Unit 2.8: Intelligence and Achievement:n Stability of, and Influences on, Intelligence

Test Reliability Techniques
- Test-Retest: Mr. Russd's technique for assessing reliability by administering the same test to students twice, a week apart.

Flynn Effect:
- Definition: Refers to the observed phenomenon of increasing IQ scores in populations over time, across generations.
- Explanation: Indicates a rise in intelligence test performance across time and cultures.
Intelligence Test Measurements:
- A bell-shaped curve represents the normal distribution of intelligence scores.
- Standardization is essential for uniform testing procedures to ensure consistent results.

2.8-9: Explain the stability of intelligence test scores over a lifespan.
2.8-10: Discuss aging's effect on crystallized intelligence (Gc) and fluid intelligence (Gf).
2.8-11: Analyze twin and adoption studies' insights into intelligence's nature.
2.8-12: Evaluate environmental influences on cognitive development.

Researchers explore the consistency of intelligence through time and the balance between genetic nature and environmental nurture.
Age-related questions about intellectual capacity: Do intellectual abilities deteriorate with age, or do they remain constant?

Cross-Sectional Studies:
- Involve studying different age groups at a single point in time.
- Results may reflect differences in education and socio-economic backgrounds between cohorts (e.g., comparing 30-year-olds and 70-year-olds).
Longitudinal Studies:
- Follow the same group of people across multiple points in time, highlighting changes and stability in intelligence.
- Potential issue: Participants who complete the study may be healthier and more intelligent than those who drop out, impacting results.

Intelligence typically remains stable or even increases due to repeated exposure to testing and learning opportunities.
Ian Deary's research retesting 80-year-olds on intelligence tests taken at age 11 shows a significant correlation (+0.66) between scores, indicating strong score stability over time.

Definitions:
- Crystallized Intelligence (Gc): Accumulated knowledge and verbal skills, which tend to increase with age.
- Fluid Intelligence (Gf): Ability to reason and solve novel problems, which generally declines with age.
Aging affects cognitive abilities; while recall and processing speed decrease, accumulated knowledge generally increases.

Higher intelligence is linked to better health outcomes and longevity (Cadar et al., 2020; Geary, 2019).
Proposed explanations for this correlation:
1. Higher intelligence facilitates better education and healthier environments.
2. Intelligence encourages healthier lifestyle choices (diet, exercise).
3. Early life health conditions can influence both intelligence and health.
4. A well-functioning nervous system may promote both intelligence and longevity.

Heritability: The extent to which variation in intelligence scores among a group can be attributed to genetic factors, estimated between 50% to 80%.
- Explanation: This percentage refers to variance among individuals within a group, not to an individual's intelligence.
- Conditions: With more equal environments, heritability of intelligence increases.
- Different environments can skew interpretations of genetic contributions.

Identical twins raised apart show high similarities in intelligence, reinforcing the genetic component of intelligence.
Intelligence is polygenetic, influenced by multiple genes, as no single 'intelligence gene' has been identified.

Findings suggest that shared environments, such as those experienced by adopted children, can modestly impact intelligence outcomes.
Positive impacts of stable, enriched environments for children from poverty into financially secure homes can improve IQ scores.
Over time, adopted children's verbal abilities trend toward those of their biological parents rather than adoptive parents, showing genetic influence.

Growth Mindset: The belief that intelligence can be developed through effort and learning.
- Fixed Mindset: The belief that intelligence and abilities are static.
Research shows that fostering a growth mindset can encourage resilience and increase academic achievement.

Dramatic improvements in intelligence can be observed in children exposed to enriched environments, yet no evidence suggests extreme environments can guarantee genius-level intellect.
Balanced interventions are crucial to nurture both genetic and environmental factors, aiding in optimal cognitive development.

IQ Test Score Stability:
- Begins at age 4, becoming increasingly predictive of future scores by age 11.
Age and Intelligence Relationship:
- Age-related variations depend on the type of intelligence being assessed and the methods of assessment utilized.

Practical Examples in Class Assignments:
- Utilize case studies and apply methodology differences in researchers' approaches to intelligence assessment.
- Analyze case studies similar to Hunt's findings demonstrating the importance of an enriched caregiving environment for cognitive development.