Even a Psychology Professor at Wharton gets the MBTI wrong!

The other day, when researching the MBTI personality test,  I came across this article on psychologytoday.com by Adam Grant, Ph.D., a professor at Wharton and the author of Give and Take. Adam argues that the MBTI is a fad that deserves no real merit as it is an unreliable, inaccurate, and uncomprehensive instrument. It’s nothing new that the MBTI receives criticism despite being one of the most (probably the most) widely practiced personality archetypes. And I’m not surprised when critique comes from a highly respected and globally influential psychologist like Adam. But it takes me by surprise how  superficial and loose his argument is – frankly, I find most of it invalid. Here’s how.

Adam’s first challenge: “The MBTI does poorly on reliability.”

Adam argues that the MBTI must produce as consistent results as physical tests of a broken leg. However, as he refers to a research study, “as many as three quarters of test takers achieve a different personality type when tested again” using the MBTI test.

The first question that comes to my mind as I read this is what the age range of the respondents participating in this study is. Are respondents in their 30s or 40s who tend to have already attained a good sense of who they are? Or are respondents university students who, more often than not, still struggle to understand themselves? The reason why I have that concern is because the level of self-awareness of test-takers has to be taken into account.

When we take a personality test, we are often requested to stay true to ourselves – give answers that are reflective of who we are, rather than who we want to be or think we should be. That reminder is basis the fact that we are prone to mistaking our ideal self for our actual self. Even if we embrace that instruction, sometimes, unluckily, we don’t know ourselves as well as we think we do. Recall when you last took a personality test, or when a friend asked you such questions as if you prefer going to an exciting party or enjoying the comfort of staying at home, or when you were in school, if you enjoyed subjects that are more factual or conceptual, how many times you answer, then pause, have a second thought, change your answer, and keep thinking again which one you actually like more. If a test taker gives different responses to the test questions due to their own self-confusion, how can the test produce consistent results? And in that case, where the fingers should point to, the test or the test taker?

The quality of the test outcome is as good as the quality of the responses a test-taker gives. When it comes to a personality test, be it the MBTI or any other personality test, reliability of the test depends on test-takers’ level of self-awareness. The more self-awareness someone has, the more reliable the test result for them is. Personally, I have taken the MBTI test 3 times, once when I was a university student, once when I just graduated from school, and once several years down the road into my career, the result is always the same type.

So hey, instead of criticizing the test for being unreliable, we’d better do a better job assessing ourselves. Solution for a reliable result: observe yourself, do self-reflection constantly, and do not take the test when you are undergoing any emotional turbulence.

Adam’s second challenge: the MBTI test doesn’t predict professional aptitude.

While he formulates his argument in a solid way, pointing out that a test “should shed light on how well I’ll perform in a particular job or with a certain group of people,” he backs it up with an example that weakens more than strengthens the argument.  Adam uses findings by management researchers William Gardner and Mark Martinko that, “Few consistent relationships between type and managerial effectiveness have been found.”

Now, first off, management is not a job. It’s the level of seniority and a skillset that anyone in a managerial position has to have, regardless of their job nature. So the merit of Adam’s argument is no more than what an argument like this deserves: “You know what, a personality test is supposed to tell whether a kid will perform better in math or art at school, but look, all the kids who go from grade 1 to grade 2 can READ. There’s no different among types at all. How useless this test is.”

Secondly, a person in a managerial position tends to be better-rounded than someone who is not. No matter whether you’re an ESFP who is not the most rational decision maker but works great with people, or you’re an INTJ who excels at strategy but regards interpersonal communication as your “Achilles’ heel”, you can’t make it to a managerial position if you don’t have a good balance of all these skills. Everyone has to improve. The only difference is in what each type has to improve. An ESFP manager has to improve herself or himself differently from an INTJ manager. But once they achieve a certain level of improvement, it’s no surprise that both perform on par, especially when their effectiveness is comprehensively evaluated across various skills, including both where their strengths and weaknesses are. To make this less abstract, think of student A and student B. Student A excels in math but struggles in literature. Let’s say student A gets 4/4 for math but 1/4 for literature. The other way around for student B. Now, if considering only math or literature, student A and B perform differently. But if assessed comprehensively, both students get 2.5/4 as their overall score of performance.

