Intelligence lecture (10/30, 2.8)

Intelligence is not a single factor; it is multifaceted.
An individual can exhibit strengths in one area and weaknesses in another.
The definition of intelligence is culturally constructed, varying from one society to another.
- Example: In farming communities, practical agricultural knowledge may be valued more than academic knowledge.

Francis Galton, cousin of Charles Darwin, was a pioneering figure in the study of intelligence.
He established the first intelligence test focused on four specific areas:
- Reaction time
- Sensory acuity
- Muscular power
- Body proportions
Despite efforts, Galton's quest for a simple IQ test was unsuccessful.
His work introduced the concept of nature versus nurture in intelligence, linking heredity to genius.
- Book: "Heredity Genius" reflecting historical and psychological insights into intelligence research.

The modern intelligence movement began in the early 20th century when France mandated education for all children.
The French Minister of Education commissioned Alfred Binet to devise a way to measure children's learning capacities.
Binet's goal was to find each student's mental age, which is defined as:
- Mental Age: The level of performance associated with a typical chronological age.
Binet and Simon assumed all children follow the same developmental trajectory but at different rates.
- Example: A "dull" child might demonstrate the mental age of a younger child, whereas a bright child might show a higher mental age.
- Illustrative example: An average nine-year-old has a mental age of 9, a dull nine-year-old has a mental age of 7, and a bright nine-year-old has a mental age of 11.

Lewis Terman adapted Binet's test at Stanford University, enhancing it for California schoolchildren and various ages.
Terman's version is known as the Stanford-Binet test.
The test aimed to measure a broader spectrum of intelligence and included a superior range of abilities.

IQ, or Intelligence Quotient, is defined as:
- IQ = (Mental Age / Chronological Age) × 100
- This method is effective for children but not for adults; hence, modern tests assess performance relative to other individuals of the same age.
Average IQ score is set at 100, with about two-thirds of test-takers scoring between 85 and 115.
- Visual: Bell curve representation in intelligence testing.

Achievement Tests: Assess knowledge and skills that have been acquired.
Aptitude Tests: Designed to predict future performance or capacity to learn.
- Example: Correlation noted between IQ scores and SAT scores, suggesting a strong positive correlation (approximately 0.9).

Two prominent intelligence scales used:
- Wechsler Adult Intelligence Scale (WAIS)
- Wechsler Intelligence Scale for Children (WISC)
Both scales consist of multiple subtests assessing various cognitive abilities including:
- Verbal comprehension
- Memory
- Perceptual organization
- Working memory
- Processing speed
The scales help identify specific cognitive strengths and weaknesses in educational and therapeutic contexts.

Standardization: Refers to establishing uniform testing procedures and comparing scores with pretested groups.
Reliability: The consistency of test results over time or different forms of the test; high reliability is essential.
- Example: Wechsler and Stanford Binet have high reliability, with coefficients around 0.9.
Validity: Measures the extent to which a test accurately predicts or assesses what it claims to.
- Content Validity: How well a test samples the intended behavior.
- Predictive Validity: The success with which a test predicts future performance.

The question of intelligence stability depends on the assessment method used.
Cross-Sectional Studies: Comparing different age groups at one time indicates reasoning ability decreases with age.
Longitudinal Studies: Assess the same individuals over time suggest reasoning abilities remain stable or potentially improve.
Different types of intelligence (crystallized vs fluid) can also change differently with age.
- Crystallized Intelligence: Knowledge and skills accumulated over time; tends to increase with age and decline slowly.
- Fluid Intelligence: Speed and abstract reasoning abilities; tends to decline sharply starting in late adulthood.

Studies suggest that women scoring in the highest IQ percentiles tend to live longer than those in the lowest.
- Possible reasons include better socioeconomic status, education, access to healthcare, healthy living habits, and prenatal factors.
Genetics play a significant role in influencing intelligence.
- Polygenic Nature of Intelligence: Intelligence influenced by many genes, each contributing minimally to overall variations.
Heritability: The extent to which variations in intelligence can be attributed to genetics, generally estimated between 50% to 80%.

Early interventions and educational opportunities can significantly affect intelligence development.
Programs like Head Start aim to provide educational opportunities for children from disadvantaged backgrounds.
Although early educational interventions yield positive effects, these effects may diminish as children age.
Growth Mindset: The belief that intelligence can be developed versus a fixed mindset that views intelligence as static.

Many sociodemographic factors influence performance in intelligence assessments.
Behavioral patterns can vary by gender, with females excelling in spelling and verbal skills and males in certain mathematical and spatial abilities. - Example: Males may outperform females in complex math, though females can perform just as well in straight computation.
Controversy exists in debates over racial differences in IQ, often conflating test performance with intelligence. - Possible factors include cultural bias in testing instruments and social influences affecting performance.
Stereotype Threat: A self-confirming bias whereby individuals perform worse due to negative stereotypes associated with their identity.

Savant Syndrome: The condition characterized by exceptional ability in a specific area despite limitations in other areas. - Example: Individuals with savant syndrome may have advanced mathematical capabilities but struggle with everyday tasks.
Autistic Savant: Often linked to autism, though not exclusive to it; savants may show extensive skills in unique fields such as art or computation.
Films like "Rain Man" illustrate the complex capabilities of savants, highlighting their unusual skill sets compared to their general cognitive skills.