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Low Cognitive Functioning in Nondemented 80+-Year-Old Twins Is Not Heritable.
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Petrill, Stephen A.; Johansson, Boo; Pedersen, Nancy L.; Berg, Stig; Plomin, Robert; Ahern, Frank; McClearn, Gerald E. – Intelligence, 2001
Studied the genetic influence of low cognitive functioning in 200 pairs of twins aged at least 80 years and identified as not demented. Results suggest that the heritability of low cognitive functioning in this group was nonsignificant, but above-average cognitive functioning shows substantial group heritability. (SLD)
Descriptors: Cognitive Ability, Genetics, Heredity, Low Achievement
Surprising Lack of Sex Differences in Normal Cognitive Aging in Twins
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Finkel, Deborah; Reynolds, Chandra A.; Berg, Stig; Pedersen, Nancy L. – International Journal of Aging and Human Development, 2006
Sex differences in the etiology of normal cognitive functioning in aging remain largely unexplored. We conducted an investigation of genetic and environmental contributions to sex differences in level of cognitive performance and rate of decline in the Swedish Adoption/Twin Study of Aging (SATSA) (Finkel & Pedersen, 2004) data set. Behavioral…
Descriptors: Etiology, Genetics, Cognitive Ability, Gender Differences
Is There G beyond "g"? (Is There Genetic Influence on Specific Cognitive Abilities Independent of Genetic Influence on General Cognitive Ability).
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Pedersen, Nancy L.; And Others – Intelligence, 1994
Genetic effects on specific cognitive abilities as distinct from those on general cognitive ability were studied in 302 pairs of twins (some reared together, some apart) from the Swedish Adoption/Twin Study of Aging. Overall, results showed significant genetic influence on specific abilities independent of influence on general ability. (SLD)
Descriptors: Adopted Children, Aging (Individuals), Biological Influences, Cognitive Ability
Longitudinal and Cross-Sectional Twin Data on Cognitive Abilities in Adulthood: The Swedish Adoption/Twin Study of Aging.
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Finkel, Deborah; Pedersen, Nancy L.; Plomin, Robert; McClearn, Gerald E. – Developmental Psychology, 1998
Collected data on twins' performance on 13 cognitive variables measured three times at three-year intervals. Twins were monozygotic or dizygotic pairs reared together or apart and were in six cohorts ranging in age from 41 through 84 years. Found stable mean cognitive performance across time on eight measures for the younger cohorts, and…
Descriptors: Age Differences, Aging (Individuals), Cognitive Ability, Foreign Countries