Day 4 of 150 Memory Difficulty 3/10

Half of new memory is lost in the first 24 hours

Quick answer

Half of new memory is lost in the first 24 hours. Today's question (Forgetting curve) asks about a finding from Ebbinghaus, H. in 1885. The correct option is Within the first 24 hours after learning — full explanation, primary source, and glossary cross-links below.

Today's question

Ebbinghaus's forgetting curve (1885) shows the steepest memory loss occurs:

  1. A Within the first 24 hours after learning
  2. B Between days two and four
  3. C After about a week
  4. D Only after a month or more
Reveal the answer and explanation

Correct: A — Within the first 24 hours after learning

Ebbinghaus memorized lists of nonsense syllables and tested himself at varying intervals. Memory dropped sharply within hours — typically losing 50–60% of newly learned material in the first day — and then leveled off. The shape of the curve is the empirical foundation for spaced-repetition systems: review just before the curve collapses, and the next collapse comes much later.

About the source

Ebbinghaus, H. (1885). Über das Gedächtnis: Untersuchungen zur experimentellen Psychologie [Memory: A contribution to experimental psychology]. Duncker & Humblot.

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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