Chapter 7: Exercises

Comprehension Check

1. List three specific psychometric problems with the Myers-Briggs Type Indicator. For each, explain why it undermines the validity of the assessment.

2. Who created the MBTI, and what was their academic background? Why does this matter?

3. What personality dimension does the MBTI fail to measure that the Big Five includes? Why is this omission significant?

4. What is the difference between a personality "type" (as the MBTI uses) and a personality "dimension" (as the Big Five uses)? Why does this structural difference matter for measurement?

5. Why is the Big Five the consensus model among personality researchers? List three features that distinguish it from the MBTI and Enneagram.

Application

6. If you have an MBTI type, take a free Big Five inventory (e.g., IPIP-NEO). Compare: - Your MBTI type description vs. your Big Five profile - Which feels more personally accurate? Which is more scientifically valid? - Does the Big Five profile capture anything your MBTI type misses?

7. Find the MBTI type descriptions for your type and for the "opposite" type (e.g., if you're INTJ, read the ESFP description). How many statements in EACH description feel at least partially true of you? This tests for the Barnum effect.

8. Ask three people who know you well to describe your personality in their own words (without using MBTI or Enneagram labels). Compare their descriptions to your MBTI type. How well do they match?

9. Research what your company or school uses for personality assessment. If they use MBTI or Enneagram: - What is it used for? (team building, hiring, development?) - Is the use appropriate given the evidence? - What would a more evidence-based alternative look like?

10. Find three Enneagram content creators on social media. Evaluate their posts using the toolkit: - Do they cite empirical research? - Are their claims testable? - How would you distinguish their approach from astrology?

Critical Thinking

11. The MBTI is psychometrically unsound but is used by 88% of Fortune 500 companies. What does this tell us about the relationship between corporate adoption and scientific validity? Is corporate use evidence of effectiveness?

12. If the MBTI is functioning as entertainment and community (like a Hogwarts house), is it harmless? Or does the "scientific" framing make it more harmful than explicitly fictional personality frameworks?

13. The Big Five is scientifically superior but culturally unpopular because it lacks narrative, includes unflattering dimensions, and doesn't create community. Could the Big Five be redesigned for popular appeal without sacrificing scientific validity? What would that look like?

14. Jung warned against using his types as a classification system. The MBTI did exactly that. Is this a case of the mutation pipeline (Chapter 2) operating on a theoretical framework rather than a research finding?

15. Some MBTI defenders argue: "It's not about the science — it's about starting conversations about personality differences." Is "conversation starter" a sufficient justification for a tool with no validity? Where is the line between useful icebreaker and misleading assessment?

Fact-Check Portfolio

16. If any of your 10 claims involve personality types or assessments, apply this chapter's findings: - Does the assessment cited have psychometric evidence? - Does it use types or dimensions? - Does it predict real-world outcomes? - Who profits from its continued use? Update your preliminary evidence ratings.