The Scarr-Rowe Interaction in Complete Seven-Year WISC Data from the Louisville Twin Study: Preliminary Report
- 232 Downloads
We examine updated Wechsler IQ data in 7-year old twins from the Louisville Twin Study for evidence of an interaction between the heritability of IQ and socioeconomic status. Data records that had never been entered were recovered, allowing us to increase previously reported sample sizes by more than 20 %. Twin families were assigned socioeconomic status scores using a Hollingshead index based on parental education and occupation. A structural equation model in which genetic and environmental variances were modeled as squared linear functions of SES provided ambiguous replication of earlier findings from the National Collaborative Perinatal Project: relations between SES and heritability for performance and full scale IQ were in the same direction as the previous report, but at p < 0.07. As was the case in Turkheimer et al. (Psychol Sci 14(6):623–628, 2003), no interaction was found for VIQ. These results cannot yet be taken as a definitive replication of Turkheimer et al. (Psychol Sci 14(6):623–628, 2003). Many more measurement occasions, subtests and environmental moderators remain to be analyzed.
KeywordsGE interaction Wechsler intelligence scale for children Socioeconomic status
This work was supported by grants 1R03AG048850-01, T32AG020500, T32AG000037-37, F31AG044047-01A1 from the National Institute of Aging.
Compliance with Ethical Standards
Conflict of Interest
Eric Turkheimer, Christopher E. Beam and Deborah W. Davis declare that they have no conflict of interest.
Human and Animal Rights and Informed Consent
The secondary data analysis reported here was approved by the Institutional Review Board for the Social and Behavioral Sciences at the University of Virginia. All procedures followed in the secondary data analysis reported here were in accordance with the ethical standards of the responsible committee on human experimentation (institutional and national) and with the Helsinki Declaration of 1975, as revised in 2000 (5). Informed consent was obtained from all patients for being included in the study.
- Muthén LK, Muthén BO (1998–2015) Mplus user’s guide, 6th Ed. Muthén & Muthén, Los AngelesGoogle Scholar
- Tucker-Drob E, Bates T (2014) The world’s literature on gene x social class interactions on cognitive ability: a meta-analysis. In: Presentation at 2014 meeting of the behavior genetics association, CharlottesvilleGoogle Scholar
- Turkheimer E, Horn EE (2014) Interactions between socioeconomic status and components of variation in cognitive ability. In: Behavior genetics of cognition across the lifespan. Springer, New York, pp 41–68Google Scholar
- Turkheimer E, Beam CE, Finkel D, Dickens WT, Sederberg R, Davis DW (2015) The Scarr-Rowe Interaction in the Louisville Twin Study. In: Paper presented at the meeting of the Behavior Genetics Association, San DiegoGoogle Scholar