Figure 1. Best fitting structural equation model for genetic and environmental determinants of attention score, controlling for gender.

Note: Rectangles represent the observed variance for each age, and circles represent the latent factors. For additive genetic influences (A₁₂, A₁₄ and A₁₆) and shared environmental influences (C₁₂, C₁₄ and C₁₆), simplex model is shown. A Cholesky (triangular decomposition) model is shown for the non-shared environmental effects (E₁₂, E₁₄ and E₁₆).