Personality (Lo, 2017) – Is Personality Genetic?

Boy laughing with dog, personality

Nebula Genomics DNA Report for Personality

Is personality genetic? We created a DNA report based on a study that attempted to answer this question. Below you can see a SAMPLE DNA report. To get your personalized DNA report, purchase our Whole Genome Sequencing!

Sample report for personality from Nebula Genomics
Sample variants for personality from Nebula Genomics

How much of human personality is controlled by genes is often described by the question: “Nature or Nurture?” The core of this question asks whether it is predetermined by a person’s genes or a result of environmental influences. In almost all cases, experts agree that it is a combination of both. However, there is continued debate as to how much each contributes. 

Temperament is a spectrum
This trait can be thought of as a spectrum. Wikipedia. CC-Attribution-Share Alike 4.0 International.

What is Personality?

An individual’s personality is extremely complex and generally considered as a combination of various traits. Others may think of it as how sociable a person is. The American Psychological Association defines it as differences in characteristic patterns of thinking, feeling and behaving.

Is Personality Genetic?

Psychological science has spent decades on the study of personality and whether it is more related to one’s genes or the environment. One of these studies was the Minnesota Study of Twins Reared Apart, which looked at 350 pairs of identical and fraternal twins between 1979 and 1999. The results suggest that twins share temperament traits whether they are raised together or apart, supporting the idea that at least some parts are genetic.

However, not all of the psychology of personality that develops could be explained by genetics, suggesting that as much as 80% of one’s personality is influenced by their direct environment.

Twin studies help scientists understand temperament differences. Wikipedia. CC-Attribution-Share Alike 3.0 Unported. 

Other twin personality testing, where 250 pairs of twins (123 identical and 127 fraternal) suggest that the Big Five trait theory described above has heritability estimates up to 40-60%. A single study published by Jang et al (1996) described the hereditary of conscientiousness, agreeableness, neuroticism, openness to life experience, and extraversion to be 44%, 41%, 41%, 61%, and 53% determined by genetics, respectively.

Many of the specific genes that are believed to play a role in the personality dimension are involved with communication between cells and the brain. MedLine Plus cites a number of genetic variants:

  • DRD2 and DRD4: Enhances the desire to seek out new experiences
  • KATNAL2: Associated with self-discipline
  • PCDH15 and WSCD2: Associated with sociability
  • MAOA: Introversion 

You can read more about current research in The Journal of Personality and Social Psychology.

Personality Disorders

These disorders are a type of mental illness that involves long term patterns of thoughts and behaviors that are largely unexpected and often lead to mental health problems, including difficulty in functioning in daily life and maintaining relationships. These disorders include difficulty in relating to other people and situations. 

These conditions usually start when people are teenagers or in their early adult years and can be difficult to diagnose. In time, they may become less noticeable as adults mature and learn to live with the conditions. 

There are many types and people may exhibit symptoms of one or more. They can be classified as eccentric (paranoid or schizophrenia), dramatic (antisocial, borderline, histrionic, and narcissistic), or fearful (anxiety or obsessive compulsive disorder).

The Big Five Model

The aspects of personalities are both healthy and diverse. Many experts rely on the certain traits to define an individual’s overall temperament. According to this theory of personality, the traits are on a spectrum, meaning that a person can fall from low to high on each trait and anywhere in between. They tend to remain stable throughout someone’s life and are both genetic and environmental, with up to 50% being controlled by genetic influence.

Agreeableness: how a person treats relationships with others. People with high agreeableness tend to show trust, altruism, kindness, and affection towards others.

Conscientiousness: ability to engage with thoughtfulness, good impulse control, and goal-directed behaviors. People with high conscientiousness appear goal driven and organized.

The Big 5 Personality Traits
Diagram of the Big Five traits. Wikipedia. CC-Attribution-Share Alike 4.0 International.

Extroversion: The extent to which someone seeks out relationships with their environment and with other people. Extroverts tend to appear sociable, outgoing, and talkative. The opposite of extroverts are introverts, or people who prefer to listen and appear more reserved or quiet in social settings. This is one of the major focuses of the Myers-Briggs type testing. 

Neuroticism: The overall emotional stability of an individual. It includes how likely a person is to see events as threatening or difficult. People with high neuroticism can be anxious and moody.

Openness: Willingness to try new things and engage in imaginative or intellectual activities. People with high openness tend to be more creative and artistic while those with low openness are more comfortable in routine. 

A person usually describes themselves as shy, sociable, or organized, as something that fits under one or more of these traits. It has been found that these traits may evolve slightly from childhood to adulthood but for the most part stay stable throughout a lifetime. 

Other popular approaches to personality include:

Humanistic perspective: The word personality is based on psychological growth, free will, and personal awareness. Carl Rogers suggests that people are inherently good and that free will drives most personality types. Another theorist on this perspective, Abraham Maslow, suggested that people are motivated by a hierarchy of needs where people focus their energy on the necessary components of life first (e.g. food, water) and once those are met, their personality characteristics become more focused on things like esteem.

Psychoanalytic perspective: This theory focuses on early childhood experiences and the unconscious mind. Sigmund Freud is one of the most well known theorists of this perspective. Neo-Freudian theorists, including Erik Erikson and Carl Jung agreed with Frued on certain aspects of the unconscious but disagreed with other major aspects of Freud’s theories. 

Summary of “Is Personality Genetic?”

Overall, it is largely understood that an individual is a combination of genetic components and environmental factors. The Big Five model provides a good overview of some of the most common traits that come together to form an overall temperament. Twin studies have demonstrated that anywhere between 20-60% is a result of heredity. This has been shown through detection of similar types in twins who were raised in different environments. There is not a clear pattern of inheritance, suggesting that this characteristic is the result of a complex interaction of many genes. 

If you liked this article, you should check out our other posts in the Nebula Research Library!