Shandell Pahlen, Nayla R Hamdi, Anna K Dahl Aslan, Briana N Horwitz, Matthew S Panizzon, Inge Petersen, Catalina Zavala, Kaare Christensen, Deborah Finkel, Carol E Franz, Margaret Gatz, Wendy Johnson, William S Kremen, Robert F Krueger, Jenae M Neiderhiser, Chandra A Reynolds, Nancy L Pedersen, Matt McGue
Age moderation of genetic and environmental contributions to Digits Forward, Digits Backward, Block Design, Symbol Digit, Vocabulary, and Synonyms was investigated in a sample of 14,534 twins aged 26 to 98 years. The Interplay of Genes and Environment across Multiple Studies (IGEMS) consortium contributed the sample, which represents nine studies from three countries (USA, Denmark, and Sweden). Average test performance was lower in successively older age groups for all tests. Significant age moderation of additive genetic, shared environmental, and non-shared environmental variance components was observed, but the pattern varied by test...
May 2018: Intelligence