Abstract
The Louisville Twin Study is one of the most intensive twin studies of cognitive ability. The repeated measurements of the twins are ideal for testing developmental twin models that allow for the accumulation of gene–environment correlation via a (P⇒E) transmission process to explain twins’ divergence in mean ability level over time. Using full-scale IQ scores from 566 pairs of twins (MZ = 278; DZ = 288), we tested whether a P⇒E transmission model provided better representation of actual developmental processes than a genetic simplex model. We also addressed whether the induced gene–environment correlation alters the meaning of the latent nonshared environmental factors with a simple numerical method for interpreting nonshared environmental factors in the context of P⇒E transmission. The results suggest that a P⇒E model provided better fit to twins’ FSIQ data than a genetic simplex model and the meaning of the nonshared environment was preserved in the context of P⇒E.
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Acknowledgments
This work was supported by the National Institute on Aging (F31AG044047-01A1, T32AG020500, T32AG000037-37, & R03AG048850-01).
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C. R. Beam, E. Turkheimer, W. T. Dickens, and D. W. Davis declare that they have no conflict of interest.
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This report does not contain any studies with animals performed by any of the authors. Informed consent was obtained from all individual participants included in the study.
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Beam, C.R., Turkheimer, E., Dickens, W.T. et al. Twin Differentiation of Cognitive Ability Through Phenotype to Environment Transmission: The Louisville Twin Study. Behav Genet 45, 622–634 (2015). https://doi.org/10.1007/s10519-015-9756-0
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DOI: https://doi.org/10.1007/s10519-015-9756-0