The Evolution of Personality Testing
From ancient humors to data-driven psychometrics. Explore which tests are industry standards, which are obsolete, and how modern science measures who we are.
Historical Timeline
Personality assessment has shifted from physical observation (bumps on the head) to theoretical types, and finally to lexical statistical analysis. Click through the eras below.
Phrenology & The Humors
STATUS: DEBUNKED / OBSOLETEEarly attempts to measure personality were physical. Phrenology assumed that bumps on the skull corresponded to personality traits. Similarly, the "Four Humors" theory suggested bodily fluids controlled temperament.
Why is it no longer used?
Complete lack of scientific evidence. Neuroscience proved brain function is not readable via skull shape.
The Gold Standard: The Big Five (OCEAN)
Unlike "Type" indicators that put you in a box (e.g., Introvert OR Extrovert), the Big Five (and its update, HEXACO) measures personality on a spectrum. This model is the current industry standard due to its statistical reliability.
Use the sliders below to adjust the personality profile and see how the description changes.
Adjust Trait Levels
Imagination, curiosity, artistic interest.
Self-discipline, duty, achievement striving.
Sociability, assertiveness, emotional expression.
Cooperativeness, trust, altruism.
Emotional instability, anxiety, moodiness.
Visual Profile
Generated Analysis
Adjust the sliders to generate a personality analysis.
Note on HEXACO
Newer models like HEXACO add a 6th dimension: Honesty-Humility. While Big 5 is standard, HEXACO is gaining traction for predicting ethical behavior in the workplace.
Scientific Validity: The Hard Truth
Many "fun" tests (like MBTI or Enneagram) are incredibly popular in corporate settings but often lack scientific rigor. Psychometricians look for two things:
- Reliability If you take the test twice, do you get the same result? (MBTI often fails here, with up to 50% of people getting a different result after 5 weeks).
- Validity Does the test actually measure what it claims to measure? Does it predict real-world outcomes like job performance?
The "Barnum Effect"
Why are unscientific tests popular? They use vague, universally positive descriptions (like horoscopes) that everyone feels apply to them.
Predictive Validity for Job Performance
*Composite correlation coefficients based on meta-analyses (Schmidt & Hunter).
Accepted Applications
Where are these tests actually valid and useful today?
Recruitment & Hiring
💼Using validated traits (like Conscientiousness) to predict job performance and reliability.
Goal: Reduce turnover, predict fit.
Note: Must be job-relevant to avoid legal discrimination issues.
Click for details
Team Dynamics
🤝Understanding communication styles to reduce conflict and improve collaboration.
Goal: "Why does Bob annoy Alice?" - Building empathy.
Click for details
Clinical Psychology
🩺Diagnosing personality disorders and understanding psychopathology.
Goal: Identify narcissism, paranoia, depression, etc.
Strictly for professionals.
Click for details