Working memory (WM) capacity has remained a central topic of individual differences research due to its relationship with various higher order cognitive abilities. While studies investigating individual differences with WM capacity are common, there are comparatively fewer studies investigating individual differences with WM precision. Mixture models have been used to derive distinct capacity and precision parameters from continuous report tasks and thus provide an avenue to explore the potentially unique contributions of WM capacity and precision to the relationship between WM and other well-known correlates. Across three studies, we examined the psychometrics of the modeled precision parameter derived from the standard mixture model, the relationship between precision for different feature types (e.g., color and spatial location), and the relationship between precision and a well-known correlate of WM capacity: fluid intelligence. In all three studies, we consistently found a significant positive correlation between spatial WM precision and fluid intelligence, but this relationship was not consistent or present across other feature types. Additionally, we did not consistently find significant correlations between WM precision estimates among feature types. We found acceptable measurement reliability for color and spatial precision parameters across Studies 1 and 2, acceptable reliability for only spatial precision in Study 3, but not for the precision parameters of other feature types. In sum, we found that precision can be a reliable measure in individual differences research and may contribute separately to or have differing relationships with some higher order cognitive constructs like fluid intelligence, but these patterns of results may be feature-specific. (PsycInfo Database Record (c) 2026 APA, all rights reserved).
Campbell et al. (Mon,) studied this question.