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Understanding the 4 personality types: A, B, C, and D

Talent Assessment | 6 Min Read

Understanding the 4 personality types: A, B, C, and D


Our personality serves as the architects and artists of our lives. It influences our reactions to experiences and the outcomes we achieve. One’s personality is the lens through which they perceive the world, shaping their thoughts, behaviours, and interactions. Understanding these personality types, often Type A, B, C, and D, sheds light on how we approach challenges, communicate, and make choices.

Many psychologists, researchers, and enthusiasts have studied and refined the concept of personality types over many decades. While no single framework captures the full complexity of the human character, these four distinct personality types offer valuable insights into our core tendencies and preferences. Understanding these personality types aids in self-discovery and personal development. It is a bridge to improved empathy and communication and helps gain a deeper appreciation for the unique qualities in people.


4 basic temperaments

The origin of the four personality types goes back to more than two thousand years. In ancient Greece, Hippocrates termed the types of personality after body fluids: choleric, melancholic, phlegmatic and sanguine. These four temperaments were said to be based on the humoral medicine theory and have persisted under different interpretations and adaptations throughout history.


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The choleric temperament is linked to an excess of yellow bile, one of the four humours. Individuals with a choleric temperament are considered assertive, competitive, and ambitious. They are natural leaders and are often quick to make decisions and take charge of situations. Cholerics are considered extroverted and driven by a desire for control and power.



The melancholic temperament is associated with an excess of black bile. People with a melancholy temperament are considered introverted, reflective, and analytical. They are deep thinkers and compassionate individuals prone to introspection and self-analysis. Melancholics are often associated with artistic and creative tendencies.



The phlegmatic temperament is connected to excess phlegm, another bodily fluid. Those with a phlegmatic temperament are considered calm, easygoing, and content. They are described as stable, patient, and good-natured. They are peacemakers who prefer avoiding conflict and maintaining a harmonious environment.



The sanguine temperament is linked to an excess of blood. People with a sanguine temperament are considered outgoing, social, and cheerful. They are often seen as extroverts who enjoy socializing and are quick to make friends. Sanguines are thought to be optimistic and lively individuals who approach life with enthusiasm.


Personality types

The ABCD personality type was introduced in the 1950s by two cardiologists named Meyer Friedman and Ray Rosenman. Initially, it consisted of Type A and Type B personalities. However, they have been expanded to include personality Type C and Type D. It categorizes individuals into 4 personality types. This is based on their behaviour, attitudes, and responses to stress.

Four categories of personalities have been given various names and designations. But generally, they are called Type A, B, C, and D personalities. Each individual is a blend of these four personality types.


Type A personality

People with Type A personalities are achievement-oriented and are perfectionists. They are prone to experiencing stress, can be impatient, and have a sense of time urgency. They have high standards and are highly competitive. They love to set goals and achieve as many as possible. Essentially, they are driven, but they can sometimes appear aggressive. Type As are inspiring and reliable people; they push boundaries and explore outside their comfort zone.

Type A personalities at work are characterized by good delegation and administrative skills. They prefer to work independently and set their schedules. They also have valuable problem-solving skills and show productivity.


Type B personality

People with a Type B personality are easygoing and relaxed. They are less likely to experience stress and are patient, creative, and imaginative. Type B people tend to be grounded and peaceful. They make people comfortable; people tend to like being around them. They are compassionate; they know how to read other people’s emotions and understand how they should be there for others and themselves.

Type B personalities at work are spontaneous, enthusiastic and outgoing. They are good at interacting with customers and enjoy working in teams. They thrive in collaborative situations.


Type A vs. Type B personality

Having different kinds of people on a team who get along well is essential because this helps the company succeed. Type A and Type B are two different personality styles. Type A personalities like to plan for the future and are focused on goals. Type B personalities are more easygoing and care about getting along with others in the present. A team with a mix of Type A and Type B personalities works well. Type A personalities help the team stay on track, and Type B personalities build good relationships. While Type B people often get their motivation from others, Type A people remain motivated independently. Understanding both personality types is vital to ensure that the team works well together.

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Type C personality

People with a Type C personality are analytical, detail-oriented, and focused on accuracy. They are likely to experience emotional stress. Type C personalities focus on tiny and technical details. They are introverted and reserved in interactions. They like routines, prefer a set lifestyle, and desire order, logic, and precision.

Type C personalities at work are logical, prepared, and outcome-driven. Type C personalities prefer clearly defined job roles and expectations. It helps them prioritize tasks and see them through to completion.


Type D personality

People with a Type D personality are introverted and keep their emotions to themselves. They are sensitive and are not very optimistic. They look for security and are resilient, great at giving advice, and are the kind of people who do not give up.

Type D personalities at work are cautious and task-oriented. They are motivated by routine and stability. They are organized and often prefer a calm working atmosphere.


Type X personality

Type Xs have more than one personality. Each type is in equal ratio to the other and is often identified as a Type Ax/Bx, where ‘x’ refers to the intersection between two different personality types.

Some people have four balanced personality types. They are also considered Type X personalities. Type X personalities are adjustable to changing circumstances.


Other personality types and theories

The historical concept of the four basic temperaments remains a critical part of the history of psychology and personality theory. In contemporary psychology, the study of personality has evolved significantly, with various models and theories providing an evidence-based understanding of human personality. Personality types can be broadly categorized into four types or over sixteen combinations.

Personality type models vary in their approaches, and one popular system that uses four personality dimensions is the Myers-Briggs Type Indicator (MBTI). MBTI categorizes individuals into sixteen personality types based on four aspects: extraversion/introversion, sensing/intuition, thinking/feeling, and judging/perceiving. It provides insights into how people perceive the world and make decisions.

In contrast, other personality models, such as the Big Five, also known as the Five Factor Model, focus on five broad dimensions of personality: openness, conscientiousness, extraversion, agreeableness, and neuroticism (OCEAN).


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This model is well-regarded for its empirical support and scientific basis, providing a nuanced and comprehensive view of personality. Each dimension represents a continuum rather than a binary choice, making it a more flexible and accurate tool for understanding personality differences. Ultimately, the choice between these models depends on the depth and complexity of understanding one seeks in exploring human personality.





Personality is complex and influenced by multiple factors, including genetics, upbringing, and life experiences. Each personality type brings its unique characteristics and tendencies to the forefront, shedding light on how individuals navigate the complexities of life, work, and relationships. Identifying various personality types is challenging, but recognizing changes in personality types over time is possible.

Understanding these personality types is a valuable self-awareness tool, allowing individuals to recognize their strengths and weaknesses. It helps appreciate the diversity of human nature, foster empathy and effective communication. Personality tests can be used for growth and self-reflection. Ultimately, acknowledging and embracing the nuances of personality types builds more robust and inclusive communities.



What are the characteristics of Type B personality?

What is the Type A and B personality scale?

Originally published November 8 2023, Updated November 8 2023

Written by

Archita Bharadwaj has worked as a Content writer at Mercer | Mettl since April 2023. With her research background, she writes varied forms of content, including blogs, ebooks, and case studies, among other forms.

About This Topic

Personality assessments are a method of identifying candidates whose characteristics match the role and organization’s requirements. Personality assessments help HRs make effective people decisions by placing people in positions suited to their disposition.

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