What Is Personality Psychology? (Including Theories)

By Indeed Editorial Team

Published 5 May 2022

The Indeed Editorial Team comprises a diverse and talented team of writers, researchers and subject matter experts equipped with Indeed's data and insights to deliver useful tips to help guide your career journey.

An individual's personality influences how they interact with the world around them and their perception of it. A psychologist who specialises in the study of personality strives to understand these very factors that influence individual characteristics and help people understand their personalities, enabling them to make informed decisions. Learning about personality psychology can assist you in deciding if a career path in this field is desirable to you. In this article, we explain what personality psychology is and why it's important and go over different kinds of personality theories and assessments.

What is personality psychology and why is it important?

Personality psychology is a branch of psychology that explores the factors that comprise an individual's personality and how they differ from one person to another. Psychologists use different methods of research to investigate the origins of personality and its impact. Understanding the elements that influence personality can help us understand a person's behaviour. A researcher in this field identifies specific traits and functional aspects of personality that have practical applications. For example, they create personality assessments that can help diagnose and treat personality disorders.

Related: 11 Top Jobs for a Psychologist (With Job Details and Salary)

What is the definition of personality?

Personality is a pattern of characteristics, including thoughts, feelings, attitudes and behaviours, which influence how a person interacts with others. Our environment, genetics and upbringing may influence the development of an individual's personality. Some of how an individual's personality impacts their life include their behaviour in specific situations, the thoughts they express and how they develop and maintain relationships. Many consider personality to remain consistent over the course of a person's life but may be susceptible to change caused by certain life experiences, such as traumatic events.

Different theories of personality

Here are some of the different theories of personality:

Type A and Type B personality theory

This theory is based on two distinct categories of personality types labelled as Type A and Type B. People with a Type A personality are competitive and outgoing and often have a strong sense of urgency. Individuals with Type A personalities may be potentially at risk for heart disease and hypertension. Individuals with Type B personalities are tolerant and relaxed and usually experience lower levels of stress and anxiety.

Psychoanalytic theory of personality

The psychoanalytic theory emphasises the impact of the subconscious on our behaviour and divides personality into three components:

  • Id: This is the unconscious and impulsive part of the personality that seeks gratification.

  • Ego: This component of personality is cognisant of the environment and moderates the id's demands.

  • Superego: This component reflects societal morals and values that control the id personality.

The ego mediates between the id and the superego. The balance of the interactions between these three components comprises a person's personality and influences their behaviour.

Humanistic theory of personality

The humanistic theory of personality is based on the concept that free will determines behaviour, subjective experiences and motivation to fulfil a hierarchy of needs and achieve self-actualisation. A person's self-concept comprises their real self, ideal self and self-esteem. The real self is how a person sees themselves, whereas the ideal self is the person they want to become. The more similar the real and ideal selves are to each other, the more likely one is to self-actualise. Self-esteem refers to how a person values, likes and accepts themselves.

Social cognitive theory of personality

The social cognitive theory of personality explains that social, cognitive and behavioural factors, such as environments, thoughts and actions, interact with one another to influence personality, which is a phenomenon called reciprocal determinism. This theory suggests that modelling behaviours through observation of others have a significant impact on shaping personality. This theory also emphasises the impact of self-efficacy on the development of personality, which is a person's belief in their own ability to succeed at achieving a specific goal.

The Big Five personality trait theory

The Big Five personality trait theory suggests a grouping of personality traits characterise how a person may think, feel and behave. It specifies five distinct categories for which the traits lie along a spectrum. Variances in range within each category and the combinations of these variances constitute an individual's personality. Here are the five categories:

Openness to experiences

This trait refers to willingly having new experiences, being curious and engaging in intellectual pursuits. Scoring higher in this trait may indicate creativity and adventurousness. Scoring lower may indicate a preference for a routine, traditional and practical way of thinking.


Conscientiousness refers to an individual's ability to be diligent, exercise self-discipline and aims to achieve goals or expectations. Highly conscientious people are usually efficient, systematic and reliable. Those who score lower may be more impulsive in their behaviour, displaying flexibility and openness to change.


Extraversion refers to the degree to which a person is sociable, outgoing and assertive. People who score high in this trait are extroverts who enjoy meeting new people, having a wide social circle and engaging in conversations with others. Scoring low indicates introversion, where a person prefers solitude, solitary activities and listening to others.


This category describes a person's ability to be socially harmonious, compassionate and trusting of other people. A high score indicates that one is friendly, compliant and altruistic. Those who score lower are more self-focused, competitive and ambitious.


Neuroticism is a trait that refers to a person's emotional sensitivity. When an individual scores higher in neuroticism, it may mean that they have a greater degree of self-awareness, take fewer risks and may experience more stress. Individuals who score lower tend to be emotionally stable, confident and resilient and are more relaxed and able to handle stress.

What are personality tests?

A personality test is one of many tools to assess an individual's personality and diagnose disorders in clinical settings and is useful for employers looking for candidates with specific personality types or traits. There are two categories of personality tests, being objective or self-reporting and projective tests. Objective tests typically involve reading through questions or statements and rating them on a scale. Projective tests involve presenting ambiguous pictures or scenarios and asking respondents to interpret them.

Examples of personality tests

Here are examples of projective and objective personality assessments:

Myers-Briggs Type Indicator (MBTI)

This introspective and objective questionnaire assigns an individual to one of 16 personality types. This questionnaire is based on the theory that people relate to the world and others through four psychological areas of sensation, intuition, feeling and thinking, with one area being dominant. The test typically assesses participants across four areas:

  • Extroversion (E) and Introversion (I)

  • Sensing (S) and Intuition (N)

  • Thinking (T) and Feeling (F)

  • Judging (J) and Perception (P)

The test results then assign the participant to one of 16 personality types, which is any combination of the four pairs, such as ESTJ and INFP. The MBTI test can help assess a person's career suitability, leadership potential and understanding of organisational issues.

Related: 10 Careers for INFJ Personalities (With Duties and Salaries)

16 Personality factors questionnaire

This questionnaire focuses on 16 separate personality traits that can objectively explain differences in an individual's personality. The applications of this test include career assessment, employment selection and clinical assessment of personality disorders. The 16 personality factors are abstractedness, apprehension, dominance, emotional stability, liveliness, openness to change, perfectionism, privateness, reasoning, rule-consciousness, self-reliance, sensitivity, social boldness, tension, vigilance and warmth.

Related: What Is a Psychometric Test and How to Prepare for It

Rorschach test

The Rorschach test consists of ten cards containing inkblots of various shapes. Five inkblots are black and grey, two cards have black, grey and red, while three cards contain other colours except black. The examiner presents each card and asks an individual to provide their interpretation. After recording answers for all the cards, the examiner shows the cards a second time to confirm the examinee's answers. The examiner then interprets the answers using the Exner scoring system, which sometimes aids the diagnosis of personality and other psychiatric disorders.

Thematic Apperception Test (TAT)

This projective test is similar to the Rorschach Test but involves cards depicting ambiguous characters and scenes. The complete test involves 32 cards that examiners can use selectively. The examiner presents a card and asks the participant to dramatise it by describing:

  • what led to the events in the card

  • what's currently happening in the scene

  • the characters' thoughts and feelings

  • the outcome of the story

There are multiple methods to score a participant's responses. Therapists use the TAT to help clients express their feelings, to identify emotional problems and to assess personality disorders.

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