Tianye Ma¹ (), Weiwei Zhang¹; ¹University of California, Riverside

Visual short-term memory (VSTM) within the internal focus of attention (FoA) can be better recalled. The FoA of VSTM can be manipulated by cuing specific memory items after the offset of the memory stimuli, i.e., the retro-cue. However, the mechanisms for the often-observed retro-cue benefits are under heated debate. The current study aims to investigate whether the mitigation of the categorical bias of VSTM (e.g., shifts towards/away from the prototypical colors) can be a potential mechanism for the retro-cue benefit. Specifically, we tested if the memory item within the FoA shows a weaker categorical bias. In this study, the prototypical colors are defined by an independent color-naming task. We then measured the weight of categorical versus continuous encoding by fitting a mixture model to the responses from a delayed estimation task with colors. The to-be-recalled color has a 70% chance to be retrospectively cued after the offset of the memory items. Participants showed a smaller weight of categorical memory for the cued colors than the other colors. To investigate the temporal dynamics of categorical memory retrieval, we modeled continuous mouse cursor trajectories using a method previously developed by Ma and Zhang (2024, Journal of Vision). Our analysis revealed that the model-estimated weight for categorical memory remained consistently low throughout the retrieval process. This finding contrasts sharply with the phasic ramping observed in categorical retrieval in prior studies that did not employ retro-cue manipulation. These results suggest that visual short-term memory (VSTM) within the focus of attention (FoA) can be effectively insulated from biases introduced by prototypical feature categories.