A while ago, in Psychology class, our teacher’s daily lecture was on the classic psychological debate of Nature versus Nurture. Do our genes impact our personality or are we an Aristotelian tabula rasa, or blank slate? While a connection could be seen inherently through this psychological concept’s usage of biological premises, a connection was easily seen between Psychology and Biology after my teacher displayed a Punnett Square, a common sight in genetics as a way to explain the transfer of genotypes from parents to offspring. As I recalled previous lessons from Freshman year on genetics, I couldn’t help but contemplate whether or not the theory had any validity.
Dr. Michael Kraus, assistant professor of Organizational Behavior at Yale, says it’s complicated. Historically, he said, psychological studies would focus on twins, and compare self-reports from fraternal twins, those of which share around 50% of the genes, and identical twins, who share 100% of their genes. In these studies, they found that the amount of variation in personality that is explained by genes, or heritability, was around 46% for identical twins, and around 23% for fraternal twins, showing a very clear suggestion that genetic influences had a noticeable impact on personality. The problem is finding what genes specifically impact factors like personality, preferences, intelligence, or physical characteristics.