§ Abstract
Resource theories of visual cognition propose that visual working memory and mental rotation rely on shared representational constraints, with individual differences in imagery vividness potentially moderating these relationships. However, systematic investigation of performance patterns across these domains remains limited. We tested whether visual working memory precision and mental rotation performance exhibit correlated decline patterns under increasing cognitive demand, and whether imagery vividness moderates these relationships. In a large-scale online study, 181 participants completed visual working memory tasks (varying set size and delay duration), mental rotation tasks (across rotation angles), and imagery vividness questionnaires. We calculated individual slope parameters quantifying how performance declined with increasing cognitive demand in each task. Contrary to resource theory predictions,visual working memory and mental rotation performance patterns showed no significant correlations, with negligible effect sizes. Imagery vividness did not moderate performance in either task across any experimental manipulation. Split-half reliability analyses revealed that three of four slope parameters showed poor internal consistency, providing a methodological explanation for the null correlational findings. These results fail to support theories proposing shared representational constraints between visual working memory and mental rotation processes. The findings highlight critical measurement challenges in individual differences research and suggest that these cognitive domains may operate through more independent mechanisms than previously theorized. Future research should prioritize developing reliable individual difference measures before drawing conclusions about relationships between visual cognitive processe