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introversie psychologie
Are introverts born or made?
Karolien Koolhof •
When we talk about introversion, we quickly end up in a classic debate: is it nature (your genes) or is it nurture (your upbringing and environment)? We often view it as a scale, but modern science shows that this idea is fundamentally outdated. The scale simply doesn't exist.
In modern genetics (specifically epigenetics), genes and environment are no longer seen as two separate competitors. They actually work together. Imagine your genes not as an unchangeable blueprint, but as a giant control panel with millions of light switches. Your environment (how much stress you experience as a child, the tranquility in your home, the expectations at school) functions as the hand that flips certain switches 'on' or 'off'.
Without the hand, the switch does nothing. There is no nature without nurture. You are not either born this way or made this way. You are a continuous process of your biology reacting to your environment.
Nature
Why do we actually want to know so badly what percentage of our introversion is 'innate'? Often, there is an unspoken assumption underlying this: we are trying to justify ourselves. In a society that frequently rewards extroversion (speed, loudness, action), we sometimes use nature as an excuse. "I can't help that I can't handle the open-plan office; I was just born this way."
By doing this, we unconsciously still approach introversion as a flaw in our individual system that we need to explain scientifically. But let's let go of the nature/nurture debate entirely for a moment. What if introversion isn't an individual trait at all?
Twins
But where do we get those persistent percentages, then? You often read in popular psychology magazines that introversion is "about fifty percent genetically determined". Historically, these figures lean heavily on classic twin studies. But there is a huge blind spot there.
These studies compare identical and fraternal twins and are based on the so-called equal environments assumption. The researchers assume that both types of twins are exposed to the exact same environmental factors. In practice, this is an illusion. Identical twins look physically identical to each other, are therefore treated exactly the same by their environment more often, and elicit much more similar reactions than fraternal twins. They essentially create their own, highly overlapping nurture.
Furthermore, the way we measure is fundamentally flawed. The standard questionnaires that determine whether someone is an introvert often measure behavior that we label as 'withdrawn' in our Western society. Imagine: a child is in an overwhelming, loud classroom and wisely decides to retreat quietly to a corner. On paper, this child scores high on introversion. But at that moment, are we measuring an innate neurological blueprint, or are we measuring a perfectly logical, cultural survival strategy in a toxic environment? We often confuse cultural reactions with neurological hardwiring.
Group
What if we completely let go of the idea that introversion is a purely individual trait? From the perspective of evolutionary anthropology, you could argue that traits do not exist for the individual, but for the survival of the entire group. Hundreds of thousands of years ago, a tribe needed hunters who sprang into action directly, impulsively, and without too much fear. We now call that extroversion.
But a tribe consisting only of fast, extroverted risk-takers wouldn't survive the very first harsh winter. There was an absolute, vital need for the watchful, thoughtful, deep thinkers. The people who stayed at the edges of the camp, recognized complex patterns in the seasons, foresaw dangers from afar, and conserved precious energy. Introversion.
Introversion and extroversion together form an ecological balance. In that light, introversion is not a personality type that happens to reside in your individual brain at all. It is a relational role. An essential ecological function. You are not an introvert purely for yourself; you fulfill a necessary function for the neurodiversity and the success of the collective.
Observer
A concrete example of how this is misunderstood is sending the introverted professional to assertiveness training. We teach them tricks to be more visible in meetings and to speak up faster. In other words: we put in a lot of effort trying to turn the thoughtful observer into a mediocre, loud hunter.
This demonstrates a total lack of understanding of how human ecosystems work. An innovative team, just like a successful tribe, needs balance. As soon as we reduce the introverted employee to an individual defect that needs to be 'fixed' or 'taken into account because of their nature', we rob the organization of exactly what it needs: thoughtful analysis, risk mitigation, and deep reflection.
The next time you are completely drained after an hours-long, chaotic brainstorming session and desperately wonder whether this exhaustion is due to your genes or your upbringing, realize this: stop placing the blame on yourself. Your brain is not broken. It is doing exactly what it was designed to do by tens of thousands of years of evolution, interacting with an open-plan office that simply makes far too much noise. So it is high time we design work environments where not everyone has to be the loudest hunter to be considered indispensable.
About the author
- Karolien Koolhof is a coach voor introverts and gifted individuals
- Author of the book Introvert Leadership
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