Personality Psychology

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Personality psychology is the study of how personality develops. One of the largest and most popular psychology branches , researchers in this area also strive to better understand how personality influences our thoughts and behaviors.

Personality psychologists often look at how personality varies from one individual to the next, as well as how it may be similar. These professionals may also be tasked with the assessment, diagnosis, and treatment of personality disorders.

Your unique personality makes you who you are; it influences everything from your relationships to the way you live. Learn more about what personality is, the theories surrounding its development, how personality is tested, and what it means to have a personality disorder.

What Is Personality?

What is it that makes you who you are? Many factors contribute to the person you are today, including genetics, your upbringing, and your life experiences.

Many would argue that what makes you unique is the characteristic patterns of thoughts, feelings, and behaviors that make up your personality . While there is no single agreed-upon definition of personality, it is often thought of as something that arises from within the individual and remains fairly consistent throughout life.

Personality encompasses all of the thoughts, behavior patterns, and social attitudes that impact how we view ourselves and what we believe about others and the world around us.

Understanding personality allows psychologists to predict how people will respond to certain situations and the sorts of things they prefer and value. To get a sense of how researchers study personality psychology, it will be helpful to learn more about some of the most influential personality theories.


A number of theories have emerged to explain the aspects of personality. Some are focused on explaining how personality develops, while others are concerned with individual differences in personality.

Trait Theories of Personality

The trait theories of personality center on the idea that personality is comprised of broad traits or dispositions. Various theories have been proposed to identify which attributes are key components in personality, as well as attempts to determine the total number of personality traits .

Psychologist Gordon Allport was one of the first to describe personality in terms of individual traits. In his dispositional perspective, Allport suggested that there are different kinds of traits: common, central, and cardinal.

Common traits are shared by many people within a particular culture. Central traits are those that make up an individual's personality. Cardinal traits are those that are so dominant that a person becomes primarily known for those characteristics.

An example of a cardinal trait is Mother Teresa. She was so well-known for her charitable work that her name became almost synonymous with providing service to those in need.

Allport suggested that there were as many as 4,000 individual traits. Psychologist Raymond Cattell proposed that there were 16. Cattell also believed that these traits exist on a continuum and that all people possess each trait in varying degrees.

A psychologist named Hans Eysenck would narrow the list of traits further, suggesting there were only three: extroversion, neuroticism, and psychoticism.

Today, the "Big Five" theory is perhaps the most popular and widely accepted trait theory of personality. The theory proposes that personality is made up of five broad personality dimensions:

  • Agreeableness
  • Conscientiousness
  • Extroversion
  • Neuroticism
  • Openness

The Big Five theory states that each trait exists as a broad continuum. An individual's personality will fall somewhere on the spectrum for each trait.

For example, you might be high in extroversion, conscientiousness, and agreeableness, but somewhere in the middle for openness and neuroticism.

How Personality Develops and Changes Through Life

Freud's theory of psychosexual development is one of the best-known personality theories—but also one of the most controversial. According to Freud, children progress through a series of stages of personality development. At each stage, libidinal energy (the force that drives all human behaviors) becomes focused on specific erogenous zones.

Successful completion of a stage allows a person to move on to the next phase of development. Failure at any stage can lead to fixations that can impact someone's adult personality.

Erik Erikson, another psychologist, described eight psychosocial stages of life. With Erikson's theory, each stage plays a significant role in the development of a person's personality and psychological skills.

During each psychosocial stage, an individual will face a developmental crisis that serves as a turning point in their development. Successfully completing each stage leads to the development of a healthy personality.

Erikson was more interested in how social interactions influenced the development of personality. He was primarily concerned with the development of what he called ego identity.

While Freud's theory suggested that personality is primarily formed and set in stone at an early age, Erikson believed that personality continued to develop throughout life.

How Personality Is Tested

To study and measure personality, psychologists have developed personality tests, assessments, and inventories. The tests are widely used in a variety of settings. For example, the famous Myers-Briggs Type Indicator (MBTI) is frequently used as a pre-employment screening assessment.

Other assessments can be used to help people learn more about different aspects of their personalities. Some tests are used as screening and evaluation tools to help diagnose personality disorders.

Gaining a better understanding of your personality can be helpful in many aspects of your life. For example, relationships with friends, family, and coworkers might improve when you become aware that you work well with others or that you need to make time to be alone.

You have probably encountered a selection of personality tests online (for example, an online quiz that tells you whether you are extroverted or introverted ). Some of these tests purport to reveal the "real you," while others are clearly meant only for entertainment.

Personality assessments that you take online should be taken with a grain of salt. Informal tools can be fun and might offer some insight into your preferences and characteristics, but only personality tests administered by trained and qualified professionals should be used as formal assessments or to make a diagnosis.

Personality Disorders

Personality psychologists are also interested in studying problems with personality that may arise. Personality disorders are characterized as chronic and pervasive mental disorders that can seriously impact a person's thoughts, behaviors, and interpersonal functioning.

The current edition of the Diagnostic and Statistical Manual of Mental Disorders ( DSM-5 ) lists 10 personality disorders, including antisocial personality disorder, borderline personality disorder, narcissistic personality disorder, and obsessive-compulsive personality disorder.

The National Institute of Mental Health (NIH) reports that approximately 9.1% of the adult population in the United States experiences symptoms of at least one personality disorder each year.

Being diagnosed with a personality disorder can be distressing, but you should know that there are treatments. Working with a mental health professional, you can learn to recognize the difficulties that these disorders can cause and explore new coping strategies.

It is OK to feel frightened and concerned about what the future might hold but remember that you do not have to face it alone. There are people who are trained, skilled, and ready to help you take the next steps in your treatment.

Depending on your specific diagnosis, your doctor might recommend psychotherapy, skills training, medication, or a combination of all three.

Work closely with your healthcare team to develop a treatment plan that focuses on your needs and goals.

A Word From Verywell

Personality is a broad subject that touches on nearly every aspect of what makes people who they are. There are many ways to think about personality. There are some theories that focus on individual traits and those that consider the different developmental stages that take place as personality emerges (and sometimes changes) over time.

Psychologists are not only interested in understanding normal human personality, but in recognizing potential personality disturbances that might lead to distress or difficulty in key life areas. By being able to identify problems people have at home, school, work, or in their relationships, psychologists are better able to help people develop skills to cope and manage the symptoms of personality disorders.

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.
  • McCrae RR, Costa PT. Validation of the Five-Factor Model of Personality Across Instruments and Observers. Journal of Personality and Social Psychology . 1987;52: 81-90.

  • National Institute of Mental Health. Prevalence: Any Personality Disorder .

By Kendra Cherry
Kendra Cherry, MS, is the author of the "Everything Psychology Book (2nd Edition)" and has written thousands of articles on diverse psychology topics. Kendra holds a Master of Science degree in education from Boise State University with a primary research interest in educational psychology and a Bachelor of Science in psychology from Idaho State University with additional coursework in substance use and case management.