Raw IQ changes systematically across the human lifespan at the group level
the verdict
SUPPORTED
the evidence backs this
confidence 75/100
Intelligence and cognitive abilities change systematically across the human lifespan, showing distinct developmental peaks and aging trajectories for fluid versus crystallized domains.
Evidence for · 2
Are Age‐Related Differences in Sleep Associated With the Different Trajectories of Fluid and Crystallized Intelligence Across the Lifespan?
2026 · cited by 0
Paper 9 details how fluid and crystallized intelligence exhibit distinct, systematic trajectories across the lifespan, with fluid intelligence peaking in early adulthood and declining thereafter while crystallized intelligence behaves differently.
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More for · 1
Nonlinear Lifespan Trajectories of Memory and Fluid Reasoning: A Longitudinal GAMM Study
2025 · cited by 0
Paper 10 uses longitudinal modeling to demonstrate robust, systematic nonlinear age-related changes and declines in cognitive domains such as memory and fluid reasoning across adulthood.