If you’ve been an author for any length of time, you’ve probably heard about the Myers-Briggs Type Indicator. Maybe you’re enthralled with it. Maybe you’ve glanced at the confusing muddle of letters and given up deciphering it. Or maybe you’ve heard others talk about it. Whatever the case, if you aren’t acquainted with MBTI, welcome to your introduction to personality types.

Although other personality tests and categories exist, MBTI is one of the most popular. With eight letters in pairs of two (Introvert or Extrovert, iNtuitive or Sensing, Feeling or Thinking, Perceiving or Judging) and sixteen possible combinations, the range is comprehensive without being overwhelming.

This topic is fascinating for those of us who enjoy delving into other people’s minds, but do personality types have practical applications in writing, and what are the limitations?

The Uses of Personality Types

A character is a character first, not a type. Like people, every character can’t be packed into one of sixteen simple boxes. Each character is influenced by his past, surroundings, and relationships. Sometimes a character’s personality is so twisted that the original type becomes obscured, yet it still undergirds how he processes the world around him.

Introversion/Extroversion

The first of the four pairs is the Introvert/Extrovert classification, which affects the central world of a character. Introverted characters concentrate on their internal world. They will recharge in solitude before venturing out and connecting with people. Some introverts might be painfully shy, while others are more outgoing. Introverts just happen to prefer their own company. They will recede into their inner world if the outer chaos becomes unbearable.

On the other hand, extroverts focus on the outer world and are energized by socialization. They’re more likely to consort with reckless companions because they enjoy surrounding themselves with people.

Sensing/Intuition

The Sensing/iNtuitive distinction shows how a character gains information. Sensors are rational and practical. They rely on concrete evidence and base their plans on factors they can see and hear and feel.

Conversely, iNtuitive characters perceive the world through patterns, impressions, and ideals. As dreamers, they will be more interested in the principles and abstract arguments and theories behind events. They believe there are exceptions to everything and might go with a gut feeling even when reality seems against it.

Thinking/Feeling

Thinking versus Feeling governs how characters make decisions. Thinkers will weigh the pros and cons of a situation instinctively and try to be as impersonal as possible, possibly to the extreme of appearing heartless. Although they do experience the pull of emotions, they view it as an unsound basis for a decision. So they suppresses their feelings to study the problem as logically as possible.

In contrast, feelers are more concerned about the personal aspect. They will act on what they feel is right, taking their own emotions and the emotions of others into consideration. They may rush into a solution without thinking the whole situation through. Logic will probably be consulted as well, but it is not the sole foundation on which their decisions rest. Their focus is more on the people involved and what is best for them than on hard facts.

Judging/Perceiving

The final set of letters determines how a person interacts with the world around them. Judgers keep life moving. They will drive the story, charging ahead to figure things out and draw conclusions on matters. They enjoy leading and may need to be restrained and forced to work with others.

Perceivers, however, tend to let life happen. As characters, they need to be given a reason to press forward. They are apt to be open to new ideas and options while they wait to see what will transpire.

The Limits of Personality Types

Whatever the personality type of a character, each trait can have varying degrees of intensity. One character might be very introverted and dislike being around people at all. Another might straddle the line between introversion and extroversion, enjoying people but still refreshing herself by being alone.

Remember that a character’s personality type doesn’t dictate how he acts as much as how he processes information. Situations will penetrate the heart of a feeler first, but that doesn’t mean she won’t force herself to analyze the issue impersonally. Or, a thinker might abandon logic and release an emotional outburst. Characters will have a wide range of reactions depending on the circumstances, but pinpointing their personalities and how they view the world is a great way to understand them better.

Although personality types do influence how characters think and behave, characters are more complex than that. Sometimes a character will flip to an opposite type while under stress. Another might act contrary to stereotypes due to past experiences. For example, an extrovert who was once betrayed might be more reserved and unfriendly than an introverted character.

Personality types will help lend consistency to your characters’ actions, but don’t cling to them at the expense of what makes your characters come alive. Their friends, family, and enemies. Their pasts. The trials they have suffered. Their ghosts and their dreams. All of this forms the window through which they see life.

Integrating Personality Types with Theme and Character Arcs

Your theme shouldn’t revolve around character types, but the characters you’ve created probably coordinate with your theme, and the message or lesson you’re teaching is likely an area they struggle with. In a current work in progress, one of my characters who learns to trust and surrender to God is an INTJ. Although any character could (and might need to) learn this lesson, it’s harder for INTJs because this type wants to be in control, understand what is occurring, and be able to change events. Being helpless and forced to trust will be more difficult for them than for another type, such as an ISFJ.

Breaking characters is yet another method for tying personality types into theme and plot. Watching a loved one get injured or killed could break many characters, but it will most upset characters who thrive on being in control (like INTJs). Some types can be broken merely by being ignored, while others can be broken if they’re pressured to commit a wrong. You don’t need type-specific events to break your character, but if you are working on your climax or trying to determine what will hurt them the most, this is a perfect place to start.

You’ll also be able to use a character’s personality type to define what pleases and irritates him, and what sort of flaws he will wrestle with. This partly depends on your characters, but because of the under-wiring of various types, certain things will affect some characters more than others. Any person can struggle with pride, but some types (like an ESTJ) will struggle with listening to others more than an ESFJ or ISFP. The structured schedules and charts an INTJ loves will drive an INFP or ENFP crazy. Some types enjoy hugs, whereas others tend to avoid physical touch. Some hide their emotions, and others display them without shame. Some enjoy teasing, some hate it, and others simply don’t get it. The list could go on and on.

To Use or Not to Use

You’re probably already familiar with how your characters think and react, but personality types take you deeper, allowing you to see through their eyes and view the world in a new light. In the end, it’s up to you to decide whether to study the types long enough to implement them in writing. Although it’s not a must-know for every writer, a foundational knowledge of personality types is worth the effort—and it’s an intriguing topic, with insights to understanding characters and people in general.