The origins of individual differences in memory among the elderly: A behavior genetic analysis.

Abstract

The purpose of this investigation was to apply behavior genetic methods to investigate individual differences in memory performance. Memory and various cognitive and lifestyle variables were obtained from 93 monozygotic twin pairs and 67 dizygotic twin pairs aged 60-88 years as part of the Minnesota Twin Study of Adult Development and Aging. Univariate analysis, used to determine the relative influence of genetic and environmental factors on 4 measures of memory (word recall, immediate and delayed text recall, and figure memory), suggested that 55% of the variance in memory performance could be attributed to genetic factors. Bivariate analysis was used to determine the specific variables that mediate the genetic and environmental influences on memory. Results suggested that the relationship between memory and cognitive variables was genetic in nature, whereas the nature of the relationship between memory and lifestyle variables was environmental.

Heritability of cognitive abilities in adult twins: Comparison of Minnesota and Swedish data

“…The present sample consisted of same-sex twins from the Minnesota Twin Study of Adult Development and Aging (MTSADA;Finkel and McGue, 1993;McGue et al, 1993a) and from the Swedish Adoption/Twin Study of Aging (SATSA; Pedersen et aL, 1984Pedersen et aL, , 1991. Sample ascertainment and characteristics of both studies have been described previously (Finkel and McGue, 1993;Lykken et al, 1990;Pedersen et aL, 1984Pedersen et aL, , 1991.…”

“…Sample ascertainment and characteristics of both studies have been described previously (Finkel and McGue, 1993;Lykken et al, 1990;Pedersen et aL, 1984Pedersen et aL, , 1991. In brief, both the Minnesota and the Swedish samples were ascertained from birth records.…”

Longitudinal Memory Performance During Normal Aging: Twin Association Models of APOE and Other Alzheimer Candidate Genes

“…Cross-sectional studies of aging twins from the US, Holland, Sweden, and Denmark find estimates of heritability for memory traits are moderate to high ranging from 32 to 70% (Finkel and McGue, 1993;McClearn et al, 1997;Pedersen et al, 1992;Posthuma et al, 2001) with greater heritability for working or short-term memory than for long-term memory (Johansson et al, 1999;Posthuma et al, 2001 but see Pedersen et al, 1992). Longitudinal analyses of twins from the Swedish Adoption/Twin Study of Aging (SATSA) suggest increases with age in both genetic and environmental variance for some memory traits, such as working memory or delayed figural recognition (Finkel and McGue, 1998;Reynolds et al, 2005).…”

The Minnesota Twin Registry: Current Status and Future Directions

“…Among other projects, Finkel and McGue (1994) estimated that 55% of the variance in memory performance was genetic. They found that the relationship between memory and cognitive variables was primarily genetic in nature, while the relationship between memory and lifestyle variables was environmental in nature.…”