MBTIと職業で気になったこと

この記事の発端とMBTIは誤っていること

MBTIに関してたまにネットで検索をしていると、MBTIと職業を結びつけている投稿を結構見かける。以下にいくつか例を挙げる。

mbti.jp

sw8pc5.hatenablog.com

yourcalling.blog.fc2.com

note.mu

osakanafly.info

hiah.minibird.jp

hiah.minibird.jp

多くはネタとしてMBTIを消費しているだけであると思われるが、中にはかなり真面目に考えている人もいて、その場合には個人的にとても驚いてしまう。

というのも、MBTIというのは現代の心理学では信頼性はないとされているからだ。

APA Dictionary of Psychology

Myers–Briggs Type Indicator (MBTI)

(略)The test has little credibility among research psychologists but is widely used in educational counseling and human resource management to help improve work and personal relationships, increase productivity, and identify interpersonal communication preferences and skills.

そもそもMBTIやエニアグラムなどといった類型論自体、根本的に誤っているという指摘もある。

Spent: Sex, Evolution, and Consumer Behavior

This simple fact has profound implications for marketing, as it means that most distinct personality types used in market segmentation are illusory. The outdated Myers-Briggs dichotomies (feeling versus thinking; judging versus perceiving) just can’t work if the underlying traits are normally distributed.

As we have seen, in the space of human personality traits, we really have what statisticians call a multivariate normal distribution: each dimension is a bell curve with most people near the average, and each dimension is independent of the others. Given our six independent dimensions, if we split each into just three levels (low, average, or high), then we’d have three to the sixth power possible combinations, or 729 different personality types—rather larger than the number of types typically posited in astrology, Jungian psychoanalysis, or most market segmentation.

パーソナリティ心理学―全体としての人間の理解

類型では男性あるいは女性といった離散的カテゴリーを想定するのに対し、多くの特性は「友好性」のように連続した次元上で測定される。(略)例えば、内向-外向の類型においては、内向-外向という性質を示す程度は個人によって異なる。しかし、純粋にどちらかの特徴しか持たない人はいない。このために、ほとんどの性質あるいは特性については個人差の心理学的な連続体を想定するほうが望ましい。

Unweaving the Rainbow: Science, Delusion and the Appetite for Wonder

Personality is a real phenomenon and psychologists have had some success in developing mathematical models to handle its variation in many dimensions. The initially large number of dimensions can be mathematically collapsed into fewer dimensions with measurable, and for some purposes conscionable, loss in predictive power. These fewer derived dimensions sometimes correspond to the dimensions that we intuitively think we recognize—aggressiveness, obstinacy, affectionateness and so on. Summarizing an individual's personality as a point in multidimensional space is a serviceable approximation whose limitations can be stated. It is a far cry from any mutually exclusive categorization, and certainly far from the preposterous fiction of newspaper astrology's 12 dumpbins. It is based upon genuinely relevant data about people themselves, not their birthdays. 

The psychologist's multidimensional scaling can be useful in deciding whether a person is suited to a particular career, or a proposed couple to each other. The astrologer's 12 pigeonholes are, if nothing worse, a costly and irrelevant distraction.

 また、MBTIと職業との関係についても残念な感じである。

臨床心理学における科学と疑似科学

数ダースのMBTIの妥当性研究を科学的文献で入手できる。それらの研究はMBTI指向スコアとタイプを、多種多様のパーソナリティ構成概念、能力測度、職業に関係づけようとしている。それにもかかわらず、検査結果から妥当な解釈を導くために、研究からのデータを統合しようという現実的な試みはなかった。さらに、MBTIの予測妥当性(たとえば、MBTIに基づいて教育とキャリア選択の確かな予測が可能かどうか)や、増分妥当性と実用性(これらの決定の予測にMBTIが有意義な情報を加えるか、MBTIデータに基づいた教育やキャリア、雇用決定は最適であるか)についての情報は少ない。

