrasco, 2006; Popovkina et al., 2021). Neural responses often show similar attenuation of stimulus representations under distributed attention (McMains & Somers, 2005; Toffanin et al., 2009). However, these effects are not universal: performance costs can be minimized by changes in decision demands (Harrison et al., 2023), and recent findings demonstrate that distributed spatial attention does not always reduce neural responses (Harrison et al., VSS 2024; Harrison & Sprague, SfN 2025). These observations suggest that measured ‘capacity limits’ may arise from task-specific factors rather than fixed constraints in attentional modulations of sensory processing. To characterize how task structure shapes behavioral impacts of focused versus distributed attention, we developed a framework in which stimulus input remains constant while attentional and decisional demands vary. On each trial, observers viewed two iso-eccentric stimuli and were cued to attend to one or both peripheral locations. Across task variants, participants either monitored for a target and immediately reported its identity at the pre-cued location(s), or used a post-cue after a brief delay to determine which stimulus should be reported, requiring brief maintenance in visual working memory. These manipulations dissociate sensory selection, target monitoring, working-memory storage, and decision readout while preserving visual stimulation across conditions. Across tasks, aspects of behavioral performance (RT, discriminability) depended on the number of attended locations, though the magnitude of these differences varied substantially with task factors. These results indicate that behavioral limits in spatial attention are influenced by specific features such as cueing scheme and report requirements. By isolating these components within a common stimulus framework, this approach identifies when distributed-attention costs reflect sensory selection, monitoring demands, or post-perceptual decision processes.