Biological Foundations: Temperament and Personality

Biological Foundations

Chapter 9: Key Concepts and Terms

Terminology of Temperament and Personality

  • Temperament: Refers to the biologically-based behavioral style and characteristic emotional responses of an individual.

  • Personality: A product of social environment, shaped over time, comprising individual traits and behaviors.

  • Phrenology: A historical belief that specific mental faculties are located in particular regions of the brain, studied through the shape of the skull.

Key Aspects of Personality and Temperament

  • Biological Bases of Personality: Understanding of the personality influenced by biological science and case studies (example: Phineas Gage, who suffered frontal cortex damage and experienced changes in personality).

  • Connection between Brain Functioning and Personality: Gage's accident illustrated deep interconnections between changes in brain function and personality traits.

Phineas Gage Case Study

  • Incident Description: During railroad construction, a worksite explosion penetrated Gage’s skull with an iron rod, damaging his frontal cortex.

  • Aftermath: Survived but experienced significant personality changes, suggesting that areas of the brain are linked to personality characteristics.

Physiognomy

  • Definition: The practice of assessing personality traits based on facial features.

  • Examples:

    • Deceitful eye indicates a character prone to deceit.

    • Certain mouth shapes can suggest agreeableness mixed with selfish concerns.

Historical Perspective on Personality

  • Jerome Cardan's Metoposcopia: Described specific facial features correlated with personality traits (examples in illustrations include lines representing generosity, compassion, virtue, and other traits).

Phrenology and Franz Joseph Gall

  • Gall's Phrenology: Investigated the brain's physical attributes post-mortem, aiming to connect brain structure to personality traits.

  • Modern Contradictions: Contemporary neuroscience indicates more complex, interconnected brain functions, opposing the singular-attribution model of Gall.

Body Type Personality Theory

  • Types of Body Structures:

    • Endomorphy: Characterized by plumpness, associated with sociability and relaxation.

    • Mesomorphy: Muscularity linked with dominance and activity.

    • Ectomorphy: Thinness, associated with sensitivity and introversion.

Four Aspects of Temperament

  1. Activity Level: Amount of energetic output by an individual, often reflected in vigorous activities.

  2. Emotionality: Tendency to experience feelings like distress, anger, and fear intensely.

  3. Sociability: Preference for social interaction versus solitude, indicating a person's need for social engagement.

  4. Impulsivity/Aggressiveness: Immediate response to stimuli without regard for consequences, showing how an individual acts in various situations.

Thomas and Chess Study on Temperament Types

  • New York Longitudinal Study (NYLS): Followed children from infancy to adolescence, identified three primary temperament types:

    • Easy Babies: Adaptable, playful with fewer later-life adjustment issues.

    • Difficult Babies: Negative in response, leading to challenges as they grow.

    • Slow-to-Warm-Up Babies: Low reactivity but can adapt over time.

Dimensions of Infant Temperament

  • Key factors to observe in infant behavior:

    • Activity Level: Movement versus stillness.

    • Rhythmicity: Predictable patterns in biological rhythms such as sleep and feeding.

    • Approach-Withdrawal: Responses to new experiences or individuals.

    • Intensity of Reaction: Strength of responses to stimuli, ranging from extreme to mild.

    • Quality of Mood: Consistency in emotional demeanor (happy vs. irritable).

    • Distractibility: Susceptibility to being diverted from tasks or stimuli.

    • Attention Span: Capacity to focus on an activity over time.

Temperament and Biological Responses

  • Inhibition in Children: Distinguished between inhibited (restrained and fearful of novelty) versus uninhibited (energetically embracing new experiences).

  • Kagan's Research: Suggested genetic differentiation in children’s responses to social stimuli, evidenced by physiological markers like heart rates and norepinephrine levels in inhibited children.

Environmental Influence on Temperament

  • Kagan concluded that genetics influence temperament but parenting and environment play significant roles in shaping and modifying these characteristics. Responsive parenting can help children with difficult temperaments adapt and thrive.