Latent Change Models of Adult Cognition: Are Changes in Processing Speed and Working Memory Associated With Changes in Episodic Memory?

Abstract

The authors used 6-year longitudinal data from the Victoria Longitudinal Study (VLS) to investigate individual differences in amount of episodic memory change. Latent change models revealed reliable individual differences in cognitive change. Changes in episodic memory were significantly correlated with changes in other cognitive variables, including speed and working memory. A structural equation model for the latent change scores showed that changes in speed and working memory predicted changes in episodic memory, as expected by processing resource theory. However, these effects were best modeled as being mediated by changes in induction and fact retrieval. Dissociations were detected between cross-sectional ability correlations and longitudinal changes. Shuffling the tasks used to define the Working Memory latent variable altered patterns of change correlations.

A diffusion model analysis of adult age differences in episodic and semantic long-term memory retrieval.

“…Finally, on the basis of correlational analyses, age deficits in episodic memory (including tasks with high context-memory demands) have also been linked to age-related declines in general cognitive processing resources such as speed or working memory. Importantly, however, these variables appear not to account for all of the age-related variance in episodic memory measures (e.g., Hertzog, Dixon, Hultsch, & MacDonald, 2003;Verhaeghen & Salthouse, 1997).…”

Neuropsychological performance in advanced age: Influences of Demographic factors and Apolipoprotein E: Findings from the Cache County Memory Study

“…Aging is associated with selective losses in functions related to psychomotor speed, sensorimotor function, and efficiency of information processing (Hertzog et al, 2003;Salthouse, 1996), some of which may be genetically mediated (Finkel et al, 2000). Other cognitive functions affected by age are memory retrieval, attentional capacity, and executive skills.…”

Aging and self-regulated language processing.

“…Even though age-graded changes in processing capacity are highly prevalent across different domains of cognition (Salthouse, 1996;Salthouse & Ferrer-Caja, 2003), there are also individual differences in rates of cognitive decline (e.g., Hertzog & Schaie, 1986;Lövden et al, 2004;Zimprich & Martin, 2002). Rates of age-related change differ for resources such as working memory that are known to be relevant for textbase construction and text recall (Hertzog, Dixon, Hultsch, & MacDonald, 2003). Moreover, longitudinal changes in working memory reliably predict changes in text recall Hultsch et al, 1998).…”