Forgetting Curve

The general and predictable pattern of the process of forgetting learned information is called the forgetting curve.

Psychologists have been interested in the processes of learning and forgetting since the nineteenth century. The researcher who pioneered this field, Hermann Ebbinghaus (1850–1909), invented the nonsense syllable in order to be able to assess pure learning, or learning free of meaning. He also assessed the rate at which new information was forgotten. Serving as his own subject, the scientist learned a large number of nonsense syllables. By using material with little or no meaning, Ebbinghaus tried to create a learning situation that was free of prior knowledge. No association or context should exist for nonsense words. They are not embedded in memory before a subject encounters them in a learning paradigm.

The way that humans forget is highly predictable, following what psychologists call the forgetting curve. When people acquire knowledge, much of their forgetting occurs right away. Ebbinghaus discovered that a significant amount of information was forgotten within 20 minutes of learning it; over half of the nonsense material he learned was forgotten within an hour. However, although subjects forget almost twothirds of the material they learn within a day, memory of the material does not decline significantly beyond that period. In other words, if information is retained for a day or more, the knowledge is permanently embedded in memory.

Ebbinghaus's forgetting curve for nonsense words is more dramatic than a forgetting curve would be for meaningful material. When learners can connect new information with old information, they still may forget what was learned, but the amount and speed of forgetting is likely to be less than what Ebbinghaus experienced with his lists of nonsense syllables.

See also Ebbinghaus, Hermann; Learning ; Memory .



Aamodt, Sandra, and Sam Wang. Welcome to Your Brain: Why You Lose Your Car Keys but Never Forget How to Drive and Other Puzzles of Everyday Life. New York: Bloomsbury, 2008.

Anderson, John R., and G. H. Bower. Human Associative Memory. Hoboken, NJ: Taylor & Francis, 2014.

Clark, Ruth Colvin, and Richard E. Mayer. E-Learning and the Science of Instruction: Proven Guidelines for Consumers and Designers of Multimedia Learning. San Francisco: Pfeiffer, 2008.

Danziger, Kurt. Marking the Mind: A History of Memory. Cambridge, UK: Cambridge University Press, 2008.

Dror, Itiel E. Technology-enhanced Learning and Cognition. Philadelphia: John Benjamins, 2011.

Ebbinghaus, Hermann. Memory: A Contribution to Experimental Psychology. New York: Dover, 1964.

Haselgrove, Mark, and Lee Hogarth. Clinical Applications of Learning Theory. Hove, UK: Psychology Press, 2012.

Klein, Stephen B. Learning: Principles and Applications. Thousand Oaks, CA: SAGE, 2012.

Klingberg, Torkel. The Overflowing Brain: Information Overload and the Limits of Working Memory. Oxford: Oxford University Press, 2009.

Luck, Steven J., and Andrew Richard Hollingworth. Visual Memory. Oxford: Oxford University Press, 2008.

Raedt, Luc de. Logical and Relational Learning. Berlin: Springer, 2008.

Rudy, Jerry W. The Neurobiology of Learning and Memory. Sunderland, MA: Sinauer, 2008.

Wills, A.J. New Directions in Human Associative Learning. New York: Psychology Press, 2012.