全体的なパーソナリティの測度として、MBTIは、よく確立された他の職業測度やパーソナリティ測度と関連が認められないと批判されてきた。検査手引きに一連の併存的妥当性データが含まれていることに対する検査開発者の努力は、賞賛に値するものであるが、４つのパーソナリティ指向が、他の測度によって査定された類似の構成概念と関係することを示す一貫した事実に乏しい。発表された研究によれば，MBTIは職業指向と職業業績の測度とほとんど対応しない（たとえばApostal & Marks, 1990; Furnham & Stringfield, 1993）。加えて、全体的なパーソナリティの測度として、MBTIは、最も一般的な人格構造の２つの科学的モデルであるアイゼンクの３因子モデルと５因子モデルのどちらにもあまり一致しない（Furnham, 1996; McCrae & Costa, 1989; Saggino & Kline, 1996; Zumbo & Taylor, 1993; しかしMacDonald et al., 1994を参照）。このようにMBTIは，現代のパーソナリティ測度として不十分と結論できる。

fortune.com

Would a change to one of these careers make me more fulfilled? Unlikely, according to psychologist David Pittenger, because there is “no evidence to show a positive relation between MBTI type and success within an occupation … nor is there any data to suggest that specific types are more satisfied within specific occupations than are other types.” Pittenger advises “extreme caution in [the MBTI test’s] application as a counselling tool.”

www.bbc.com

In a statement provided to the BBC, CPP*1 president Jeffrey Hayes defends the test's validity.

"It's the world's most popular personality assessment largely because people find it useful and empowering, and much criticism of it stems from misunderstanding regarding its purpose and design," he says. "It is not, and was never intended to be predictive, and should never be used for hiring, screening or to dictate life decisions."

MBTIを信じている人

MBTIは非科学的であることというのは、上記の本を調べるまでもなく、英語版のWikipedia*2辺りにはすでに書かれていることである。しかし、ここにある文章を読んですぐにMBTIを捨て去ることはなかなか考えにくい。英語圏で生まれて英語を難なく利用できる人で、Wikipediaの非科学的な記述を読んでもMBTIに固執している人はいくらでもいるからだ。

科学的な態度を保つのであれば、科学の歴史上で現象を説明するため作られ後になって廃棄された概念――例えばエーテル、熱素、フロジストンなど――に沿って、MBTIやその他類型論は棄却されるはずである。そして棄却された穴埋めは、現代の科学で整合性が高い暫定的な概念、例えばビッグファイブといったもので埋め合わせがされる。それにもかかわらずそういったものが固執されるとしたら、いくつかの場合が考えられる。

娯楽や消費としてのMBTI

いまさら言うまでもないが、血液型占いは科学的にも正しくないし、多くの人は単なる嘘話と思っている。ただ遊んでいるだけだ。MBTIで言えば、フィクションのキャラクターにMBTIを適応させるといったことが挙げられるだろう。それらしい体裁は整えられているが、みんな一連のことが嘘話でナンセンスあることがわかっている*3。このことは、サンタクロースやシャーロキアンと似たようなことである。

Breaking the Spell: Religion as a Natural Phenomenon

Some people may be under the mistaken impression that Sherlock Holmes actually existed and that Conan Doyle's stories aren't fiction. These people believe in Sherlock Holmes in the strong sense (let us say). Others, known as "Sherlockians," devote their spare time to becoming Sherlock Holmes scholars, and can entertain one another with their encyclopedic knowledge of the Conan Doyle canon, without ever making the mistake of confusing fact with fiction. The most famous society of these scholars is the Baker Street Irregulars, named after the gang of street urchins that Holmes enlisted for various purposes over the years. Members of these societies (for there are many "Sherlockian" societies around the world) delight in knowing which train Holmes took from Paddington on May 12, but know full well that there simply is no fact to be learned about whether he faced forward or backward in the train, since Conan Doyle didn't specify it or anything that would imply it. They know that Holmes is a fictional character, but nevertheless they devote large parts of their lives to studying him, and are eager to explain why their love of Holmes is better justified than some other fan's love of Perry Mason or Batman. They believe in Sherlock Holmes in the weak sense (let us say). They behave very much like the amateur scholars who devote their spare time to trying to figure out who Jack the Ripper was, and an observer who didn't know that the Holmes stories are fiction whereas Jack the Ripper was a real murderer might naturally suppose that the Baker Street Irregulars were investigating a historical person.

