according to the theory of gene-environment interaction, people who inherit certain traits tend to seek out life experiences that reinforce those characteristics. The most low-reactive kids, for example, court danger from the time they’re toddlers, so that by the time they grow up they don’t bat an eye at grown-up-sized risks. They “climb a few fences, become desensitized, and climb up on the roof,” the late psychologist David Lykken once explained in an Atlantic article.
