A meta-analysis of studies of cognitive aging shows that declines in different domains of thinking are interrelated

Tucker-Drob, E. M., Brandmaier, A. M., & Lindenberger, U. (2019). Coupled cognitive changes in adulthood: A meta-analysis. Psychological Bulletin, 145(3), 273–301. doi.org/10.1037/bul0000179

A longstanding question in cognitive aging has been “Does it all go together when it goes?” This meta-analysis indicates that aging-related cognitive declines are interrelated across different domains of thinking. For instance, adults who decline more steeply in their memory performance than other adults as they get older are also likely to decline more steeply in reasoning and processing speed than others over the same period of time. These key insights into how changes in different cognitive abilities interrelate suggest that theories and interventions for cognitive aging will benefit from considering mechanisms that cut across several different domains of thinking in addition to mechanisms that are specific to each individual domain.