PT  - JOURNAL ARTICLE
AU  - McClearn, Gerald E.
AU  - Johansson, Boo
AU  - Berg, Stig
AU  - Pedersen, Nancy L.
AU  - Ahern, Frank
AU  - Petrill, Stephen A.
AU  - Plomin, Robert
TI  - Substantial Genetic Influence on Cognitive Abilities in Twins 80 or More Years Old
AID  - 10.1126/science.276.5318.1560
DP  - 1997 Jun 06
TA  - Science
PG  - 1560--1563
VI  - 276
IP  - 5318
4099  - http://science.sciencemag.org/content/276/5318/1560.short
4100  - http://science.sciencemag.org/content/276/5318/1560.full
SO  - Science1997 Jun 06; 276
AB  - General and specific cognitive abilities were studied in intact Swedish same-sex twin pairs 80 or more years old for whom neither twin had major cognitive, sensory, or motor impairment. Resemblance for 110 identical twin pairs significantly exceeded resemblance for 130 fraternal same-sex twin pairs for all abilities. Maximum-likelihood model-fitting estimates of heritability were 62 percent for general cognitive ability, 55 percent for verbal ability, 32 percent for spatial ability, 62 percent for speed of processing, and 52 percent for memory. There was also evidence for the significant influence of idiosyncratic experience as the environmental component that most determines individual differences in cognitive abilities late in life.