Computational cognitive mechanisms of visual working memory in major depressive disorder and sex differences

This study examined the computational cognitive mechanisms of visual working memory (VWM) in MDD, focusing on memory precision while exploring potential sex differences. 159 Major Depressive Disorder (MDD) patients and 67 healthy controls (HC) completed the color delay estimation task to measure their VWM. The mainstream models of VWM were compared, and the variable-precision (VP) model was the best fit for our data. The Bayesian ANCOVA was used to compare the differences between groups (MDD & HC) and sexes (male & female). Results revealed that MDD had worse memory precision than HC (BF₁₀ = 103.872, decisive evidence for H₁). Specifically, they had larger resource allocation variability (BF₁₀ = 19.421, strong evidence for H₁), indicating that they distributed memory resources more unevenly across different items than HC. In addition, females had better memory precision than males (BF₁₀ = 10.548, strong evidence for H₁). More specifically, they had more initial resources during the color delay estimation task (BF₁₀ = 6.003, substantial evidence for H₁) than males. These findings highlight the critical role of diminished precision, specifically, larger resource allocation variability, in impaired VWM in MDD. Meanwhile, these findings highlight sex differences in memory precision and initial resources of VWM.