Welcome back! In this series, we’re exploring the good, the bad, and the ugly of personality tests. So far, I’ve covered some reasons the Myers-Briggs (MBTI) and Enneagram have questionable value , why people often resonate with their results anyway , and introduced the Big Five , a scientific model of personality (if you haven’t already, you can test yourself here ). This final installment will explain why the Big Five perform better and stand up to the criticisms of other tests.
1. They were developed using the scientific method.
In contrast to the MBTI and Enneagram, whose systems were derived from untested philosophies instead of rigorous observations of people, the Big Five and the theories used to explain them were developed based on careful, scientific observation. Carl Jung, the psychologist whose theory inspired the MBTI, was a psychoanalyst who turned his assumptions about human nature into a taxonomy; in other words, he made up a system of organizing personality that corresponded to his ideas without testing whether they actually described humans’ personalities. The researchers who discovered the Big Five took the opposite approach and let data drive the way they understood personality organization.
Some of the earliest such studies investigated the lexical hypothesis: if there are characteristics on which people differ, and if understanding those differences is important for understanding and interacting with people, any culture will have created a word in its language to describe each of those characteristics. There are about 4,500 words in the English dictionary that describe personality traits —consistent patterns of thoughts, feelings, and behaviors. Through analyzing people’s ratings of themselves and others on these traits using a statistical technique called factor analysis, which groups characteristics together based on how strongly they’re related, researchers found five major clusters of related characteristics that describe a majority of our individual differences. Then they began developing and testing theories to explain how we get these traits.
2. Continuums are better than categories.
The MBTI and Enneagram give you a personality type —a discrete category that is qualitatively different from other categories. The Big Five are personality traits , or individual characteristics measured on a continuum from low to high.
Psychologists prefer traits to types. One reason is that types are a collection of multiple traits. The ISFJ type description includes qualities like quiet, responsible, and considerate. These represent three different dimensions of the Big Five—extraversion, conscientiousness, and agreeableness—yet they’re all lumped together in this category. Big Five scales assess them separately and with more nuance. Also, because types often include multiple traits, there is overlap in personality types, and a person may see themselves in multiple types.
Additionally, type approaches categorize people as extremes, when in reality, human qualities are better represented by a continuum, with more of us in the middle than at the ends. This principle is demonstrated in the way the Big Five are measured, with questions using a sliding scale rather than a forced-choice format.
3. They can show how you’ve changed.
With a personality type, it is difficult if not impossible to measure your personality on different occasions and find out how much your personality has changed. If you look back at yourself 5, 10, or 20 years ago, you will be able to see some ways that you are different. Sometimes those changes are subtle, and sometimes they are large. The research supports this “anecdata”; in addition to unique ways you change as an individual, humans tend to change in similar ways as they get older . The ability of personality types to account for those meaningful changes is dubious.
The first time I took the MBTI, it was about 2004, and I scored as an INTJ. I can tell you specific ways that I have changed in the 15 years since then—some major, some minor. However, if I took the test again today, I might or might not see that change reflected in my results. In the first post, we talked about how the MBTI assigns you a type; for example, if you score anywhere in the upper half of the extraversion spectrum, you get an E, and in the lower half, an I. Depending on what my original score was, I might cross the threshold into E territory, or I might not. It’s even odds that the change I’ve experienced isn’t captured at all by my type. But if it does register a change, I’d suddenly appear to be a totally different type of person.
Personality trait dimensions capture change much better than types. By measuring individual traits on a continuum, you can see whether you have changed on certain characteristics and exactly how much. If I scored a 50/100 on openness to experience as a college freshman and a 72 today, I can see that I have increased quite a lot in openness. My other personality traits may have changed in that time, too, in small ways or large ones, or perhaps not at all.
By looking at my personality trait profile, I can see whether, like most people, I have increased on conscientiousness, agreeableness, and emotional stability from age 20 to 35, or whether I’m pretty similar to the me of five years ago, but for my level of openness. Test-retest reliability tends to be strong over short intervals and decreases with time, which represents actual personality change rather than poor measurement.
4. They predict things that personality should predict.
If your personality leads you to approach the world in characteristic ways, we would expect it to be related to the choices you make and what happens in your life, right? As we discussed in the first post, one of the issues with the MBTI is that it doesn’t predict many of the types of outcomes it claims to be related to.
Yet, across an astounding number of studies, the Big Five have been shown to predict satisfaction with life , education and academic performance , job performance and satisfaction , relationship satisfaction and divorce , physical health , health-related behaviors , and how long people live , and more. Personality correlates with these things even after accounting for the effects of intelligence, socioeconomic status, and other important variables .
5. It’s (NOT) all about the Benjamins, baby!
One common criticism of systems like the MBTI, Enneagram, DISC, and other commercially available tests is that they can cost a lot of money. The Enneagram is a bargain at $12, but to take the MBTI online through their website as an individual, you’ll have to cough up $49.99. Although you can find Big Five tests that are pay-to-play, like the NEO inventories, most are free and available on the web where anyone, researcher or layperson, can use them. Many personality psychologists are proponents of openness and transparency in their research, and that includes making assessment instruments available to the public.
So why haven’t I heard about this before?
In a nutshell, we got it, but we haven’t flaunted it. Most personality researchers are just that—researchers—and are much more interested in and skilled at scholarship than they are at marketing. As such, we haven’t done a great job at advertising our findings to the general public. Testing companies have been very successful in selling their models because they have to be to make a profit.
While the Big Five are scientifically valid and capture a great deal of the human experience, they only measure what Gordon Allport called “common traits,” characteristics that you can compare across individuals. They do not account for everything that makes us unique—our tendency to stop and move turtles out of the road, our particular brand of wit, our love of all things autumn, or other quirks—but no test can. They also don’t cover some other things that make you you: motivations, emotions, values, beliefs, talents, and dark traits . However, personality psychologists examine these variables, too.
Finally, most of the work on the Big Five have been done using Western samples. The evidence for whether the same five factors work the same way in other cultures is mixed, but it’s one of the big questions we’re currently tackling.
I hope you’ve enjoyed the series and had some fun examining your personality traits!