Analyses have suggested math anxiety is a multidimensional construct. However, previous behavioral genetic work examining math anxiety was unidimensional. Thus, the purpose of the present study was to examine different approaches for specifying behavioral genetic models of math anxiety as a multidimensional construct. Three models were compared: a unidimensional model, a three dimension multidimensional model, and a bi-factor model, which partitioned variance into one common factor shared across three dimensions of math anxiety and examined residual variance in each dimension. The best fitting model was a bi-factor AE model, which suggested moderate heritability of general math anxiety and that each dimension of math anxiety had unique etiological influences not accounted for by shared variance with the general math anxiety factor. Thus, while there was evidence of shared etiology, there was also evidence of some etiological distinction across dimensions of math anxiety. The results demonstrate the importance of taking into account the dimensionality of the scale when interpreting similarity across twins.