強い意味でMBTIを信じている人たち

一方で、強い意味でMBTIを信じている人たちもいる。非科学的なことがわかっていても真剣にMBTIを扱い続ける人だ。おそらく、そういった人は｢INFPは天才でクズで生きづらくて性格が悪い。加えてADHDで精神病だ｣*4といった発言に対して、まるで自分が攻撃をされたかのように、激烈に反応するのではないかと思える。さらに｢熱くなるなよ。たかが性格診断でしょ*5｣とでも言えば、きっと余計に怒るのだろう。

強い意味でMBTIを信じるには、ビッグファイブで言うところの高い開放性と低い一般知能が必要であると思われる。更にネットで見られる多くの人は、低い外向性、高い神経質傾向、高い同調性も加わると考えられる。あえてMBTIで言えばINFP-Tのことだ*6。

Spent: Sex, Evolution, and Consumer Behavior

 The only major exception is that general intelligence has a modest positive correlation with openness: bright people tend to be more interested than average in new experiences, travel, culture, and aesthetics. Conversely, people who are culturally engaged and open-minded tend to be brighter than average. For this reason, university towns tend to have better cultural institutions. Yet even here the small size of the positive correlation means that there are plenty of bright but conventional people, who may work as engineers for the military-industrial complex, listen to the same classic rock they did thirty years ago, and know forty gigabytes of baseball statistics. Likewise, there are plenty of open-minded novelty seekers who love strange ideas and experiences, but who are not very bright. They constitute the market for fantasy novels, self-help books, nutraceuticals, facial piercings, music by Enya, degrees in nonevolutionary psychology, and every product labeled “homeopathic.” Indeed, their combination of neophilia and inanity make them an extremely profitable market segment.

もしもあなたがここまで英語の文章を飛ばさず、その内容を理解していたら、地球空洞説やフロイト昇華説*7と同じようにMBTIや類型論をゴミ箱に突っ込むことが出来る。しかし、あなたがMBTIやその他類型論を経由したコミュニティに随分と入れ込んでいたら、コミュニティでの新たな振る舞い方を考える必要が出てくるだろう。

Enlightenment Now: The Case for Reason, Science, Humanism, and Progress

The 21st century, an age of unprecedented access to knowledge, has also seen maelstroms of irrationality, including the denial of evolution, vaccine safety, and anthropogenic climate change, and the promulgation of conspiracy theories, from 9/11 to the size of Donald Trump’s popular vote. Fans of rationality are desperate to understand the paradox, but in a bit of irrationality of their own, they seldom look at data that might explain it.

The standard explanation of the madness of crowds is ignorance: a mediocre education system has left the populace scientifically illiterate, at the mercy of their cognitive biases, and thus defenseless against airhead celebrities, cable-news gladiators, and other corruptions from popular culture. The standard solution is better schooling and more outreach to the public by scientists on television, social media, and popular Web sites. As an outreaching scientist I’ve always found this theory appealing, but I’ve come to realize it’s wrong, or at best a small part of the problem.

In a revolutionary analysis of reason in the public sphere, the legal scholar Dan Kahan has argued that certain beliefs become symbols of cultural allegiance. People affirm or deny these beliefs to express not what they know but who they are.We all identify with particular tribes or subcultures, each of which embraces a creed on what makes for a good life and how society should run its affairs. These creeds tend to vary along two dimensions. One contrasts a right-wing comfort with natural hierarchy with a left-wing preference for forced egalitarianism (measured by agreement with statements like “We need to dramatically reduce inequalities between the rich and the poor, whites and people of color, and men and women”). The other is a libertarian affinity to individualism versus a communitarian or authoritarian affinity to solidarity (measured by agreement with statements like “Government should put limits on the choices individuals can make so they don’t get in the way of what’s good for society”). A given belief, depending on how it is framed and who endorses it, can become a touchstone, password, motto, shibboleth, sacred value, or oath of allegiance to one of these tribes.

