The origin of you: a tale of the nature and nurture of your personality

Illustration by Amelia Sadat

Fundamentally, you are the result of a unique combination of DNA and experiences. The ‘nature versus nurture’ theory has been around for decades, used by geneticists and psychologists to explain several human phenomena. More recently, there has been a focus on the origins of ‘personality’. Is the way we think, talk and act a result of the alleles we inherit, the events in our life, or both?

The word ‘personality’ originates from ‘persona’, the Latin for ‘mask’. In 2014 there was a viral twitter post about a Japanese proverb that is related to this idea. Apparently, we have three faces or masks; the one we wear for the world, the one we wear for our closest peers and finally the one we wear behind closed doors. While there has been no academic confirmation of this concept or its origins, it does not sound too eccentric. Indeed, in the age of social media influencers and celebrities, it should come as no surprise to us that people are not always who seem.

Thomas Aquinas brought about the novel notion of ‘tabula rasa’, that humans come into the world as a ‘blank slate’ upon which their identity is painted on, according to happenings in their life. Later, John Locke embellished this with the idea that people do indeed have freedom of identity, but their fundamental human nature is unchangeable. In light of Darwinism and the neurosciences, we now acknowledge that the brain has evolved to detect changes in the environment and in turn elicit an appropriate response. The only so called ‘blank slate’ we know of is in the neo-cortex, the part of the brain responsible for thought and decision. However, the amygdala, which is involved in your in-built primal instincts, has a strong influence over this. So, perhaps we are not as free in our character as we thought.

But is there anything in our DNA, the genetic blueprint of our being, that explicitly determines our character? While this is largely unexplored territory, some studies show that many genes may cooperate to bring about certain personality traits. For instance, there is evidence for a link between genes for Dopamine (a happiness hormone) and sensation seeking tendencies. It was reported that ‘Dopamine genes’ together account for approximately 6.6 percent of this behaviour in humans. Sensation seeking can, in extreme cases, lead to substance misuse and addiction disorders.

A behavioural geneticist at the Center for Regenerative Therapies, Dresden has unveiled a fascinating aspect of the origin of personalities. Professor Kempermann discovered that the development of character differences can be seen in a part of the brain called the hippocampus. In an experiment conducted in a rodent arena, mice that explored the environment extensively over a three-month period grew more neurones than less adventurous, genetically identical mice.

In other words, your early explorative interactions with the world around you, even in a world shared with seven billion people, may set you apart from the rest. This may explain why even identical twins born in the same household develop minute personality differences early on, and perhaps why parents are able to tell their twins apart.

But the tendency to seek new sensations is only a fragment of one’s character. ‘OCEAN’ is a model in psychology that refers to the ‘Big Five’ traits that build up an individual’s personality: openness (how curious you are), conscientiousness (how self-disciplined you are), extroversion (how outgoing you are), agreeableness (how cooperative you are), and neuroticism (how emotionally stable you are). Assuming that these characteristics are measurable on a continuous scale, it is almost impossible that two people will have the exact same character score.

So, what does all of this mean? Well, in those moments when you feel most dull and average, sub-par even, know this: statistically speaking, no one in the world thinks, speaks or acts as you do. Truly, you are unique.