Notes on Psychology: Human Behaviour - General & Specific Intelligence

Components of ‘g’

• Intelligence can be understood through the concept of ‘g’, a general cognitive ability.
• Most cognitive abilities are correlated, suggesting a positive manifold, although this correlation is not perfect.
• Spearman’s Two-Factor Theory:
  • ‘g’: shared factor of all mental abilities
  • ‘s’: specific factors reflecting individual abilities that contribute to overall intelligence.

Layers Leading to ‘g’

• Intelligence tests yield different scores, illustrating that ‘g’ acts as a statistical nexus where specific scores trend together.

Underlying Reality of ‘g’

• ‘g’ is considered a latent variable linked to distinct ability tests, leading to questions about its literal definition. Possible contributors include:
  • Neurodevelopmental factors
  • Speed and accuracy of neural transmission
  • Global practice effects from challenges
  • Task focus
  • Test familiarity

Contextual Contributors to ‘g’

• Real-world factors play a role in completing ability tests, affecting ‘g’.

Reductive Model of ‘g’

• Examines how performance regularities in tests arise from differences in intellectual abilities.

Familiarity Model of ‘g’

• Test familiarity significantly influences performance; IQ scores can be lower with unfamiliar testing modalities, often correlated with schooling.

Motivational Model of ‘g’

• Motivation is crucial for performance in IQ tests:
  • Undermined motivation leads to lower scores.
  • Financial incentives increase motivation and contribute to IQ score enhancements.

Underlying Merits of ‘g’

• Understanding and measuring specific domains of intelligence are debated. There are several useful distinctions in mental abilities, but compatibility varies across definitions and approaches.

Modelling Item Responses

• Bifactor models provide a different perspective than Spearman’s model by suggesting specific intelligence factors make independent statistical contributions to test performance.

Models of Specific Intelligence

• The textbook outlines key models for subdividing intellectual abilities:
  • Wechsler Scales: Distinguished between verbal and non-verbal intelligence.
  • Cattell-Horn GfGc Model: Differentiates fluid (problem-solving) vs. crystallized (accumulated knowledge) intelligence.
  • Carrol’s Three Stratum Model: A hierarchical model that includes broad and specific factors of intelligence.

Fluid & Crystallized Intelligence

• Fluid Intelligence: Ability to learn and solve new problems.
• Crystallized Intelligence: Accumulated knowledge and skills over time.

Carrol's Three Stratum Model

• Stratum III: General Intelligence.
• Stratum II: Broad categories that include fluid and crystallized intelligence alongside other abilities.
• Stratum I: Specific skills and cognitive processing capabilities e.g., reasoning, language development, memory.

Textbook Issues

• Certain theories about intelligence lack robust empirical support but still appear in texts:
  • Gardner’s Multiple Intelligences: Proposes various intelligences—linguistic, logical, musical, etc.
  • Sternberg’s Triarchic Theory: Emphasizes analytical, creative, and practical intelligence.

Questionable Characterisations

• Both Gardner’s and Sternberg’s theories have valuable insights but diverge from the ‘g’ concept, despite correlations between their distinct domains.

Conclusion

• A strong general intelligence factor ('g') exists, supported by empirical data.
• Distinct abilities relate to ‘g’, but many multiple intelligence models do not hold up well against empirical scrutiny.