Eysencks' Personality Theory: Dimensions and Quadrants

Introversion/Extraversion Dimension:
- High on Extraversion: Individuals tend to have a strong need to connect with others and engage in social behaviors.
- High on Introversion: Individuals exhibit a higher need to be alone, prefer solitary activities, and limit their interactions with others.
Neuroticism/Stability Dimension:
- High on Neuroticism:
  - Characterized by proneness to anxiety.
  - Possess an overactive sympathetic nervous system.
  - Even under low-stress conditions, their bodies and emotional state are prone to entering a flight-or-fight reaction.
  - Considered emotionally unstable.
- High on Stability:
  - Require more significant stimulation to activate their flight-or-fight reaction.
  - Considered more emotionally stable.

Based on the combination of these two dimensions (introversion/extraversion and neuroticism/stability), Eysencks' theory categorizes people into four distinct quadrants.
These quadrants are often compared to the four temperaments conceptualized by the ancient Greeks:
- Melancholic
- Choleric
- Phlegmatic
- Sanguine