Hermann Ebbinghaus and The Forgetting Curve

The forgetting curve illustrates the pattern of forgetting that occurs over time. The curve shows that initially there is a big drop in the amount of information retained, then the information remaining is forgotten more gradually over a long period of time.

Around 40% of information learned by a person is forgotten within twenty minutes. More than half of the information is forgotten within the hour. The rate then slows down significantly, and around 20% of the information is remembered 31 days later.

When learning takes place over time, for example revising for a French test every second night for two months, more of the information is retained. The rate still stays the same however, with more than half the information lost within the hour it is learnt.

Hermann Ebbinghaus (1850-1909) was a German psychologist, and the first man to scientifically study forgetting. He used himself as a participant, and made himself learn lists of nonsensical words, like roj and tiq. Each list had thirteen "words" in it.

To measure the amount of information remembered and learn the rate at which information is forgotten, he learned the words of one list until he could recall them all without making any mistakes. He would then wait for a specified amount of time before seeing how many of the words he could recall.

Ebbinghaus repeated this procedure multiple times, changing the amount of time between learning the list and reciting the list from anything between 20 minutes and 31 days. By plotting his results on a graph, he created what is now known as the forgetting curve.

Many others have since done experiments relating to the forgetting curve and retaining information, including:

• learning a new skill, such as flying a plane (Fleischman and Parker, 1962)
• learning a new language (Bahrick, 1984)
• learning cardio-pulmonary resuscitation (McKenna and Glendon, 1985)
• learning about psychology (Conway, Cohen and Stanhope, 1991)

The results across all of these experiments show a consistency in that all of the information forgotten follows the forgetting curve.

The better the initial learning was, the longer the material will be retained.

Slow learners and fast learners both forget information at the same rate, and the difficulty of the information learned does not appear to affect the rate either.