Musicians, Memory, and General Cognitive Ability: A Commentary on Grassi et al. (2025)

Abstract

When cognitive variables show a positive manifold, mainstream psychometric theory suggests that their common variance should be modeled first. Treating correlated cognitive scores as if they were separately interpretable outcomes instead requires explicit theoretical justification. We comment on Grassi et al., an important multilab study on musicians and nonmusicians, and reexamine their cognitive results at the latent level. Using multigroup and multilevel structural equation models on the same data set, we ask whether the reported pattern can be parsimoniously understood as a difference in shared cognitive variance rather than as a set of task-specific advantages. The results suggest that under this latent-variable representation, the musician advantage is mostly captured by a latent common factor, whereas melody span retained a clear residual advantage and vocabulary showed, at most, a smaller task-specific deviation. The focus, therefore, is not just whether musicians differ from nonmusicians on a set of observed tasks, possibly controlled for each other, but also how such differences should be interpreted once those tasks are allowed to share variance. Grassi et al. provided an excellent example of open, collaborative work that the field should actively encourage. We suggest that this kind of enterprise should also be paired with equally strong and theoretically grounded measurement modeling.