In psychology, (behavioral) epigenetics is the study of what role genetics and environment take in the shaping of behavior. This is chiefly the study of how nurture (upbringing and experiences) affects and shapes behavior (hereditary nature of the subject).
This is studied in real life by examining the traits of identical twins that were separated at birth and adopted into different homes and circumstances. Scientists who study this have found interesting contrasts and similarities in the form of food preferences, artistic tastes, extracurricular activities, and relationships. These are traits that on the surface wouldn't seem to be genetic in origin but research has shown evidence that these may be influenced by genes.
On another note, historians enjoy speculating on how various historical figures would have turned out in a different time, place, or set of circumstances. An example of this would be "What if Hitler had been raised with a kinder home life and in a time and place of less political turmoil; would he still have been the vicious psychopath that he became?" His upbringing and the circumstances of his life, combined with his basic "mental wiring" (for lack of a better term) caused him to be what he became. Through research, by studying how genetic behavior is shaped by experiences, psychologists can work to improve parenting and education so that more individuals can have fulfilling lives. All children are born with a basic nature; shy, aggressive, athletic, artistic, and academic traits for example. With better insight into these personality types, education and discipline can be shaped to have a maximum effect.