Aim: The aim of the present study was the qualitative comparison of working memory capacity of young children and older adults through the investigation of the latent structure stability or change in Working Memory capacity (WM) in childhood and aging, using Multiple Group Confirmatory Factor Analysis (MGCFA).
Method: The sample consisted of 62 kindergarten and 56 elementary school students (age range: 4-8 years) and 52 young-old adults and 54 old-old adults (age range: 60-94 years). Adults were asked to complete the Mini-Mental State Examination (MMSE) and the Geriatric Depression Scale-15 (GDS-15) as screening tests. The children were examined via the Raven Colored Progressive Matrix (CMP) test for the same reason. WM was examined via four measures of Working Memory Test Battery for Children (WMTB-C).
Results: MGCFA applied to the data of the kindergarten students' subsample, elementary school students' subsample, young-old and old-old adults' subsamples as well as of older adults with low (0-9 years of education) educational level. Initially, through MGCFA, four "models" were confirmed, one for each age-related subsample, and they were different from each other. However, when the same method was applied exclusively to young-old and old-old adults with low educational level, the models that emerged were similar to the kindergarten students' model.
Conclusion: When we "keep" the educational level equal (low) for all, the hypothesis of retrogenesis is confirmed. Cognitive reserve appears to be protective, keeping differentiated WM's components in every age group other than that of kindergarten students. The results support the "retrogenetic" hypothesis, mainly due to the finding of a delay in WM components' development in the group of kindergarten students, and their dedifferentiation in the low-educated young-old and old-old adults.