Day 110 of 120 Speed Difficulty 5/10
Speeded-reasoning decline starts surprisingly early in adulthood
Quick answer
Speeded-reasoning decline starts surprisingly early in adulthood. Today's question (Adult cognitive-aging trajectory) asks about a finding from Salthouse, T. A. in 2010. The correct option is Begin in the third decade of life and proceed nearly linearly thereafter — full explanation, primary source, and glossary cross-links below.
Today's question
In his 2010 selective review of cognitive aging, Salthouse concluded that age-related declines on speeded reasoning tasks:
Reveal the answer and explanation
Correct: B — Begin in the third decade of life and proceed nearly linearly thereafter
Drawing on cross-sectional and longitudinal data, Salthouse (2010) reported that processing speed and several fluid abilities (reasoning, working memory, episodic memory) begin a steady decline in the early-to-mid 20s and continue to decline at roughly similar rates across the adult lifespan. The pattern contrasts with crystallized abilities (vocabulary, general knowledge), which improve into the 60s. The review tempered popular narratives that locate cognitive aging mainly in late life and reframed adult cognitive trajectories as a long, slow change rather than a late cliff.
About the source
Salthouse, T. A. (2010). Selective review of cognitive aging. Journal of the International Neuropsychological Society, 16(5), 754–760.
Every Cognition Bible question cites a primary source — a paper, book chapter, or monograph that exists, that we can point to on Google Scholar, and whose finding the question accurately summarizes. No fabricated authority strings, no name-drops without paper-level grounding.
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