Poster #74 - Etiology of Mathematical Performance: A Meta-Analysis of Twin Studies

• In Event: 3-106 - Poster Session 11
  In Poster Session: PS 11 Section - Education, Schooling

Integrative Statement

Introduction
Mathematics performance is predictive of important life outcomes (Murnane, et al., 1995). Twin studies, which provide a unique opportunity to investigate estimates of genetic and environment influences (Boomsma, et al., 2002), have been used in an attempt to improve our understanding of how mathematical performance develops (Hart et al., 2009; Lukowski et al., 2017). Here, using meta-analysis, we examined the etiology, or the genetic and environmental influences, of mathematical performance while examining potential moderators. This type of comprehensive review, will help us to understand the range of etiological estimates we see across studies by establishing trends for differences in the etiological influences.

Methods
An initial literature search yielded 4,582 articles. After screening using inclusionary and exclusionary criteria, 28 articles remained. Using the metafor package in R (Viechtbauer, 2015), the genetic and environmental influences of mathematical performance were examined, while considering multiple moderators: year of publication, age of sample, method of zygosity determination, country, twin project, and math skill. Moderators were examined using the Q statistic. Pair-wise comparisons allowed us to examine the relation between moderator subgroups. Sample dependency was controlled for using the metafor package in R.

Results
Results indicated a large heritability estimate (h2=.54), a moderate but significant shared environmental estimate (c2=.25), and a moderate but significant non-shared environmental estimate (e2=.25). Variability in the genetic and environmental estimates was large.
Across all moderators, heritability explained more variance in mathematical performance than shared-environmental influences, except for estimates drawn from the Early Childhood Longitudinal Survey twin sample. When examining pairwise comparisons across age groups, the only difference was that shared environmental estimates drawn from participants in the 6th – 8th were higher than for the participants in the 3rd-5th grade. When examining country as a moderator, pair-wise estimates revealed that the only difference was that the Canada twin projects had higher heritability estimates than the Canadian twin project. For the shared environment, Australia had a higher estimate than did US twin projects. When examining pair-wise comparisons of math skills, heritability estimates were higher for approximate number sense (ANS) than for word problem solving. For the shared environment, the relation with ANS was weaker than all other math skills, except for word problem solving where they did not significantly differ. All pair-wise comparisons between higher level math skills and lower level math skills (i.e. ANS, word problems) revealed lower shared environmental estimates for lower level math skills when compared with higher level skills subgroup.

Discussion
Here, results indicate significant influences of heritability and both shared and non-shared environmental estimates on mathematical performance. In addition, the examination of moderators help to explain some of the variability displayed in estimates across studies, which can help to inform our understanding of math development. Results indicate that country and type of math skill assessed can impact genetic and environmental influences on mathematical performance. Specifically, higher level math skills have a larger shared environmental influence, which may suggest factors such as the home math environment could be important for the development of these skills.

Authors

• Amanda L McGraw, Florida State University
  Presenting Author

• Colleen M Ganley, Florida State University
  Non-Presenting Author

• Sara Hart, Florida State University
  Non-Presenting Author

• Michael P Kaschak, Florida State University
  Non-Presenting Author