AP Psychology Practice Test

Crystallized intelligence refers to the accumulated knowledge and skills that an individual has acquired over their lifetime, including vocabulary, facts, and the ability to apply this knowledge in problem-solving situations. As people age, their experiences, education, and life encounters contribute to an expansion of this type of intelligence. This continuous reinforcement of knowledge allows older adults to draw from a richer reservoir of information when confronted with new situations or challenges.

In contrast, fluid intelligence, which encompasses raw cognitive abilities such as problem-solving, reasoning, and processing speed, tends to decline with age. Physical functioning may also decline, particularly in older adults, due to various health factors or physical changes. The ability to reproduce is primarily associated with younger individuals, and reproductive capabilities diminish with age. Therefore, crystallized intelligence is the most accurate choice for what tends to increase with age.