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4.2

Oct 5, 2025

Overview

This lecture covers Hans Eysenck's contributions to the biological and trait approaches in personality psychology, and introduces the concept of universal traits through natural selection.

Hans Eysenck and Supertraits

  • Hans Eysenck pioneered the biological approach to personality, building on trait theory.
  • He predicted three "supertraits" with high genetic influence: extraversion, neuroticism, and psychoticism.
  • Extraversion and neuroticism align with current Big Five traits; psychoticism reflects abnormal traits not measured in standard personality tests.
  • Eysenck developed a trait hierarchy, placing supertraits at the top, followed by narrower traits and specific habitual/behavioral responses.
  • Example: Extraversion includes traits like sociability, linked to habitual responses (e.g., liking crowds) and specific behaviors (e.g., attending parties).

Biological and Physiological Approaches

  • Eysenck emphasized physiological bases for personality, such as sensitivity to stimulation.
  • He found differences in caffeine sensitivity: introverts are more affected than extroverts due to physiological differences.

Natural Selection and Universal Traits

  • The concept of natural selection explains how traits with reproductive advantages become more common in populations.
  • Universal traits are traits/preference patterns widespread within a species or a gender due to evolutionary success.
  • Example given: Preference for partners of fertile age becomes universal among men over generations due to reproductive advantage.
  • Universal traits may differ between genders due to different reproductive challenges and environments.

Key Terms & Definitions

  • Supertrait — A broad personality dimension with high genetic influence, such as extraversion or neuroticism.
  • Trait Hierarchy — Eysenck's model: supertraits at the top, then narrower traits, habitual responses, and specific behaviors.
  • Psychoticism — A trait involving coldness and lack of empathy, considered abnormal.
  • Universal Trait — A characteristic or preference widespread within a population or a gender due to evolutionary success.
  • Natural Selection — The process where traits that improve reproductive success become more prevalent in a population.

Action Items / Next Steps

  • Review the differences between normal and abnormal traits in personality models.
  • Prepare for the next lecture segment on David Buss and evolutionary approaches to personality.