title: Genetic and Environmental Influences of General Cognitive Ability: Isga valid latent construct?
abstract: Despite an extensive literature, the "g" construct remains a point of debate. Different models explaining the observed relationships among cognitive tests make distinct assumptions about the role ofgin relation to those tests and specific cognitive domains. Surprisingly, these different models and their corresponding assumptions are rarely tested against one another. In addition to the comparison of distinct models, a multivariate application of the twin design offers a unique opportunity to test whether there is support forgas a latent construct with its own genetic and environmental influences, or whether the relationships among cognitive tests are instead driven by independent genetic and environmental factors. Here we tested multiple distinct models of the relationships among cognitive tests utilizing data from the Vietnam Era Twin Study of Aging (VETSA), a study of middle-aged male twins. Results indicated that a hierarchical (higher-order) model with a latentgphenotype, as well as specific cognitive domains, was best supported by the data. The latentgfactor was highly heritable (86%), and accounted for most, but not all, of the genetic effects in specific cognitive domains and elementary cognitive tests. By directly testing multiple competing models of the relationships among cognitive tests in a genetically-informative design, we are able to provide stronger support than in prior studies forgbeing a valid latent construct.
authors.affiliation: Department of Psychiatry, University of California, San Diego, La Jolla, CA ; Center for Behavioral Genomics Twin Research Laboratory, University of California, San Diego, La Jolla, CA.
authors.forename: Matthew S
authors.initials: MS
authors.lastname: Panizzon
authors.affiliation: Department of Psychiatry, University of California, San Diego, La Jolla, CA ; Center for Behavioral Genomics Twin Research Laboratory, University of California, San Diego, La Jolla, CA ; Department of Public Health, University of Helsinki, Finland.
authors.forename: Eero
authors.initials: E
authors.lastname: Vuoksimaa
authors.affiliation: Computational Science Research Center, San Diego State University, San Diego, CA.
authors.forename: Kelly M
authors.initials: KM
authors.lastname: Spoon
authors.affiliation: Department of Psychiatry, University of Chicago, Chicago, IL.
authors.forename: Kristen C
authors.initials: KC
authors.lastname: Jacobson
authors.affiliation: Department of Psychology, Boston University, Boston, MA.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Lyons
authors.affiliation: Department of Psychiatry, University of California, San Diego, La Jolla, CA ; Center for Behavioral Genomics Twin Research Laboratory, University of California, San Diego, La Jolla, CA.
authors.forename: Carol E
authors.initials: CE
authors.lastname: Franz
authors.affiliation: Research Service, St. Louis Veterans Affairs Medical Center, St. Louis, MO ; Department of Biostatistics, St. Louis University School of Public Health, St. Louis, MO.
authors.forename: Hong
authors.initials: H
authors.lastname: Xian
authors.affiliation: Department of Psychiatry, University of Chicago, Chicago, IL.
authors.forename: Terrie
authors.initials: T
authors.lastname: Vasilopoulos
authors.affiliation: Department of Psychiatry, University of California, San Diego, La Jolla, CA ; Center for Behavioral Genomics Twin Research Laboratory, University of California, San Diego, La Jolla, CA ; Center of Excellence for Stress and Mental Health, VA San Diego Healthcare System, La Jolla, CA.
authors.forename: William S
authors.initials: WS
authors.lastname: Kremen