Load-Dependent Retrospective Attentional Benefits During Visual Working Memory

Working memory (WM) temporarily holds and processes information, with its precision decreasing as load increases. Although retro-cues enhance WM precision by focusing attention on relevant items, neural mechanisms driving this effect across varying loads remain unclear. We recorded electroencephalography (EEG) signals during two experiments where participants performed a retrospective-cue WM task under low and high loads. We found that retro-cues significantly enhanced recall precision and sped response times, with larger precision benefits under high load. Alpha (8-12 Hz) activity showed load-dependent attentional modulation during retention, including later delayed desynchronization (ERD) and prolonged lateralization modulation index (MI) under higher load. Under high load, the retro-cues caused slower theta frequency, suggesting phase coding mechanisms in WM. Inverted encoding model (IEM) results revealed more precise mnemonic representation under low load, supporting less noise and more refined encoding. These findings highlight WM adaptive nature, flexibly adjusting to changing cognitive demands through dynamic attentional control.