Results from the correlated influences model are shown in Table 3. Additive genetic (25%), shared (33%) and non-shared environmental influences were responsible for individual differences in PSI and for RSI (A=42%, C=24%, E=34%). Composite genetic influences in RSI were attributable to those overlapping with PSI (genetic correlation of 0.43) and those specific to it. Shared environmental influences on RSI were completely overlapping with PSI (Δχ2=0.07 for 1 df constraining specific C on RSI to zero). Non-shared environmental influences on RSI were largely specific, however, a modest yet significant correlation of 0.11 (Δχ2=6.61 for 1 df constraining overlapping E to zero) was noted. Thus, under the correlated influences model, total covariation between RSI and PSI was attributable to overlapping genetic, shared and non-shared environmental factors.
