Hidden Shapes and Jigsaw Puzzles.

Many pieces of the puzzle are still missing in our explanation of the etiology of individual differences in spatial ability. Understanding the sources of this variation can have important educational implications. Not only spatial ability is an independent predictor of academic success, it is also associated with mathematical ability. In this study we assessed spatial ability (Hidden Shapes and Jigsaw Puzzles) in the large representative population-based UK Twins Early Development Study when the twins were 12 years old. These aspects of spatial ability are only moderately heritable at this age. We also explored sources of co-variation between spatial ability and mathematical ability in the same sample. Our multivariate twin analysis showed that mathematics and spatial ability largely share the same genetic background. Moreover, our behavioral genomic analysis identified a set of DNA markers (SNPs) associated with both spatial and mathematical ability. Finally, we explored gender differences in spatial abilities, showing small but significant differences between boys and girls in this sample of almost 4000 pairs of twins. However, only girls with twin sisters were significantly worse in spatial ability that boys.