Personality Traits

Do you think of yourself as an extrovert or introvert? Rigorously organised or laid-back? Whether you're confident or shy, outgoing or quiet, your personality type is in-part influenced by your genetics. While environmental factors and life experience influence our personalities, genes also contribute to forming our personality type.

Personality is often broken down into five main areas, known as the ‘Big 5’. These areas are extraversion, neuroticism, agreeableness, conscientiousness and openness. Each of these traits has been associated with a number of genetic variants, indicating that the genes we carry have the potential to influence our behaviour [1] Jump to reference section: [1] . However, it’s important to remember that there is no single strong genetic marker for any of the personality traits explored in this report and that genes can only hint at the characteristics we’re more likely to display.

Extraversion

All of us behave differently when faced with social choices, which can have far reaching consequences for how we make our life decisions! People who are extraverted tend to be comfortable around other people, start conversations and don’t mind being the centre of attention. They may show characteristics such as being talkative, bold and energetic.

Certain genetic variations influence the likelihood of extraversion, a few of which will be explored here. There is plenty of evidence showing that dopamine, a hormone and neurotransmitter, is linked to having an extrovert personality [2] Jump to reference section: [2] .Dopamine acts as a reward signal and is released when the brain is expecting something pleasant to happen. A key part of the dopamine system in our brain is involved in motivation, emotion and reward, which in turn is linked to extroverted behaviour. In extroverted people the dopamine pathway in the brain is activated more often, so individuals with this personality type tend to experience strong positive emotions more frequently [3] Jump to reference section: [3] .

Openness

People with the trait of ‘openness’ are quick to understand things, have a vivid imagination and are likely to seek out a variety of experiences and try new things. People with high levels of openness are more comfortable with the unfamiliar and open to novelty. Individuals with this personality type are often associated with characteristics such as curiosity, intelligence and creativity.

Research shows that a second pathway in the dopamine system (which reflects the difference between openness and extraversion) is associated with cognitive exploration and openness, which in-turn is linked to flexibility of thinking.

A number of genetic variants have been associated with a higher likelihood of openness, some of which are explored below [4] Jump to reference section: [4] .

Agreeableness

People with this trait tend to be interested in other people, sympathise and make people feel at ease. Agreeable people are often described as cooperative, polite, kind and friendly.

Serotonin, a neurotransmitter known to many as the ‘happy chemical’, has been linked to agreeable personality traits, with research showing that high serotonin levels have a positive correlation with agreeable characteristics.

Variation in genes linked to the serotonin pathway are partly responsible for the link between serotonin production and ‘agreeable’ personality traits. People with specific genetic variants (some of which are explored below) have a higher chance of being agreeable and show characteristics such as being warm, generous and trustworthy.

Neuroticism

People with this trait are more likely than average to experience emotions such as anger, anxiety, self‐consciousness, irritability, emotional instability and nervousness. While we are all likely to experience these emotions at some points in our lives, people with elevated levels of neuroticism experience these emotions more regularly and at a higher level than most [5] Jump to reference section: [5] .

Low levels of the ‘happy chemical’ serotonin are associated with an increased likelihood of exhibiting neurotic characteristics. People with specific genetic variants (some of which are explored below) are more likely to experience lower levels of this neurotransmitter which is closely linked with activating the pleasure and positivity pathways in our brain.

Conscientiousness

People with high levels of conscientiousness tend to be prepared, diligent, pay attention to details and do what they say they will. This trait reflects the tendency to be responsible, organised, hard-working and goal focused.

Similarly to agreeableness, the neurotransmitter serotonin is associated with conscientious personality traits. Serotonin is associated with stable emotions and motivation, as it acts to stabilise information in our brain and enable us to focus on our goals. High serotonin levels have been associated with high motivational stability and can result in conscientious personality traits. People with specific genetic variations (some of which are explored below) have a higher chance of being conscientious and display characteristics such as being careful and practical [6] Jump to reference section: [6] .

Conclusion

While numerous genetic variants have been linked to these five personality types, it is important to remember that there is no single strong genetic marker for any of the personality traits explored in this report. Environment, socio-economic factors, life experiences and life-style choices all play a significant role in forming and evolving our personalities.

Ultimately, our genes alone cannot reveal our personality but may hint at the kinds of behaviours we are more likely to display.