1. Intelligence Scores Over the Lifespan

2. Are Intelligence Scores Stable?
The research about IQ score stability has historically gone through 3 phases:
Phase 1: Cross-sectional Studies
Phase 2: Longitudinal Studies
Phase 3: It Depends

3. Are Intelligence Scores Stable?
Phase 1: Cross-sectional Studies
Early intelligence test researchers tested people of different ages
Younger people scored higher than older people
Their conclusion: “The decline of mental ability with age is a part of the general [aging] process of the organism.”

4. Are Intelligence Scores Stable?

5. Are Intelligence Scores Stable?
Phase 2: Longitudinal Studies
Psychologists began to test, then retest the same people several years later
Their findings showed intelligence remained stable until late life

6. Are Intelligence Scores Stable?

7. Are Intelligence Scores Stable?
Why the difference?
The cross-sectional studies that compared 70 year-olds to 30 year-olds inadvertently had built-in mistakes
Compared those who were raised in different eras, thus:
compared less educated with better educated
compared people raised in large families
compared less affluent with more affluent

8. Are Intelligence Scores Stable?
Phase 3: It Depends
Longitudinal studies may have their own problems, such as those who survive to old age may be bright & healthy, least likely to decline
Adjusting for loss of participants, interesting results occur
Depending on the trait (multiple intelligence), some decline others improve

9. Are Intelligence Scores Stable?
Crystallized intelligence, which is accumulated knowledge as reflected in vocabulary and analogy tests increase up to old age
Fluid intelligence, which is our ability to reason speedily and abstractly decreases around the twenties and thirties

10. Are Intelligence Scores Stable?

11. Are Intelligence Scores Stable?
Generally, as we age we lose recall memory and speed, but gain vocabulary knowledge
Older adults also show:
Less susceptibility to emotions affecting decision making
Increased social reasoning as evidenced by being able to take multiple perspectives and acknowledging limits

12. Accomplishments
Laura Ingalls Wilder published her first book at age 64
Nelson Mandela became president of South Africa at 76
Roget first published his thesaurus at 73
Colonel Sanders began KFC in his 60’s
Henry Ford created the assembly line at 60
“Aging is an issue of mind over matter.
If you don’t mind, it don’t matter.”

13. Intelligence Predictions from Early Life
With the exception of extremely impaired or very precocious children, intelligence tests before age 3 only moderately predict future aptitude
By age 4 performance on intelligence tests begin to predict adolescent and adult scores
Scottish longitudinal study of 11 year-olds began in 1932 readministered 70 years later and showed +.66 correlation.

14. Intelligence in Early Life

15. Intelligence in Early Life
Intelligence is correlated with living longer
Higher scoring 11 year-olds more likely to be living independently at age 77
Of the girls scoring in the highest 25 percent, 70% were still alive at age 76 compared to 45% of those scoring in the lowest 25 percent
(WWII prematurely ended the lives of many male test takers)

16. Extremes in Intelligence
Valid tests do discriminate.
Extremely low – Average – Extremely high

17. Extremes in Intelligence
To be labeled as having an intellectual disability (formerly mental retardation), a person must have low test scores and difficulty adapting to the demands of independent living.

18. Extremes in Intelligence
Intellectually disabled
Criterion 1
Test scores of 70 or below on IQ tests that have 100 as mean
Criterion 2: limitations in adaptive behavior
Conceptual skills
Social skills
Practical skills

19. Extremes in Intelligence
To be labeled as gifted, a person will score in the top 2% of the population, typically possessing an IQ of 130 or above.

20. Extremes in Intelligence
Intellectually gifted
Terman’s research demonstrated the gifted were socially well-adjusted, often skilled leaders, and above average in height, weight, and physical attractiveness.
Critics and proponents of gifted education programs agree that children have different gifts, whether math, verbal processing, music, art, or social leadership.