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Is MBTI Scientific or a Scam? Evaluating Psychologists' Perspectives

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"I'm an INFP!" "ESTJs just don't work!" The MBTI craze is extraordinary. However, psychologists criticize MBTI as "pseudoscience, not science". It's a perfect example of the Barnum Effect. What's the truth?

First, read: What is the Barnum Effect?

What is MBTI?​

Basic Information​

Myers-Briggs Type Indicator

  • Developers: Katharine Cook Briggs, Isabel Briggs Myers (mother and daughter)
  • Development Period: 1940s
  • Theoretical Foundation: Carl Jung's Psychological Types

4 Dimensions

  1. E(xtraversion) vs I(ntroversion)
  2. S(ensing) vs N(intuition)
  3. T(hinking) vs F(eeling)
  4. J(udging) vs P(erceiving)

16 Types

  • 2×2×2×2 = 16 combinations
  • INFP, ESTJ, ENTP...

Popularity in Korea​

Statistics

  • Over 70% of Koreans know MBTI
  • Ask "MBTI" instead of "Blood Type"
  • Used in hiring, dating, friendships

Problems

  • Many treat it as science
  • Categorizing people into 16 types
  • "Should we break up if MBTI doesn't match?"

Psychological Community's Assessment: "Pseudoscience"​

1. Non-Professional Developers​

Shocking Facts

  • Katharine Briggs: Agricultural school teacher
  • Isabel Myers: Mystery novel writer
  • Neither had a psychology degree

Analogy

  • Health check created by someone without a medical license
  • Can it be trusted?

2. Low Reliability​

Different Results in Repeated Tests

Research Findings

  • 5 weeks later retest: 50% different type
  • 1 year later retest: 70% different type

Example

  • January: INFP
  • February: ENFP (I→E changed)
  • → Unreliable results

Analogy

  • Take a blood type test twice
  • A type → Changes to B type
  • Does that make sense?

3. Low Validity​

Cannot Predict Actual Behavior

Research

  • Predicting job performance: Failed
  • Predicting academic achievement: Failed
  • Predicting relationship satisfaction: Failed

Meaning

  • "INFP is creative" → Really?
  • "ESTJ is leadership-oriented" → Actually?
  • Almost no predictive power

4. Problem of Dichotomy​

E vs I, T vs F Are Continuous

MBTI's Claim

  • You are E(xtraverted) or I(ntroverted)
  • No middle ground

Reality

  • No one is 100% extraverted
  • No one is 100% introverted
  • Everyone is somewhere on the spectrum

Analogy

  • Tell someone 165cm tall
  • "You are either tall or short"
  • Nonsense!

5. Perfect Example of Barnum Effect​

INFP Description

"You are idealistic with a rich inner world.
Sometimes criticized for being impractical.
Creative, but also need alone time."

Problems

  • Applies to everyone
  • Ambiguous
  • Positive expression
  • → Typical Barnum Effect!

Scientific Personality Assessment: Big Five​

MBTI vs Big Five Comparison​

MBTI

  • Unscientific
  • Low reliability
  • 16 classifications
  • No predictive power
  • Commercial purpose

Big Five (5-Factor Model)

  • Scientific (thousands of papers)
  • High reliability
  • 5 continuous dimensions
  • Predictive power
  • Academic purpose

What is Big Five?​

5 Personality Traits (Continuous)

  1. Openness

    • Low: Prefer tradition, practical
    • High: Curious, creative

  2. Conscientiousness

    • Low: Spontaneous, flexible
    • High: Planned, responsible

  3. Extraversion

    • Low: Quiet, introspective
    • High: Sociable, active

  4. Agreeableness

    • Low: Competitive, critical
    • High: Cooperative, empathetic

  5. Neuroticism

    • Low: Stable, calm
    • High: Anxious, sensitive

Characteristics

  • 0-100 point spectrum
  • Midpoint values possible
  • Predict actual behavior
  • Consistent in repeated tests

Big Five's Predictive Power​

Research Results

Job Performance

  • High conscientiousness → Higher work performance
  • High neuroticism → More stress

Academic Achievement

  • High conscientiousness → Better grades
  • High openness → More creativity

Relationship Satisfaction

  • High agreeableness → Higher relationship satisfaction
  • High neuroticism → More conflicts

Big Five Actually Works!

1. Easy to Understand​

MBTI

  • "I'm an INFP" (simple)
  • 16 types (easy to memorize)

Big Five

  • "Openness 70, Conscientiousness 45..." (complex)
  • Expressed in numbers

Result: MBTI better for conversation

2. Positive Expressions​

MBTI

  • Positive description for all types
  • "You are special"
  • Pleasant to hear

Big Five

  • "You have high neuroticism" (negative feeling)
  • Objective description

3. Identity Provision​

Sense of Belonging

  • "I'm an INFP" (identity)
  • Join INFP community
  • Interact with similar people

Psychological Satisfaction

  • "Understand me!"
  • Framework for self-understanding

4. Commercial Marketing​

MBTI is Business

  • Test cost: tens of thousands of won
  • Corporate training: millions of won
  • Annual revenue: billions of dollars

Marketing Success

  • Certification system
  • Emphasize "official" test
  • Feeling of authority

How Should We View MBTI?​

1. OK for Fun​

Positive Use

  • Conversation topic with friends
  • "What's your MBTI?" Ice breaker
  • Starting point for self-reflection

2. NO as Science​

Problematic Uses

  • Demanding MBTI in hiring (discrimination)
  • "Won't date if MBTI doesn't match" (prejudice)
  • Using for life decisions (risky)

3. Absolutely NO as Judgment Tool​

Dangerous Cases

Hiring

  • "INFP lacks leadership" → Discrimination
  • Unrelated to actual abilities

Dating

  • "ESTJ and INFP don't match" → Prejudice
  • Relationships aren't determined by MBTI

Friendships

  • "You can't empathize because you're T" → Labeling

MBTI Fever in Korea: Problems​

1. Blind Faith in Science​

Problems

  • "MBTI is a scientific test" (False)
  • Official use in schools, companies
  • Uncritical acceptance

2. Putting People in Boxes​

Trap of 16 Classifications

  • Humans are complex
  • Cannot be classified into 16 types
  • Ignores individual diversity

3. Discrimination and Prejudice​

Real Cases

  • Job postings requiring MBTI
  • "Can't work with this type"
  • Discrimination without scientific basis

4. Self-Limitation​

"I can't be sociable because I'm I"

  • Blocking growth potential
  • Avoiding change
  • Self-restriction

Learn More​

Conclusion​

MBTI is an entertaining game, not science. It's a perfect example of the Barnum Effect.

Key Facts

  1. Developed by Non-Professionals - No psychology degree
  2. Low Reliability - 50% different result on retest
  3. Low Validity - Cannot predict behavior
  4. Dichotomy Error - Forcing continuous spectrum into binary
  5. Barnum Effect - Descriptions apply to everyone

Psychological Community Consensus

  • "Pseudoscience"
  • "Commercial tool"
  • "No academic value"

Scientific Alternative

  • Big Five Personality Test
  • Verified reliability and validity
  • Can predict actual behavior

Healthy Usage

  • ✅ Enjoy for fun
  • ✅ Conversation topic
  • ✅ Starting point for self-reflection
  • ❌ Believe as science
  • ❌ Tool for judging people
  • ❌ Use for important decisions

Remember

  • MBTI does not define you
  • You are not one of 16 types
  • You are a unique individual

Don't limit yourself by saying "I can't because I'm I". MBTI cannot define your possibilities.

Enjoy it for fun, but don't blindly believe! 🎭