Day 139 of 150 Speed Difficulty 6/10
Five decades of speed–IQ research: small-to-moderate, but robust
Quick answer
Five decades of speed–IQ research: small-to-moderate, but robust. Today's question (Speed of information processing and intelligence) asks about a finding from Sheppard, L. D., & Vernon, P. A. in 2008. The correct option is Moderate, robust across many tasks (RT, inspection time, evoked-potential latencies), and broadly comparable in size to working-memory–IQ correlations — full explanation, primary source, and glossary cross-links below.
Today's question
Sheppard & Vernon's (2008) meta-analytic review of speed of information processing and intelligence concluded that the speed–IQ relationship is:
Reveal the answer and explanation
Correct: B — Moderate, robust across many tasks (RT, inspection time, evoked-potential latencies), and broadly comparable in size to working-memory–IQ correlations
Sheppard & Vernon (2008) reviewed roughly 50 years of correlations between speed measures (simple and choice RT, inspection time, evoked-potential latencies, mental scanning) and psychometric intelligence. Across a wide variety of paradigms and samples, speed measures show small-to-moderate negative correlations with g (faster, higher IQ), with mean correlations around r = -0.2 to -0.4. The associations are robust to different reliability corrections and broadly similar in magnitude to working-memory–IQ correlations. The review reinforced processing-speed as a foundational individual-difference construct without claiming it singularly explains intelligence.
About the source
Sheppard, L. D., & Vernon, P. A. (2008). Intelligence and speed of information-processing: A review of 50 years of research. Personality and Individual Differences, 44(3), 535–551.
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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