The Science Behind the Five Major Personality Types

From a lecture series presented by Professor Mark Leary, Ph.D.

Let’s talk about the five major personality types. The English language contains more than 3000 words that refer to personality characteristics of various kinds. This shows the extent to which we all spend thinking about and talking about people’s personality characteristics. But having all of these words actually creates a problem for studying and understanding personality.

Isolating The Five Major Personality Types

Clearly, there aren’t really 3000 different personality characteristics. Many of these words—in any language—are synonyms or near-synonyms for the same traits. So, if someone is nervous a great deal of the time, we can say that they’re a nervous person or we can say that they’re anxious or they’re tense or that they’re neurotic. These words might have slightly different shades of meaning, but they all refer to basically the same characteristic.

With so many different words that refer to personality characteristics, researchers have faced a serious challenge in trying to figure out how many basic personality traits there really are. What are the big five personality traits?

Learn more: What Is Personality?

This has been a surprisingly difficult task, and it’s made even more challenging by the fact that not all personality traits are created equal. Some characteristics are more important than others in understanding people’s behavior and in predicting important outcomes in people’s lives, such as the nature of their relationships with other people, the degree to which they’re successful at achieving their goals, their psychological well-being, and their health.

To understand a person’s behavior knowing how dependable and honest they are is more useful than knowing whether they’re tidy or excitable.

For example, it usually tells you more about what a person is like to know whether they’re dependable or honest than it is to know whether they are tidy or excitable. Dependability and honesty are simply more important, more informative characteristics than tidiness and excitability are. They account for more variability in people’s behavior, and they have more important implications for people’s lives.

If we want to understand a person’s behavior and the choices they make and how they get along with other people, knowing about how dependable and honest they are is more useful than knowing whether they’re tidy or excitable.

Psychological Researchers and Factor Analysis

When psychological researchers started to tackle the question of basic personality traits in the 1930s and 40s, they turned to what was then a newly-developed statistical procedure called factor analysis. Factor analysis is a statistical technique that can be used to identify the basic dimensions that underlie a set of variables that are correlated or related to each other. I’m not going to explain how factor analysis works mathematically, but I do want you to understand what it does because it’s important for understanding basic personality traits.

Factor analysis is a statistical technique that can be used to identify the basic dimensions that underlie a set of variables that are correlated or related to each other.

Imagine that we asked a large number of people to rate themselves on, say, 100 characteristics that describe various aspects of personality. So they rate themselves on words such as enthusiastic, critical, dependable, anxious, reserved, sympathetic, careless, calm, outgoing, assertive, creative, maybe even excitable.

We could have people rate themselves on all 100 of these characteristics on a 5-point scale that ranges from “Not at all” to “Extremely.”

Now imagine that we correlated people’s ratings on each pair of these 100 characteristics. A correlation is a statistic that tells us how strongly 2 variables are related to each other. For example, across all of our respondents, we could calculate the correlation between people’s ratings of how enthusiastic they are and how assertive they are. And this number, this correlation, would tell us how strongly people’s ratings of enthusiasm are related to their ratings of assertiveness.

We could then calculate a correlation between every pair of those 100 ratings—that’s 4950 different correlations that give us a picture of how strongly each of these 100 characteristics is related to each of the other characteristics.

If we look at all of these correlations among people’s ratings of the 100 characteristics, we’ll find that some of the characteristics correlate highly with each other, while other characteristics don’t.

Learn more: Traits That Shape How You Think

For example, how people rate themselves on the characteristic, “dependable,” probably correlates pretty highly with how they rate themselves on the characteristic, “organized.” People who are dependable also tend to be organized, and people who are undependable also tend to be disorganized. So these 2 ratings of dependable and organized will probably correlate highly with each other.

When you find that ratings on one characteristic are highly correlated with ratings on another characteristic, a reasonable conclusion is that these 2 ratings are tapping into the same basic trait. If people who rate themselves highly on X consistently rate themselves highly on Y, then perhaps X and Y aren’t really 2 different things at all, but rather 2 ratings of the same general characteristic.

Now, if we were actually looking at a table of 4950 correlations among people’s ratings on 100 characteristics, we wouldn’t be able to make much sense of things, but that’s where factor analysis comes in. Factor analysis takes information about how all of these ratings correlate with each other and mathematically determines how many basic traits are actually being measured. So, factor analysis has been an indispensable tool for identifying basic personality traits from the hundreds of words that we use to describe personality.

Factor analysis takes information about how all of these ratings correlate with each other and mathematically determines how many basic traits are actually being measured.

The “Big Five”

By the 1980s, a high degree of consensus had emerged that human personality is characterized by only 5 basic personality traits. These 5 traits became known as “The Big Five”, and they’ve been the focus of an incredible amount of research. Many other traits exist, but these 5 have become recognized as the most important traits for understanding people’s personalities and behavior. But, before we talk about these 5 traits, I want to be clear about exactly what a personality trait is.

What is a Personality Trait?

As psychologists use the term, a personality trait is an internal, psychological characteristic that involves the tendency to respond in a particular way.

