Color first, space next, orientation last: A temporal comparison of retro-cue effects in visual working memory.

Retro-cues can enhance performance in visual working memory (VWM) tasks by directing internal attention to relevant items. While spatial retro-cues have been extensively studied, less is known about how different types of feature retro-cues (e.g., color, orientation) compare in effectiveness and temporal dynamics. Across four experiments, we directly contrasted spatial, color, and orientation retro-cues in dual-feature memory tasks and systematically varied cue-probe delays (50-650 ms) to track the time course of retro-cue benefits (RCBs). Results revealed a processing speed hierarchy: color retro-cues elicited larger benefit than spatial retro-cue at the shortest delays (50 ms), followed by spatial retro-cues (200 ms), whereas orientation retro-cues required longer delays (500 ms or more). Notably, color retro-cues produced stronger or more rapid RCBs than spatial cues, suggesting they engage attentional mechanisms more efficiently. In contrast, orientation retro-cues were ineffective unless participants were explicitly required to encode both features. These findings indicate that different retro-cue types differ not only in efficacy but also in how quickly they can modulate memory performance, reflecting feature-specific constraints in attentional selection and cue encoding. Our results challenge the assumption that all feature cues operate uniformly and highlight the importance of considering cue type, task goals, and retrieval context in models of selective attention within working memory.