PSY405 Notes Lecture 28

FACTOR ANALYTIC TRAIT THEORY

(Raymond Cattell)

Raymond Cattell wanted to answer one simple question: “What exactly is personality, and how can we measure it scientifically?” Instead of guessing or using philosophy, he used statistics (numbers) and a method called factor analysis to discover personality traits. 👉 His idea: Personality is made of traits Traits can be discovered from behavior We should use data + mathematics, not opinions

1️⃣ FACTOR ANALYSIS (Foundation of the Theory)

🔹 What is Factor Analysis? (Plain English)

Factor analysis is a statistical method that: Takes many behaviors Finds patterns Groups them into hidden factors 👉 These hidden factors = traits

🔹 Correlation (Key Term)

Correlation = when two things change together 📌 Example: Tall people often weigh more → positive correlation More stress, less sleep → negative correlation 📊 Correlation coefficient: +1 = perfect positive –1 = perfect negative 0 = no relationship

🔹 How Cattell Used Factor Analysis (Step by Step)

1. Measure many people

Behavior Questionnaires Tests

2. Correlate everything

Compare every score with every other score Creates a correlation matrix (big table of numbers)

3. Find clusters

Behaviors that “go together”

4. Name the factor

This factor = trait

📌 Cattell believed traits are the building blocks of personality

🔹 Types of Data Cattell Used

Type Meaning

L-data

Life record Real-life behavior

Q-data

Questionnaire Self-reports Type Meaning

T-data

Test data Objective tests 📌 Example: L-data → attendance record Q-data → “I am shy” T-data → reaction time test

2️⃣ BIOGRAPHICAL SKETCH (Why It Matters)

Cattell: Born 1905 in England Witnessed World War I injuries as a child Became interested in human behavior and suffering Worked in: University of London Clark University Harvard University of Illinois 👉 His life experience pushed him toward:

Scientific psychology · Measurement · Genetics + environment · 3️⃣ THE NATURE OF PERSONALITY