Think about your own behavior: Do you tend to be outgoing or more reserved in social situations? You probably aren’t either one all the time—sometimes you’re more outgoing, and sometimes you’re more reserved. But if we followed you around and watched you in many different situations, we’d probably find that you show a tendency to lean one way or the other.

You might tend to be more outgoing, or you might tend to be more reserved. The fact that you show a particular tendency in how you respond across situations suggests that you possess some psychological characteristic, or perhaps a set of characteristics, that predisposes you to react in one way or another. So, we would say that you have a trait that predisposes you to tend to be outgoing or reserved or whatever.

So, by definition, the concept of a trait implies that a person will show a certain degree of consistency in his or her thoughts, feelings, or behaviors across different situations.

If you have a particular trait, we ought to be able to see a tendency for you to respond in a particular way across different situations. Of course, even when people have a trait, they don’t act the same way all the time. Different situations call for different kinds of behaviors, and people who act exactly the same way all the time don’t adapt to the demands of specific situations.

No matter how outgoing you are, you must sometimes be reserved; and no matter how reserved you usually are, situations sometimes require you to be sociable. So, nothing in the concept of trait implies that a person acts the same way all the time. In fact, that would be a sign of a personality disorder. Again, having a trait simply means that people show a tendency to respond in a particular way.

…having a trait simply means that people show a tendency to respond in a particular way.

The concept of trait also implies a certain degree of consistency over time in how people tend to respond. People’s personality traits can and do change over time, at least within limits. But over the short run, we see stability in their traits. If you tend to be outgoing this month, we aren’t likely to find that you have become consistently reserved a few months from now. It can happen, for example, if people experience a traumatic event. But under normal circumstances, personality shows a good deal of stability over time.

Learn more: Consistency and Stability of Personality

The Difference Between a Personality Trait and a Personality Type

As I just explained, a trait can be visualized as a dimension or a continuum, and people can fall anywhere along the trait dimension from very low to very high. And when psychologists measure any particular trait, people’s scores can range from very low scores to very high scores. In the case of sensation-seeking, for example, scores on one measure of sensation seeking can range anywhere from 0 to 40.

In contrast, when we talk about a personality type, we are categorizing people into a small number of discrete categories or groups, sometimes only two. So, instead of giving you a score on a continuous measure of sensation-seeking, we could simply classify you as being low or high in sensation-seeking. Or, we could classify you as a dominant or submissive person, as depressed or not depressed, or as an extrovert versus an introvert.

In each case, we have classified you as a type of person—a low sensation seeker, a dominant person, an introvert, or whatever—by putting you in a category.

Personality researchers almost never talk about types because true personality types almost never exist.

Personality researchers almost never talk about types because true personality types almost never exist. That is, there are not many psychological characteristics in which people naturally and cleanly fall into one category or another. Instead, people vary from one another across all levels of a trait continuum.

You and I might both be low in sensation-seeking, but maybe you’re much lower than I am, and researchers want to measure and explain that difference. Putting both of us in the low sensation-seeker box throws away a great deal of information and nuance that’s important in understanding people’s behavior.

What is The Myers-Briggs Indicator Test?

Many people have taken the Myers-Briggs Type Indicator at some point in their life. The Myers-Briggs is used a great deal to help people understand their own personality, particularly in work organizations to help employees understand how they differ from their coworkers. It helps people recognize differences in how people approach situations and problems and thus helps people work together more effectively.

But the Myers-Briggs Type Indicator is, as its name indicates, a type indicator. It basically tells you what type of person you are on 4 characteristics: extrovert vs introvert, sensing versus intuition, thinking versus feeling, and judging versus perceiving. You don’t need to understand what those terms mean, but after people take the Myers-Briggs, they get a 4 letter code that tells them which of 16 types they are.

If you have taken the Myers-Briggs, you can probably remember your type—you’re an ISTJ or an INFP or an ESTP or whatever. And that code reflects your type.

As a way to provide people with insights about their own and other people’s personalities, the Myers-Briggs is quite useful. It not only gives people insight into their own personality, but it also helps people understand others. So, once I realize that a coworker and I have different approaches to the world—that we’re different types—I can work within those differences rather than just assume that the coworker is being obstinate, or doesn’t like me, or is mentally unbalanced.

And part of the Myers-Briggs’ usefulness in the workplace lies in its type-based approach. For practical purposes, it’s easier for people to think in terms of types of personalities rather than in terms of traits on a continuum. However, for scientific understanding, not only do types badly misrepresent the nature of personality, but the characteristics measured by the Myers-Briggs don’t easily map onto the basic personality traits that have been uncovered by personality research. So, although it’s a practical tool, personality researchers rarely use the Myers-Briggs Type Indicator.

Now that you have a sense of what a personality trait is, let’s take a look at the 5 basic traits that researchers have uncovered.

Keep Reading: Extroverts vs. Introverts: The Big Five Personality Types Explained

 

From the lecture series Why You are Who You Are: Investigations into Human Personality taught by Professor Mark Leary, Ph.D.