Kahan notes that people’s tendency to treat their beliefs as oaths of allegiance rather than disinterested appraisals is, in one sense, rational. With the exception of a tiny number of movers, shakers, and deciders, a person’s opinions on climate change or evolution are astronomically unlikely to make a difference to the world at large. But they make an enormous difference to the respect the person commands in his or her social circle. To express the wrong opinion on a politicized issue can make one an oddball at best—someone who “doesn’t get it”—and a traitor at worst. The pressure to conform becomes all the greater as people live and work with others who are like them and as academic, business, or religious cliques brand themselves with left-wing or right-wing causes. For pundits and politicians with a reputation for championing their faction, coming out on the wrong side of an issue would be career suicide.

What’s going on is that these people are sharing blue lies. A white lie is told for the benefit of the hearer; a blue lie is told for the benefit of an in-group (originally, fellow police officers). While some of the conspiracy theorists may be genuinely misinformed, most express these beliefs for the purpose of performance rather than truth: they are trying to antagonize liberals and display solidarity with their blood brothers. The anthropologist John Tooby adds that preposterous beliefs are more effective signals of coalitional loyalty than reasonable ones.Anyone can say that rocks fall down rather than up, but only a person who is truly committed to the brethren has a reason to say that God is three persons but also one person, or that the Democratic Party ran a child sex ring out of a Washington pizzeria.

結論

世の中には｢MBTIは人生で役に立ち、有効なものだ｣と本気で信じている人がいる。下手すれば、救われたと感じる人もいる。MBTIという性格診断自体、加えて適職という印象論を展開する場合には、真面目に信じ込む人を出さない為にも｢MBTIというのは、熱素と同じように終わった概念で、実務上も人間や職業を測れていないのだから、診断結果は血液型占いと同じ様なものです｣と予め示しておいたり、共通理解としていた方がいいのではないだろうか。

Breaking the Spell: Religion as a Natural Phenomenon

Science is like a blabbermouth who ruins a movie by telling you how it ends. —Ned Flanders (fictional character on The Simpsons)

You're at a concert, awestruck and breathless, listening to your favorite musicians on their farewell tour, and the sweet music is lifting you, carrying you away to another place . . . and then somebody's cell phone starts ringing! Breaking the spell. Hateful, vile, inexcusable. This inconsiderate jerk has ruined the concert for you, stolen a precious moment that can never be recovered. How evil it is to break somebody's spell! I don't want to be that person with the cell phone, and I am well aware that I will seem to many people to be courting just that fate by embarking on this book.

Unweaving the Rainbow: Science, Delusion and the Appetite for Wonder

Why, in Keats's 'Lamia', is the philosophy of rule and line 'cold', and why do all charms flee before it? What is so threatening about reason? Mysteries do not lose their poetry when solved. Quite the contrary; thesolution often turns out more beautiful than the puzzle and, in any case, when you have solved one mystery you uncover others, perhaps to inspire greater poetry. The distinguished theoretical physicist Richard Feynman was charged by a friend that a scientist misses the beauty of a flower by studying it. Feynman responded:

The beauty that is there for you is also available for me, too. But I see a deeper beauty that isn't so readily available to others. I can see the complicated interactions of the flower. The color of the flower is red Does the fact that the plant has color mean that it evolved to attract insects? This adds a further question. Can insects see color? Do they have an aesthetic sense? And so on. I don't see how studying a flower ever detracts from its beauty. It only adds.
from 'Remembering Richard Feynman', The Skeptical Inquirer (1988)

 

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*1:CPPはMBTI試験の権利を所有する会社

*2:Myers–Briggs Type Indicator - Wikipedia

*3:ですよね? 少なくともこのブログを書いている人間はそうです

*4:これは今日GoogleでINFPと検索した時に、関連キーワードで出てくる形容詞的意味をもつ言葉をただ並べたものである。

*5:加えて血液型占いと同じで錯覚に過ぎない

*6:かつてINFP型専用のSNSがあったが、そのSNSではINFP型だけで数百人の参加者がいた

*7:Freudian defense mechanisms and empirical findings in modern social psychology: Reaction formation, projection, displacement, undoing, isolation, sublimation, and denial.