Figure 4.

Visualization of the theory that the phenotypic expression of genetic variation is constrained and enhanced by environmental opportunity. The small upside-down cup imposes a glass ceiling effect, such that there is an attenuated association of genotypes with phenotypes imposed by restrictive environments. For some phenotypes a restricted environment may be beneficial (e.g., reducing the risk of developing health disorders), whereas in other cases it will limit an individual’s chances to self-actualize genetic propensities (e.g., attaining more education).