What is Personality Psychology? Every Definition of Human Personality Included

Alexander Tokarev, PhD
Updated on: February 20, 2024
Reviewed by:
Yelnur Shildibekov, PhD

What is Personality?

While there is no single agreed-upon definition, most psychologists agree that personality is made up of relatively stable traits over time.

This agreement is largely reflected in the historical definitions of personality provided by prominent psychologists and summarized below. Further, our personalities are often thought to be shaped by a mix of interacting internal and external factors, including our genetics, environment, culture, and upbringing.

Definitions of Personality






The universe of traits, ideally covering all aspects of personality, or at least sampling them with even density. Traits are thus points or, rather, small areas on the continuous but finite surface which represents all the observed behavior of the individual.



The sum-total of the actual or potential behaviour patterns of the organism, as determined by heredity and environment



A person’s unique pattern of traits; any distinguishable, relatively enduring way in which one individual differs from others



A dynamic organization, inside the person, of psychophysical systems that create the person’s characteristic patterns of behaviors, thoughts, and feelings. Personality is biologically determined, but its expression is dependent upon the environmental forces



One’s habits and usual style



[A set of traits representing] a psychological (therefore) organismic structure underlying a relatively enduring behavioral disposition, i.e., a tendency to respond in certain ways under certain circumstances

American Psychiatric Association


[A collection of] traits [that] are defined as enduring patterns of perceiving, relating to, and thinking about the environment and oneself that are exhibited in a wide range of social and personal contexts



A collection of relatively enduring patterns of thoughts, feelings, and behaviors



A collection of traits formed by density distribution of states, whose activation is dependent upon various socio-cognitive factors (e.g. goals, beliefs, motivations etc)



A relatively stable and enduring tendency to behave in a particular way



An individual’s characteristic patterns of thought, emotion, and behaviour, together with the psychological mechanisms – hidden or not – behind those patterns

Larsen & Buss


The set of psychological traits and mechanisms within the individual that are organized and relatively enduring and that influence his or her interactions with, and adaptations to, the intrapsychic, physical, and social environment

Pervin et al


Characteristics of the person that account for consistent patterns of feelings, thinking and behaving



An individual’s unique variation on the general evolutionary design for human nature, expressed as a developing pattern of dispositional traits, characteristic adaptations, and integrative life stories complexly and differentially situated in culture



The organized developing system within the individual that represents the collective action of that individual’s major psychological subsystems

Costa and McCrae


Consistent and enduring individual differences in ways of thinking, feeling and acting



Personality traits are the relatively enduring patterns of thoughts, feelings, and behaviors that reflect the tendency to respond in certain ways under certain circumstances



A recurrent tendency to show a particular observable behavior in a particular type of situation



The coherent patterning over time and space of affect, behavior, cognition, and desire



A set of probabilistic descriptors of relatively stable patterns of emotion, motivation, cognition and behavior, in response to classes of stimuli that have been present in human cultures over evolutionary time

Why is Personality Psychology Important?

Predict Behavior

Understanding personality helps psychologists to predict how we might behave in certain situations and why.

A more accurate understanding of behavioral patterns can help predict many outcomes ranging from educational attainment and job performance to life satisfaction and eating habits.

Explain Behavior

Understanding personality psychology also helps to explain our emotional reactivity, motivations, and decision-making processes.

Ultimately, understanding personality can provide insight into ourselves and those around us, leading to better relationships, improved communication skills, greater self-awareness, and personality development.

Understand Personality Disorders

Personality psychology helps mental health professionals to understand personality disorders better – whereby an individual has difficulty relating to others and adhering to social norms due to extreme variations in thoughts, feelings or behaviors.

Examples of Personality Disorders include Borderline Personality Disorder (BPD), Narcissistic Personality Disorder (NPD), and Avoidant Personality Disorder (APD). By understanding these conditions through the lens of personality psychology, mental health professionals can offer better support and treatment plans for those suffering from them.

What Do Personality Psychologists Do?

Personality psychologists study and analyze personality traits to better understand why we behave the way we do.

From biological influences such as genetics to environmental factors such as culture and upbringing, a personality psychologist examines all the different elements in our lives that shape our personalities and make us unique. Typically, personality psychologists are skilled researchers and practitioners, trained to apply a combination of qualitative and quantitative methods.

Theories of Personality

Big Five Personality Trait Theory

The Big 5 Theory, also known as the Five Factor Model (FFM), is one of the most widely used theories of personality psychology. The model is based on decades of research and explains how the following five core traits manifest within individuals.

Each of these traits is a continuum, meaning that people can fall anywhere on the spectrum from low levels to high levels of each trait. If you would like to see how high or low your score is on each trait, take our free Big Five Personality test.

Psychoanalytic Theory

The main premise behind Psychoanalytic theories is that unconscious thoughts, emotions, and early childhood experiences significantly influence human behavior and mental processes.

The most prominent figure in this field, Sigmund Freud, emphasized the significance of the unconscious mind, the role of early childhood experiences in shaping personality, and the structure of the psyche, comprising the id, ego, and superego.

Also famous for creating the theory of psychosexual development, Sigmund Freud proposed that personality is shaped by biological needs and instincts expressed in different stages of development. Freud's theory states that how we respond to those needs during childhood will impact our behavior and relationships later in life.

How is Personality Tested?

Personality is typically measured by self-report methods, including personality tests, questionnaires, or inventories.

These methods are used to quantify an individual's personality traits, providing valuable information and insights into how someone thinks, feels, and behaves in different contexts.

Usually, personality inventories provide a number of statements and require a person to mark their level of agreement on a scale, ranging from 'strong disagreement' to 'strong agreement'.

Frequently Asked Questions:

How Can Personality Change Throughout Life?

While Personality is made up of relatively stable traits over time, it can still gradually change over time, albeit in predictable ways. For example, research shows that Neuroticism tends to slowly increase as we age and its levels eventually plateau later in life.

Considering the psychoanalytic approach, Erik Erikson's psychosocial stages provide a framework for understanding how personality develops throughout life. His theory proposes that individuals go through eight distinct stages of development, each with its own challenges and opportunities. During each stage, individuals learn how to cope with the different demands of life by developing specific skills and traits.

What are Personality Disorders?

Personality disorders in Psychology are a type of mental health disorders that can severely impact how someone thinks, perceives, and relates to the world around them. Habitual behavior patterns can severely disrupt an individual's ability to complete everyday tasks and are often unnoticed by the person affected.

Understanding how people behave can be the key to improving overall mental health. Drawing upon a growing body of research in Personality Psychology, Clinicians have gained invaluable knowledge about human behavior that helps them identify, diagnose and address invisible ailments such as depression or anxiety.

Additionally, research has shown that certain personality traits are associated with an increased risk of developing psychological disorders such as schizophrenia or bipolar disorder if left untreated. As such, mental health professionals need to understand how personality affects physical and mental well-being to provide appropriate interventions when needed.

The Diagnostic and Statistical Manual of Mental Disorders-5 (DSM-5 TR) is an invaluable tool for diagnosing both mental and personality disorders. To aid in correct diagnosis, the PID-5 was created - a comprehensive assessment that measures maladaptive personality traits outlined by the DSM-5 TR.

The PID-5 is used to measure a number of personality traits such as Irresponsibility, Manipulativeness, Deceitfulness, and Grandiosity (Krueger et al., 2012). With the combination of DSM-5 TR and PID–5, healthcare professionals are more equipped to objectively identify common symptoms associated with diagnosed conditions.