Social and self selection processes are closely related to genotype-environmental correlations in biology which describe non random distributions of environments among different genotypes. In other words, `at risk' genotypes get or create more than their fair share of `at risk' environments. If expanded to include at risk `phenotypes', then this concept is in line with the causal CU→PDG model in which genetic and environmental risks in CU also increase the risk of individuals seeking out and affiliating with similarly inclined peers.
