Structural and functional changes in the brain dictate the trajectory of cognitive abilities across infancy, childhood, adolescence, and aging.
- Neuroanatomical Correlates: Prefrontal cortex (PFC) maturation correlates directly with executive functions (working memory, cognitive flexibility, inhibitory control). Synaptic pruning during adolescence optimizes neural pathways, while myelination enhances processing speed.
- Fluid vs. Crystallized Intelligence: Raymond Cattell (1963) and John Horn distinguished between fluid intelligence ($G_f$—biologically based abstract reasoning, peaking in young adulthood) and crystallized intelligence ($G_c$—acquired knowledge and verbal skills, which remain stable or increase throughout adulthood).
- Methodological Paradigms: Longitudinal, cross-sectional, and sequential research designs are deployed to study age-related cognitive shifts, controlling for cohort effects (e.g., Schaie’s Seattle Longitudinal Study).