Psychology 2e - Measures of Intelligence

Learning Objectives

• Explain development of intelligence tests
• Describe the history of IQ test usage
• Understand purposes and benefits of intelligence testing

Understanding IQ

• IQ (Intelligence Quotient): A score from tests designed to measure intelligence
• Debate over definition: Multiple intelligences vs. single measure

Uses and Controversies

• Applications: Education, psychological evaluation
• Limitations: Historical misuse (e.g., eugenics)
• Controversial cases: e.g., Buck v. Bell legalized forced sterilization

Development of IQ Tests

• Early Testing:
  • Sir Francis Galton (1800s) initiated broad intelligence tests
  • Alfred Binet (early 1900s) developed tests for French children, focusing on verbal tasks
  • Louis Terman standardized Binet's test (Stanford-Binet Intelligence Scale)

Wechsler's Contributions

• Wechsler-Bellevue Intelligence Scale (1939):
  • Combined verbal and nonverbal skills
  • Evolved into the Wechsler Adult Intelligence Scale (WAIS)
  • Other tests: WISC-V, WPPSI-IV
  • Focus on multiple cognitive abilities

Modern Testing and the Flynn Effect

• Recalibration: Regular updates to maintain test relevance
• Flynn Effect: Observation of rising IQ scores over generations

Validity of Intelligence Tests

• Concerns:
  • Debate on skills assessed
  • Limitations in measuring true intelligence

Key Case Studies

Atkins v. Virginia

• Background: Daryl Atkins' intellectual disability questioned in a death penalty case
• Outcome: Supreme Court rules against execution of intellectually disabled individuals
• Impact: States to define intellectual disability standards

The Bell Curve

• IQ Distribution:
  • Normal bell curve distribution
  • Standard deviations show variance
  • Average IQ is 100, SD is 15
  • IQ < 70 can indicate intellectual disability

Intellectual Disabilities

• Subtypes: Mild, Moderate, Severe, Profound
• DSM-5 Criteria: Details cognitive deficits and adaptive functioning

High Intelligence

• Gifted Individuals: IQ > 130
• Study by Lewis Terman: High IQ individuals well-adjusted and successful
• Mensa: Organization for top 2% IQ scores

Terminology and Social Impacts

• Shift from "Mental Retardation" to "Intellectual Disability"
  • Rosa's Law supports this change
  • Reflects societal language evolution

Importance of Measuring Intelligence

• Educational and Clinical Benefits:
  • Identifying learning difficulties
  • Legal implications for defendants
  • Social security benefits

Case Study: Candace

• Background: 14-year-old with significant school struggles
• Findings: IQ of 68 indicating need for assistance
• Conclusion: Highlights necessity for early detection and intervention

Evolving Testing Methods

• Recent Developments:
  • Focus on equitable, accurate assessments
  • Differentiated tests for various groups