Table 2 presents the variance components of Internalizing at five different discrete levels, scaled in standard deviation units (z-scored): −2, −1, 0, 1, and 2 standard deviations away from the mean of the moderator. The unstandardized genetic component of variance decreased from low to high levels of Quality; because the total phenotypic variance in Internalizing also decreased from low to high levels of Quality, the heritability of Internalizing was greatest when Quality was lowest. At the extreme low end of Quality, the proportion of variance in Internalizing due to genetic effects was 29%, while there were essentially no genetic effects on Internalizing at high levels of Quality (h2=5%). Similarly, non-shared environmental effects were strongest at low levels of Quality (e2=68%) and decreased as relationship quality became more positive. In contrast, shared environmental influences were weakest at low levels of Quality (c2=3%) and increased linearly with level of Quality, until, at the highest levels of Quality, a majority of the variance in Internalizing was due to shared environmental influences (c2=61%). Examination of the genetic correlations between Internalizing and Marital Quality showed
