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Nature vs Nurture - what does science say?


We have all heard of the nature vs nurture argument. For the longest time, scientists have had their own theories about where our personalities come from.

People have been divided about whether it is nature or nurture that shapes who we are. This has led to the promotion of eugenics (a set of beliefs and practises that aim to improve the genetic quality of a human population), leading to actions such as selective breeding, sterilisation, and in the case of the Nazi’s, wholesale murder.

As can be seen from what was mentioned above, this has been a very controversial topic for a very long time and can greatly affect one’s perspective on the world and how they act on their beliefs about the people around them.

So, what makes a person extroverted? What makes every single one of our personalities different? This article is going to be a deep dive into whether nature or nurture plays a bigger part in who we become as people.

Types of Traits:

According to the big five model, personality is composed of five broad traits. Individual personalities may be high, low, or somewhere in between each of the five core traits. The five traits are:

  • Agreeableness: prosocial behaviours like trust, altruism, kindness and affection

  • Conscientiousness: high levels of thoughtfulness, good impulse control, and goal-directed behaviours

  • Extroversion: sociability, talkativeness, assertiveness, and excitability

  • Neuroticism: sadness, moodiness, emotional instability and worries about different things

  • Openness: creativity, open to trying new things and happy to think about abstract concepts

Most of the words used to describe a specific person would fall under one of these broad headings, and it is these that are thought to be the building blocks of who we are.

Genes vs Environmental Causes:

So comes the big question. Researchers have spent decades researching families, twins, adopted children and foster children in search of an answer to the big question.

We all know that both nature and nurture can have an effect on our personalities, but which one plays a bigger role? Most large-scale twin studies suggest that genetics play a huge part in who we are - one of these studies is the Minnesota Study of Twins Reared Apart.

This study consisted of studying 350 pairs of twins between 1979 and 1999. These included both identical and fraternal twins, and twins who were both raised together and apart. These results revealed that personalities of identical twins were similar whether they were raised in the same household or apart, suggesting genetics influences some aspects of our personalities.

However, this doesn’t mean that the environment doesn’t play a role in shaping our personalities - some studies suggest that identical twins share approximately 50% of the same traits, while fraternal twins only share 20%.

Plomin draws similar conclusions, hypothesising that the key to our personalities does not lie in how we were brought up by our parents, but rather what we have inherited from them genetically. He finds that 50% of the psychological differences between us are accounted for by our genetic heritability, while the other 50% is accounted for by the environment. However, he argues that most of the latter 50% is made up by unpredictable events, and that of the environmental influences that can be moderated, most of it is an expression of genetics.

Changes in Personality Traits:

When it comes to the broad, dominant traits in a person, change tends to be difficult - when it occurs, these changes are very subtle. Here are two examples:

  • An extraverted person may become somewhat more reserved over time. This does not mean that they have become an introvert: this just means that the person’s extroversion has modified over time. The person is still outgoing, but may find that they enjoy solitude on occasion.

  • An introverted person may find themselves becoming more social as they grow older. This again, does not mean that they have become an extrovert: this just means that the person is beginning to enjoy social events even more and find them less draining.

In these examples, the individual’s core personality has not changed altogether, but rather the central traits experience a subtle shift, often as a result of experiences.


Despite having spent billions of dollars on personality research, no definite answer to this question has been found yet. Instead of holding extreme nativist or nurturist views, most researchers are now interested in investigating how nature and nurture interact in different ways. This has led to the emergence of epigenetics, which shows how environmental influences may affect the effect that our genes have on us.

Recent research is showing more and more that nature is the biggest contributor to who we are. This is not to say that nurture does not play a part - personality traits are complex, suggesting that they are formed by many different factors, which interact in many ways to form our individual personalities.

This is a long debated argument that still requires further medical discoveries to be answered. What are your views on this?


Researcher - Charissa


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