Stability does not mean immutability
People often maintain a similar relative position compared with peers, particularly from adolescence into adulthood. Stability is generally lower in early childhood because development is rapid.
Even a stable underlying ability will not produce the identical score every time. Every assessment is a sample of performance on a particular day.
Why scores may change
Changes can reflect both real development and testing variation.
- Education and cognitively demanding experience
- Illness, injury, sleep, stress, or medication
- Language development and familiarity with testing
- Different tests, updated norms, or normal measurement error
Retesting and practice effects
Repeating similar tasks too soon may improve performance through familiarity rather than a broad change in intelligence. Professional manuals specify retest guidance.
Learning and healthy habits can improve valuable skills even if a global IQ score changes little. The practical goal is better functioning, knowledge, and strategy—not chasing a number.
COMMON QUESTIONS
Frequently asked questions
Does IQ decrease with age?
Some speed and memory abilities may decline, while knowledge can remain stable or grow. Age-normed scores compare people with same-age peers.
Can studying raise IQ?
Education builds knowledge and thinking skills and may influence test performance, but effects vary.