2025/04/13 by Lv, Chenxi
Psychology · #FOS: Psychology #Psychology #Social and Behavioral Sciences
paper · doi:10.17605/osf.io/2yb3u
Visual working memory (VWM) is a core component of the human cognitive system, and understanding the neural mechanisms underlying its capacity limits has been a central focus of cognitive neuroscience. Previous studies have shown that VWM capacity relies on the coordinated regulation of the prefrontal, parietal, and occipitotemporal cortices. However, the specific cognitive processing mechanisms associated with different brain regions during memory storage remain a topic of debate. For instance, some studies suggest that the prefrontal cortex functions as a “resource allocator”, exhibiting sensitivity to object complexity, while others emphasize its critical role in feature binding. Additionally, the posterior parietal cortex has been identified not only as a neural marker of VWM capacity limits but also as a key region involved in the dynamic regulation of resource allocation. Many prior studies have used multidimensional experimental stimuli, which may have introduced confounding effects related to stimulus dimensions or memory representation strategies. Moreover, systematic investigations into the graded effects of object complexity and quantity, as well as their interaction, remain limited. To address these gaps, this study employed unidimensional stimuli and integrated behavioral modeling with functional magnetic resonance imaging (fMRI) to conduct two experiments, systematically examining the effects of object complexity and quantity on VWM capacity and their underlying neural mechanisms. Experiment 1 used performance in a visual search task as an index of object complexity and performance in a change detection task as a measure of VWM capacity. A nonlinear mathematical model was constructed to explore the role of object complexity in VWM capacity. The results revealed a significant interaction between object quantity and complexity, indicating a synergistic effect on VWM capacity. Experiment 2 employed fMRI to further investigate the cognitive and neural mechanisms underlying the effects of object complexity and quantity on VWM capacity by analyzing brain activation patterns under different conditions. The behavioral results were consistent with those of Experiment 1, showing a negative correlation between object complexity and VWM capacity, as well as a significant interaction between object quantity and complexity.