Efforts to explain forgetting date back to the late 18

Efforts to explain forgetting date back to the late 1800s, when psychological researchers began – slowly, at first – to incorporate mathematical tools into their experiments. The German psychologist Hermann Ebbinghaus studied his own powers of recall by memorising long series of nonsense syllables, then recording how well he remembered them as time elapsed. His ability to summon up this meaningless information, he discovered, sloped downward over time in a curved distribution: he lost most of his hard-won syllables quickly, but a small percentage of them persisted in his memory long after his initial memorisation efforts.