Cognitive Development in Adulthood (College Board AP® Psychology): Revision Note

Cognitive changes in adulthood

• Cognitive development does not stop at adolescence

  • Adults continue to experience significant changes in cognitive capabilities across the lifespan

• Two broad types of intelligence follow different developmental trajectories in adulthood:

  • Fluid intelligence: the ability to reason quickly, think flexibly, and solve novel problems

    • This tends to peak in early adulthood and gradually decline with age

      • E.g. an older adult may find it harder to learn a new software program or solve an unfamiliar logic puzzle than a younger adult

  • Crystallized intelligence: accumulated knowledge and expertise built through experience

    • This tends to remain stable or even increase through much of adulthood

      • E.g. an experienced doctor's diagnostic expertise and medical knowledge typically grows richer with age even as their processing speed slows

• As adults age, additional cognitive changes occur as part of normal aging:

  • Processing speed decreases: the rate at which the brain takes in, interprets, and responds to information slows progressively from early adulthood onward

    • E.g. an older adult may take longer to complete a familiar task not because they have forgotten how to do it but because the speed at which they process the steps has slowed

  • Attention also declines: older adults may find it harder to sustain focus or filter out irrelevant information compared to younger adults

• These changes (declining fluid intelligence, processing speed, and attention) are normal features of cognitive aging and are distinct from the pathological decline seen in dementia

• Cognitive aging is not simply a story of decline but involves a shifting balance between different types of ability

  • Older adults often compensate for reduced fluid intelligence by drawing on their greater crystallized knowledge and experience

Cognitive disorders in adulthood

• For some adults, cognitive decline goes beyond normal age-related changes and involves significant impairment

  • This is known as dementia

• Dementia is an umbrella term for a range of conditions characterized by progressive decline in memory, thinking, language, and the ability to carry out everyday tasks

  • Dementia results from damage to brain cells and their connections

    • It is not a normal part of aging

  • The most common form is Alzheimer's disease, which typically begins with difficulty forming new memories and gradually progresses to affect older memories, language, and personality

• Dementia has significant effects on behavior and mental processes:

  • Memory loss: particularly difficulty forming new long-term memories in the early stages

  • Impaired language: difficulty finding words or following conversations

  • Reduced executive function: difficulty planning, organizing, and making decisions

  • Changes in personality and social behavior as the disease progresses