In a Passive genotype-environmental effect, the genetically related parents provide a rearing environment that is correlated with the genotype (genetic makeup of an organism) of the child. A child's environment is correlated with their genes, which correlate with their parents' genes because he or she is making decisions likely from their own preferences. Passive genotype-environmental effects cannot interpret the direction of effects in parents-child interaction, but also cannot interpret the cause of those effects in biologically related families. An example of a passive genotype-environment can be found negatively in sports. Parents who are skilled track runners faced with a child who is not learning to do sports let alone run track, may provide a more enriched environment for the less able child than for another who acquires track skills quickly. Infant children cannot do as much niche building and seeking out as older children, therefore passive genotype-environment effects are less important to older children who can extend their experiences beyond the family's influences. Older children can create their own environments to a much greater extent. The effects of passive genotype-environment effects wane, or diminish gradually, when the child has many extra familial opportunities.
An Evocative genotype-environmental effect represents different responses that different genotypes evoke from social and physical environments. It is quite likely that smiley, active babies receive more social stimulation than sober, passive infants. For example, cooperative, attentive preschoolers receive more pleasant and instructional interactions from the teachers or adults around them than uncooperative, distractible children.
Active genotype-environment effect, "niche-building sort", is arguably the most powerful connection between people and