Are Personality Traits Genetic?

Different personality traits help make people unique
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Personality traits help make us unique individuals, but not everyone agrees on exactly how many different traits exist or what factors contribute to these characteristics. Is personality genetic, or does the environment play a greater role in shaping who were are?

Both genetics and environment play a part in the development of personality, although the specific degree to which each one plays a part often depends on the specific personality trait in question.

This article discusses how personality traits are defined, whether personality is genetic, and how traits can sometimes change over time.

What Are Personality Traits?

Traits are typically defined as the different characteristics that make up an individual's personality.

Personality Traits

Personality traits are relatively stable patterns of thoughts, feelings, and actions that distinguish people as individuals.

Trait theory suggests that our personalities are made up of a number of different broad traits. For example, extroversion (often known as extraversion) is a personality dimension that describes how people interact with the world. Some people are very extroverted and outgoing, for example, while others are more introverted and reserved.

In the past, it was believed that personality traits changed very little over the course of a lifetime. Some longitudinal studies have revealed that traits are more nuanced than previously believed and that some personality changes can and do occur over time.

Genes vs. Environmental Causes

What matters more when it comes to personality, nature or nurture? Just how much does your DNA influence your personality? Researchers have spent decades studying family, twins, adopted children and foster families to better understand how much of personality is genetic and how much is environmental.

Both nature and nurture can play a role in personality, although large-scale twin studies suggest that there is a strong genetic component.

This certainly does not mean that the environment does not play a role in shaping personality. Twin and adoption studies indicate that human personality is around 30% to 60% heritable.

Personality traits are complex, and research suggests that genetic and environmental factors shape traits. These two forces interact in various ways to form our individual personalities.

One of the best-known longitudinal studies looking at the heritability of personality characteristics, the Minnesota Study of Twins Reared Apart, has long been cited as evidence that traits are primarily inherited. However, one recent critique has called the results into question by noting that important data about the control group was excluded from publication.

A 2018 study published in the journal Molecular Psychiatry concluded that interactions between more than 700 genes had a greater influence on certain personality traits than cultural and environmental influences.

Are People Born With Certain Personality Traits?

Kids display early signs of their personality in the form of temperament, which is estimated to be 20% to 60% due to genetics. Children generally have one of three basic temperaments: easy, difficult, or slow-to-warm-up.

But how much does childhood temperament influence personality later in life? A child's basic temperament is important in determining how they interact with their environment. Because of this, these different interactions contribute to different experiences.

While your temperament, or disposition, influences your personality, they are not the same and can be quite different. Your temperament affects how you behave and how you interact with your environment. Your personality, on the other hand, encompasses your beliefs, thoughts, traits, characteristics, and behaviors that develop as you age.

Recap

Your temperament includes the basic dispositional traits that you are largely born with. It is temperament that influences how you behave, your social interactions, and how you respond to the environment. Such experiences then play a part in shaping the development of your personality.

Types of Traits

What would you say if someone asked you to list the personality traits that best describe you? You might rattle off a variety of traits such as kind, aggressive, polite, shy, outgoing, or ambitious. If you were to make a list of every personality trait, it would probably include hundreds or even thousands of different terms used to describe different aspects of personality.

Psychologist Gordon Allport once created a list of personality traits that included more than 4,000 terms.

The question of just how many personality traits there is has been the subject of debate throughout much of psychology's history, but many psychologists today rely on what is known as the big five model of personality.

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

The five traits that make up personality are:

  • Agreeableness: trust, altruism, kindness, affection, and other prosocial behaviors
  • Conscientiousness: high levels of thoughtfulness, good impulse control, and goal-directed behaviors
  • Extroversion: sociability, talkativeness, assertiveness, and excitability
  • Neuroticism: sadness, moodiness, emotional instability, worries about many different things
  • Openness: creative, open to trying new things, happy to think about abstract concepts

Most of the characteristics you might use to describe your own personality fall under one of these broad headings. Personality traits such as shy, outgoing, friendly, and sociable are aspects of extroversion, while traits such as kind, thoughtful, organized, and ambitious would be part of the conscientiousness spectrum.

Research indicates that heritability explains around 40% to 60% of the variance in big five personality traits.

Each of these five traits represents a continuum. Some people are low in certain traits and high in others. In fact, many people are somewhere in the middle of many or most of these characteristics.

Personality Trait Changes

When it comes to some of the broad, dominant traits, change tends to be difficult. When it does occur, these changes tend to be very subtle.

A very extroaverted person, for example, might become somewhat more reserved over time. This does not mean that they will transform into an introvert. It simply means that a subtle shift has occurred, and the person's extroversion has been slightly modified. The individual is still outgoing and gregarious, but they might find that they also enjoy solitude or more quiet settings on occasion.

Research suggests that people do tend to become more introverted as they grow older.

In both of these examples, the individual's core personality trait has not changed altogether. Instead, changes over time, often the result of experiences, have led to subtle shifts in these central traits.

Principles of Personality Traits

Researchers have also suggested that a number of basic principles have emerged from investigations into personality.

  • Identity development principle: People develop a stronger identity as they age and maturity brings a greater commitment to and maintenance of this sense of self. During the younger years of life, people are still exploring different roles and identities. As people age, they begin to feel stronger loyalty to the identity they have forged throughout their life.
  • Maturity principle: People tend to become more agreeable, emotionally stable, and socially dominant as they grow older.
  • Plasticity principle: While personality traits tend to be stable, they are not set in stone. They are subject to environmental influences at any stage of life.
  • Role continuity principle: It is the consistency of roles that leads to continuity in personality traits rather than consistency in environments.

Recap

Consistent roles in life play a part in maintaining the stability of personality, but personality traits can also change throughout life. Personality changes somewhat with age, as people develop stronger identities and become more emotionally stable.

A Word From Verywell

While research suggests that genetics play an important role in personality, it is also important to recognize that other factors do have an influence. In many cases, the environment influences the expression of genes.

Personality tends to be fairly stable, but that doesn't mean it is etched in stone. Instead, certain factors, including age and identity, impact how personality shifts and changes over time.

11 Sources
Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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Additional Reading
  • Bouchard, T.J. Jr, Lykken, D.T., McGue, M., Segal, N.L., Tellegen, A (1990). Sources of human psychological differences: the Minnesota Study of Twins Reared Apart. Science. 1990; 250(4978):  223–228.
  • Matthews, G., Deary, I.J., & Whiteman, M. C. Personality Traits. Cambridge: Cambridge University Press; 2010.
  • Roberts, B.W., Wood, D., & Caspi, A. The development of personality traits in adulthood. In O.P. John, R.W. Robins, & L.A. Pervin (Eds.), Handbook of Personality: Theory and Research, pp. 375-399. New York: The Guilford Press; 2008.

By Kendra Cherry
Kendra Cherry, MS, is an author and educational consultant focused on helping students learn about psychology.