Suyeon Kim¹, Oakyoon Cha¹; ¹Department of Psychology, Sogang University

Salient visual objects tend to capture attention, even when they are irrelevant. For example, a red apple on a desk can draw attention away from a document you are searching for, unless you are prepared to ignore it. In Experiment 1 of Betteto et al. (2025), participants responded more slowly when a color singleton unexpectedly appeared in the search array (singleton-standard) compared to when no singleton was present (singleton-absent). In contrast, responses were comparable to the singleton-absent condition when the singleton repeatedly appeared at a predictable location (singleton-repeated). Predictable singleton distractors may allow top-down suppression, resulting in reaction times comparable to those without a distractor. However, similar reaction times do not reveal whether additional suppression processes are engaged when the distractor is predictable. To address this, the present study examines whether the strength of suppression differs depending on the presence and predictability of a singleton distractor. To estimate the strength of distractor suppression, we examined rhythmic fluctuations in response times at the alpha frequency (8–12 Hz), which is associated with attentional control. We reanalyzed behavioral data from Experiment 1 of Betteto et al. (2025) using PATS (parametric analysis of temporal structure; Cha & Blake, 2024), a method that detects rhythmic temporal patterns from relatively small datasets. PATS showed that the singleton-repeated condition produced larger alpha-frequency fluctuations within the response time distribution than the singleton-standard and singleton-absent conditions. This pattern was not observed in our reanalysis of Experiment 2, where the distractor did not consistently appear at a fixed location. Overall, these findings suggest that predictable distractor locations trigger stronger inhibitory control, and that the magnitude of behavioral alpha rhythms reflects phase-resetting associated with this suppression.

Acknowledgements: This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (Ministry of Science and ICT) (No. RS-2023-00211668).