Indexed by heritability quotient range from 0 to 1. 1 means trait is influenced solely by inheritance and 0 means trait is not influenced by inheritance: out of 83 births, approx. Environments produce similarities b/n people with no genetic similarity: the nature of nurture. In studies of more than 10,000 twin pairs: mz twin r = . 86, dz twin r = . 60, mz twins remain alike whether they are raised together or raised apart, heritability = 50, environment. Because our genes influence how we react and interact with the environment (genotype-environment correlation: genes influence our traits which influence our behaviors which have an influence on our environments. Example: genetic influences account for about 40% of the variance in scores from the home observation for measurement of the. Infancy (20%: childhood (40%, adulthood ( 80%, heritability quotient is not a fixed identity and the heritability of, development, why does heritability increase? a trait varies over age.