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Posts tagged with MBTI

Isabel Briggs’ first 5 college boyfriends were impermanent enough to warrant only a letter in her diary. B was “the British type”; F “the religious type”; H “the temperamental type”; J was nondescript, a bore; C was “the type of” man whom you liked, but he liked you more.

None of them mattered except as the wrong type of man for her.

Isabel’s mother, Katharine, wanted her to marry a man with “strength” and “control”, as well as an uncompromising “moral code”—not to judge a potential husband “by their clothes or their dancing or their particular ‘line’ of conversation”. But that ended up being exactly how Isabelle chose Clarence Gates Myers.

Isabel wanted someone bigger and stronger than her, someone who wouldn’t seem “a nice little boy all the time”.

…How could one reconcile real people to either mother’s or daughter’s generic descriptions of human beings?

But Chief [Clarence Gates Myers] was singular, “real”, worthy of a full name. He was an Iowa farm boy who had never heard of Swarthmore before being offered a scholarship to attend college there.

Isabel thanked G-d first for his height—all six feet, four inches of it—then for his dancing abilities, and finally for his “realness”. They met at an otherwise tiresome college mixer—a freshman-junior dance. Through their first hours together they debated many things, including whether women were inherently fickle, governed by their feelings. “I can talk to him about real things, no kidding”, Isabel wrote in her diary.

Merve Emre, The Personality Brokers

mangled by me

(Source: merveemre.com)




People make a big deal over how humans are too complicated to ever be described by mathematics. (I don’t agree.  Topic for another time.) So it’s astonishing that so many people give credence to the Myers-Briggs Type Indicator test.

Simplistic

The MBTI classifies people into sixteen categories, based on their proclivity to:

  1. Extraversion
  2. Facts vs. Ideas
  3. Heart vs. Head
  4. Like things settled vs. Like things open-ended

Each dimension varies on a sliding scale, so one’s score on a 100-question test is like [0,1] × [0,1] × [0,1] × [0,1] (actually it’s sparser in practice and could be several dimensions smaller, due to overlap).

![MBTI < [0,1]^4 … how bad is it?](http://latex.codecogs.com/gif.latex?\dpi{300} \bg_white \begin{matrix} \rm{MBTI}%20%3C[0,1]^4 \ \ \widehat{\rm{MBTI}} \overset{?} \cong {0,1}^4 \end{matrix})

Now that’s a shocker!  I know that we’re supposed to stick to simple models to describe things, but four parameters is the same as a bloody electron!  How are these four static numbers supposed to capture such a large chunk of human complexity?

Measures the Wrong Stuff, and Measures Unreliably

The model discards many characteristics that could be relevant–nice, creative, clever, honest, hard-working, religious, favorite sandwich–that’s a hack list but the point is, I don’t think they’re measuring the principal components of personality.

Not only that – but the test isn’t even sound.  One, MBTI asks people to describe themselves, with no external check.  Two, the best validation of it is a 90% consistency only if testing the same people soon after.  Let’s turn that around and say that in 10% of cases the test fails a basic scoff test.  Three, Wikipedia claims (with citation) that merely 36% of adults remain the same type after more than nine months.

I’m being harsh, but there really are some people who take the MBTI too far – using it to plan corporate teams, screening job candidates because they “don’t fit” according to a far-out extrapolation of the theory.

I remember in my first sales job the trainer used a stripped-down version of MBTI (4 types) to help us characterize customers quickly.  It was fine for that task–but shouldn’t be used for serious stuff like career counseling.  I’m thinking of books like Do What You Are – as if who you are doesn’t change over time, or wouldn’t be influenced by the job market!  Jeesh.

History

So where does the MBTI come from, anyway?  The first three parameters come from schlockmeister Jung, the same one who gave us “cultural memory” and the book Synchronicity.  Well my trust in those is blown.  [Persi Diaconis, the statistician’s statistician (and magician), refuted the improbable nature of the coincidences that comprise _Synchronicity_.] 

Read the Wikipedia article for more of this history.  But essentially the practical purpose that brought MBTI typology into common use was its application in the US during WW II, to match women to jobs while the men were at war.  It wasn’t intended to find them a fulfilling career for life – merely to point people who had worked exclusively at home toward a factory or office that they were more likely to enjoy.

Now that is an appropriate sized job for the MBTI.  It shouldn’t be used for important stuff like screening employees, managing them, choosing a career, or making definitive judgments about anyone.  The typology is too small, people change, the test is unreliable, and these four factors probably aren’t the principal components.

Added, 2015: I just realised that the MBTI also phrases things in terms of {±,±,±,±}. But does it make more sense to assume that the distribution of personalities is polarised on each dimension? Or should we assume that more people are neither “very extraverted” nor “very intraverted”, but rather “not strongly one or the other”? Maybe the composite-average individual is halfway between on all dimensions.