Memory Loves Company: Related Object Pairs Benefit Visual Working Memory

Visual working memory (VWM) is capacity-limited, yet performance improves when items can be organized into meaningful units. We asked whether functionally related object pairs benefit VWM and whether people’s judgments of relatedness predict participants’ performance on memory tasks. We curated a stimulus set of 160 line drawings arranged into 80 related and 80 unrelated pairs. Participants viewed four pairs of objects and then identified the new object in a probe display. Results showed a robust accuracy advantage for related over unrelated pair displays, with strong split-half reliability. This finding was replicated in a version where the probe display used pairs rather than single objects. To validate our relatedness manipulation, we collected Likert ratings of both semantic relatedness and action compatibility. The two rating methods showed a strong correlation with each other, as well as with the relatedness benefit observed in the memory experiments, providing further support for our manipulation. However, within the related and unrelated sets considered separately, subjective reports of relatedness did not predict variability in memory performance, and this replicated with a follow-up ratings task. Cross-condition correlations in the memory task indicated stable differences for individual objects regardless of relatedness. Together, the results show that functional pairing reliably boosts VWM - consistent with chunking - yet fine-grained variability in memorability is driven by object- and pair-level properties not captured by perceived relatedness.