The impact of dimension switching on visual short-term memory

Visual short-term memory (vSTM) refers to the subset of the cognitive system responsible for storing visual information over short periods of time. While much research has focussed on its capacity limitations, less is known about how vSTM operates in dynamic environments where priorities shift across feature dimensions. In this study, we bridge research on vSTM and cognitive control by embeddeding change detection (Experiments 1 and 2) and delayed estimation (Experiment 3) paradigms within a task switching paradigm, where the relevant feature dimension (colour or orientation) either repeated or switched across trials. Across all experiments we observed a cost to vSTM performance on switch relative to repetition trials. Mixture modelling of delayed estimation responses revealed that these switch costs were not due to reduced memory precision or memory failures, but rather to a selective increase in non-target responses reflecting feature--location binding errors. We propose that dimension switching selectively impairs the binding of feature values to locations and allows interference from irrelevant (but recently attended) feature dimensions. This suggests a core limitation in the dynamic prioritisation of task-relevant feature dimensions, and demonstrates that vSTM is sensitive to failures of attentional control, not just capacity limits.