Genetic and Environmental Influences on Verbal Fluency in Middle Age: A Longitudinal Twin Study. Journal Article uri icon



  • Mounting evidence suggests that measures of phonemic fluency and semantic fluency are differentially associated with other cognitive and health phenotypes, but few studies have examined their shared and unique variance, especially using genetically-informative designs. In this study, 1464 middle-aged twins completed six fluency subtests at up to two time-points (mean age 56 and 62 years). Confirmatory factor analyses supported a two-factor solution: a General Fluency latent factor explained variation in all six subtests and a Semantic-Specific factor accounted for additional variance in semantic subtests. Both factors were explained primarily by genetic influences at both waves (a2 = 0.57-0.76). There was considerable stability of individual differences over 6 years (r = .90 for General Fluency, r = .81 for Semantic-Specific), especially for genetic influences (rg = .94 and 1.0, respectively). These results suggest that semantic fluency can be viewed as a combination of general and semantic-specific variance, but phonemic fluency is captured entirely by the general factor.

publication date

  • September 1, 2018

has restriction

  • green

Date in CU Experts

  • April 13, 2023 8:42 AM

Full Author List

  • Gustavson DE; Panizzon MS; Elman JA; Franz CE; Beck A; Reynolds CA; Jacobson KC; Xian H; Toomey R; Lyons MJ

author count

  • 11

Other Profiles

Electronic International Standard Serial Number (EISSN)

  • 1573-3297

Additional Document Info

start page

  • 361

end page

  • 373


  • 48


  • 5