Only if Adam uses a finding that shows how across professions, all types perform similarly efficiently does his argument make any sense to me.

Adam’s third challenge: the MBTI combines traits that are independent and separate traits that are not.

I will quote his exact debate here:

In the MBTI, thinking and feeling are opposite poles of a continuum. In reality, they’re independent: we have three decades of evidence that if you like ideas and data, you can also like people and emotions. (In fact, more often than not, they go hand in hand: research shows that people with stronger thinking and reasoning skills are also better at recognizing, understanding, and managing emotions.) When I scored as a thinker one time and a feeler one time, it’s because I like both thinking and feeling. I should have separate scores for the two.

Now here are my two points to counter Adam’s argument:

(1) In the MBTI, thinking and feeling are, in fact, separate processes. The T/F component in the type indicates how much reliance a type has on either of these two independent processes when making decisions – whether the inner voices someone listens to comes from the head (logics) or the heart (emotions). Isabel Myers explicitly wrote about this in her book Gifts Differing, “Thinking and Feeling are rival instruments of decision.” Both the head and the heart voice their opinions. Just that one is trusted more than the other.

(2) The MBTI shows preference, not absolute proficiency, of exercising each of the two processes. When you’re young, you have 10 units of, let’s say, ‘judgment power’ (*), of which 6 units is thinking power and 4 units feeling. When you get older, your judgment power increases, let’s say, to 20 units. Then you have 12 units of thinking and 8 units of feeling. So yes, when you grow in thinking, you may grow in feeling too, because your overall judgement power has grown. But look, you still have more thinking power than feeling power. That’s what this indicator in the MBTI test indicates – your tendency, not static, absolute proficiency at any point in time.

A real life analogy to illustrate this can be right-handedness and left-handedness. A right-handed piano player can have highly agile left fingers thanks it her intensive practice. But no matter how much practice, their right fingers will still perform a bit better than the left ones. However, when compared with a person who doesn’t play the piano at all, of course, her left fingers are much stronger.

(*) thinking and feeling are called ‘judging processes’ in Jung’s theory and consequently, in the MBTI which is based on Jung’s theory

Adam’s forth challenge: the MBTI does not produce a comprehensive view of one’s personality.

Adam nicely calls the MBTI “a physical exam that ignores your torso and one of your arms” to demonstrate how comprehensive the personality test is to him. He points out that, “One of the key elements missing from the MBTI is what personality psychologists call emotional stability versus reactivity—the tendency to stay calm and collected under stress or pressure.”

Throughout Adam’s article, I find this the most (and the only) virtuous critique. As much as I agree that this is an “unfortunate oversight” of the MBTI (**), I believe this should be taken as an extension, a positive enhancement of the MBTI rather than a fatal oversight that disqualifies all of its merit.  Jung’s theory, which is the foundation of the MBTI, originally did not take into account the T/F dimension (so according to Jung, there are only 8 types) (Myers, 1995). Isable Myers and Katharine Briggs added this third dimension to make the theory more powerful.

The MBTI needs improvement. Even science needs correction. (By the way, I don’t know anything except for the Buddha’s teachings and the Bible that stay true over thousands of years). So there’s no surprise that the MBTI isn’t in a perfect shape yet. As an MBTI advocate, I look forward to meaningful enhancements that makes this powerful tool even more enabling for us to obtain more comprehensive and profound insights into human psychology.

(**) To factor in this important component that explains how some people tend to have more emotional stability than others, there is an added element: Turbulent or Assertive that can make the MBTI even more comprehensive as explained briefly in this article https://www.16personalities.com/articles/identity-assertive-vs-turbulent

Works Cited:

Myers, I. B. (1995). Gifts Differing. Palo Alto: Davies-Black Publishing.


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