and found modest heritabilities and a contribution of shared environmental factors to the main EEG frequency bands; however, heritability tended to increase by the end of the first year of life (Orekhova et al., 2003). In summary, developmental twin studies suggest that the strength of genetic influences increases rapidly during development, and heritability reaches adult values already in young children. However, lower heritability in infants can be explained by larger measurement error due to movement and the difficulty of obtaining clean recordings. This alternative explanation can be tested by comparing heritability with test-retest heritability at different ages.
