Chapter 9: Intelligence and IQ testing

Intelligence and IQ Testing

9.1: What Is Intelligence? Definitional Confusion

9.1a Identify different models and types of intelligence.

  • Definition Issues: Psychologists struggle to define intelligence precisely. Notable sources of confusion regarding intelligence arise from the differing definitions and perspectives in psychology.

  • Cooper (2015), Sternberg (2003b), Sternberg & Detterman (1986): Indicate the ongoing debate in defining intelligence.

  • Edwin Boring (1923): Defined intelligence as what intelligence tests measure. This perspective lessens the burden of definition but does not clarify what distinguishes smart from less smart individuals.

  • Sir Francis Galton (1822-1911): Suggested intelligence is linked to sensory capacity, positing that individuals with superior sensory abilities acquire more knowledge from the environment.

    • Laboratory Tests: Galton administered a range of 17 sensory tests to over 9,000 participants to quantify sensory abilities.

    • Limitations: Later research demonstrated no strong correlation between various sensory abilities and overall intelligence, challenging Galton's theories.

  • Alfred Binet & Théodore Simon: Developed the first objective psychological test in 1904 with the intent of identifying children needing special educational assistance. They assessed higher mental processes through tasks focused on reasoning and understanding, fundamentally shifting the focus from mere sensory capacity to more abstract cognitive abilities.

    • Tasks Included:

      • Naming objects

      • Generating meanings for words

      • Completing sentences

      • Finding similarities among objects

    • Early Definitions: Resulted in a consensus that intelligence involves abstract thinking, reasoning, and adaptation to novel situations.

    • 1921 Consensus Definition by Experts:

      • Reason abstractly

      • Adapt to novel circumstances

      • Acquire knowledge

      • Benefit from experience

  • Cultural Perspectives: Intelligence conceptualization varies across cultures; for example, Americans generally equate intelligence with reasoning ability and rapid learning, while others (e.g., some Eastern cultures) associate it with wisdom and social harmony.

9.1b Describe the connection between intelligence and both brain size and efficiency.

  • Brain Size Correlation: Research indicates a correlation of about 0.3 to 0.4 between brain volume measured by MRI and general Intelligence Quotient (IQ), challenging the long-standing notion that greater brain size does not equate to higher intelligence within a species.

  • Efficiency of Brain Functioning: Studies indicate individuals with higher IQs may have more efficient brains, showing less activity during tasks compared to those with lower IQs; hence, implying that intelligence may be tied to how effectively the brain processes information rather than size alone.

  • Functional Studies: Tasks activating the prefrontal cortex—linked to executive functions like planning and impulse control—contribute significantly to intelligence, suggesting a localized relationship in brain structure to cognitive abilities.

  • The Paradox: For instance, Einstein’s brain was smaller than average, yet it displayed unique structural features such as a wider parietal cortex, which might correlate to his remarkable capacities in spatial reasoning.

9.2: Intelligence Testing: The Good, the Bad, and the Ugly

9.2a Determine how psychologists calculate IQ.

  • Historical Understanding of IQ:

    • Lewis Terman (Stanford-Binet IQ Test): Developed from Binet and Simon's work, it established norms to compare individual scores against age-based averages.

    • Wilhelm Stern’s Formula: Formulated IQ as (Mental Age / Chronological Age) x 100.

      • Critical Flaw: Mental age levels off around age 16, leading to decreasing IQ scores in older individuals according to Stern's formula.

    • Modern Approach: Uses deviation IQ where a score of 100 reflects average performance for age groups, eliminating the issue faced by Stern’s method.

9.2b Explain the history of misuse of intelligence tests in the United States.

  • Eugenics Movement:

    • Early IQ tests misapplied to classify immigrants and other populations created harmful societal impacts.

    • Poor assumptions around intelligence led to discriminatory policies that favored certain racial and social groups, and this misuse has left a lasting stigma surrounding IQ testing.

9.2c Describe tests of intelligence used today and evaluate the reliability and validity of IQ scores.

  • Common Tests:

    • Wechsler Adult Intelligence Scale (WAIS-IV): Widely used for adult assessment.

    • Wechsler Intelligence Scale for Children (WISC-V): Adapted for youth.

  • Stability and Predictive Validity:

    • IQ scores, especially in adults, have high reliability (around 0.95 test-retest reliability).

    • Predictive of academic success and other real-world outcomes, although influences from motivation and other environmental factors are also critical.

9.2d Distinguish the unique characteristics of intellectual disability and genius.

  • Intellectual Disability Characteristics: Based on three factors:

    1. Onset prior to adulthood

    2. IQ below ~70

    3. Inadequate adaptive functioning

  • Genius Characteristics:

    • As evidenced in Terman's study, individuals can reach significant achievements and often maintain functionality despite high IQs.

9.3: Genetic and Environmental Influences on IQ

9.3a Explain how genetic influences can be determined from family, twin, and adoption studies.

  • Family Studies:

    • Correlational evidence indicates higher similarity in IQ among closely related individuals, but cannot differentiate between genetic and environmental factors.

  • Twin Studies:

    • Show significant genetic influence on IQ estimates, with higher correlations among identical twins compared to fraternal twins (correlations often around 0.7-0.8 for identical and 0.3-0.4 for fraternal twins).

  • Adoption Studies:

    • Provide insights into genetic versus environmental contributions to intelligence by comparing adopted children's IQs with their biological versus adoptive parents.

9.3b Identify potential environmental influences on IQ.

  • Factors: Includes quality of schooling, poverty levels, nutrition, all which significantly affect IQ scores and cognitive abilities, highlighting the interplay of environmental context on intelligence development.

9.4: Group Differences in IQ: The Science and the Politics

9.4a Identify similarities and differences in mental ability between men and women.

  • Overall IQ: Findings indicate little or no average differences between men and women; however, men show greater variability in IQ scores.

  • Specific Abilities:

    • Women often excel in verbal tasks.

    • Men typically perform better on spatial tasks.

9.4b Evaluate the evidence concerning racial differences in IQ.

  • Disparities: Average IQ scores suggest differences across races (e.g., African Americans often score lower than Caucasian Americans), but substantial overlap exists between distributions.

  • Cautions Against Genetic attributions: Other factors, such as socioeconomic status and access to education, largely explain these differences.

  • Implications: Racial differences in IQ may reflect broader societal inequalities and not inherent abilities.

9.5: The Rest of the Story: Other Dimensions of Intellect

9.5a Describe how creativity and emotional intelligence relate to intelligence.

  • Creativity: Generally associated with novel and successful outcomes; requires both divergent and convergent thinking abilities. Creativity measures correlate weakly with IQ, emphasizing the multifaceted nature of intelligent behavior.

  • Emotional Intelligence (EQ): Encompasses awareness and regulation of one's emotions as well as understanding emotions in others. While beneficial, emotional intelligence does not always correlate strongly with IQ.

9.5b Explain why intelligence doesn’t protect us from errors in thinking.

  • Wisdom: Regarded as the application of intelligence for the common good, reflecting a more complex interplay of cognitive and emotional factors than IQ alone can capture. Even highly intelligent individuals can be susceptible to cognitive errors and biases.

Summary

The complexities surrounding intelligence cannot be attributed solely to IQ measurements. The discussion of intelligence encompasses a range of attributes, including emotional intelligence, the impact of creativity, the social context in which individuals exist, and the environmental factors that can significantly influence cognitive outcomes.