The Louisville Twin Study (LTS) was established in 1959, and continuously funded for forty years;data collection was terminated in 2003. The LTS includes data on over 1500 twins born in the Louisville area. Data were collected on physical and medical parameters, health, families, school performance and cognitive ability at 16 different measurement occasions between three months and fifteen years of age. Repeated measurements of cognitive ability will be used to answer important questions about the causes of differences in ability through development. Data will be fit to an integrative model that will provide explanations of some of the most important observations regarding intellectual development during childhood: the importance of genetic factors increases throughout childhood, the role of genetics is diminished among children raised in impoverished environments, and the temporal stability of individual twins and siblings relative their family members increases with age. The hypothesis is that all three phenomena occur as a result of a process of ongoing matching of children to environments, through which children with the greatest observed cognitive abilities are exposed to the most enriching environments. In addition, funds are requested to support the ongoing recovery and archiving of the data from the LTS, so they can eventually be made available to the scientific community at large.

Public Health Relevance

The mechanisms underlying the development of differences in cognitive ability are crucially important to multiple domains of public health. The Louisville Twin Study contains unique data on the ability scores of twins at sixteen different measurement occasions between three months and fifteen years of age. The Louisville Twin Study also includes an enormous amount of other medical and psychological data that should be made available to the scientific community.

National Institute of Health (NIH)
National Institute on Aging (NIA)
Small Research Grants (R03)
Project #
Application #
Study Section
Special Emphasis Panel (ZRG1)
Program Officer
King, Jonathan W
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
University of Virginia
Schools of Arts and Sciences
United States
Zip Code
Turkheimer, Eric (2016) Weak Genetic Explanation 20 Years Later: Reply to Plomin et al. (2016). Perspect Psychol Sci 11:24-8
Turkheimer, Eric; Beam, Christopher E; Davis, Deborah W (2015) The Scarr-Rowe Interaction in Complete Seven-Year WISC Data from the Louisville Twin Study: Preliminary Report. Behav Genet 45:635-9
Davis, Deborah Winders; Finkel, Deborah; Turkheimer, Eric et al. (2015) Genetic and Environmental Contributions to Behavioral Stability and Change in Children 6-36 months of Age Using Louisville Twin Study Data. Behav Genet 45:610-21
Finkel, Deborah; Davis, Deborah Winders; Turkheimer, Eric et al. (2015) Applying Biometric Growth Curve Models to Developmental Synchronies in Cognitive Development: The Louisville Twin Study. Behav Genet 45:600-9
Beam, Christopher R; Turkheimer, Eric; Dickens, William T et al. (2015) Twin Differentiation of Cognitive Ability Through Phenotype to Environment Transmission: The Louisville Twin Study. Behav Genet 45:622-34