Background: The number line task assesses the ability to estimate numerical magnitudes. People vary greatly in this ability, and this variability has been previously associated with mathematical skills. However, the sources of individual differences in number line estimation and its association with mathematics are not fully understood. Aims: This large-scale genetically sensitive study uses a twin design to estimate the magnitude of the effects of genes and environments on: (1) individual variation in number line estimation and (2) the covariation of number line estimation with mathematics. Samples: We used over 3,000 8- to 16-year-old twins from the United States, Canada, the United Kingdom, and Russia, and a sample of 1,456 8- to 18-year-old singleton Russian students. Methods: Twins were assessed on: (1) estimation of numerical magnitudes using a number line task and (2) two mathematics components: fluency and problem-solving. Results: Results suggest that environments largely drive individual differences in number line estimation. Both genes and environments contribute to different extents to the number line estimation and mathematics correlation, depending on the sample and mathematics component. Conclusions: Taken together, the results suggest that in more heterogeneous school settings, environments may be more important in driving variation in number line estimation and its association with mathematics, whereas in more homogeneous school settings, genetic effects drive the covariation between number line estimation and mathematics. These results are discussed in the light of development and educational settings.
Bibliographical noteFunding Information:
This research was supported by Grant from the Russian Science Foundation (project # 14-48-00043) to Tomsk State University; by the Russian Science Foundation (project 15-18-30055); by a Programme Grant (G0901245; previously G0500079) from the U.K. Medical Research Council (MRC); by Eunice Kennedy Shriver National Institute of Child Health and Development (HD059215; HD038075), and (HD075460); by the Qu?bec Ministry of Health, Fonds Qu?b?cois de la Recherche sur la Soci?t? et la Culture; the Fonds de la Recherche en Sant? du Qu?bec; the Social Science and Humanities Research Council of Canada; the National Health Research Development Program; the Canadian Institutes for Health Research; and Sainte-Justine Hospital's Research Center. Michel Boivin is supported by the Canada Research Chair (Tier 1) programme.
- individual differences
- mathematics ability
- number line
- twin studies
PubMed: MeSH publication types
- Journal Article