Table 6 presents the age-trends in the genetic and environmental contribution to phenotypic stability. For the linear models, the BIC comparisons indicate that including age as a moderator of the genetic contribution to stability actually reduces model parsimony without a compensatory increase in model fit according. In others words, genetic effects exert a constant, moderate effect (b0 = .358, p < .001) on phenotypic stability across the lifespan. On the other hand, environmental contributions to stability vary with age and are best approximated by a model with slopes before and after age 30. In very early childhood, the environment does not contribute to phenotypic stability (b0 = .034, p = .09), but the environmental contribution increases until age 30 (b0–30 = .008, p < .001) and plateaus afterward (b30–90 = .001, p = .21). The AIC preferred models contain substantially more complexity in terms of the number of free slopes that are required. However, visual inspection of Figure 5 indicates that the BIC and AIC preferred trend lines largely overlap. For the genetic contribution, the AIC preferred model implies that
