Yifei Wu¹, Khayla Santiago¹, Chunyue Teng¹; ¹Lawrence University

Attention fluctuates rhythmically over time, influencing both visual perception and visual working memory (WM). Previous research has demonstrated periodicity in attentional sampling across these domains, yet it remains unclear how rhythmic attention coordinates the concurrent processing of external and internal visual representations. The current study investigates whether rhythmic attentional sampling is modulated by competition between these processes. Participants performed a dual-task paradigm to maintain a visual stimulus in WM while performing a concurrent perceptual judgment. In Experiment 1, both tasks involved orientation judgments, maximizing competition between internal and external processing. In Experiment 2, the perceptual task required luminance judgments, while the WM task involved orientation, reducing direct competition. Stimulus onset asynchrony (SOA) between the perceptual stimulus onset and the probe onset varied systematically across 50 intervals (0.5–1.5 seconds, in 0.02s steps). Time-frequency decomposition was applied to response time and accuracy using a Fast Fourier Transform. Spectral power and phase angles were analyzed in the theta and alpha frequency ranges (3–15 Hz). Non-parametric permutation testing assessed significance in increased spectral power across frequencies. In Experiment 1 (High Competition), performance fluctuations in both tasks were observed in the theta and low-alpha range. In Experiment 2 (Low Competition), rhythmic fluctuations in WM performance were identified at ~6 Hz (theta range). Cross-task comparisons showed greater phase offset between WM and perceptual performance in Experiment 1 than in Experiment 2, suggesting increased interference. These findings suggest that visual perception and WM are governed by a shared oscillatory control process. Moreover, the phase offset between internal and external sampling appears to increase under high competition, potentially serving as a mechanism for resolving representational interference. These results support the idea that rhythmic attention dynamically regulates access to perceptual and mnemonic representations based on task demands.