Hermann Ebbinghaus (1850-1909) was born in Prussia and studied history and philology (historical linguistics) and then later philosophy. In 1873, at Berlin University, he was awarded his doctorate, after writing a dissertation on the unconscious. Ebbinghaus travelled during the years 1873-1878, during which in Paris he came across a book, Elements of Psychophysics by Gustav Fechner, describing the scientific study of the perception of sensory stimulation. On his return to Berlin, three years later, Ebbinghaus applied this approach to study memory. In 1880 he became a lecturer at Berlin University and in 1885 he published his monograph on memory, demonstrating to others that it was possible to use the experimental, quantitative approach to the study of mental phenomena. Nine years later, he moved to the university at Breslau where he conducted research on psychophysics (colour vision in particular) and educational psychology as well as on memory. He died of pneumonia in 1909.
Ebbinghaus was not the first to think about memory but is considered one of the first to study it scientifically in the late 19th century. He wanted to explore how long it would take to learn something, what factors would affect learning speed, how quickly would this learning be forgotten, and how quickly it could be relearned. He was the sole participant in his experiments and, to study memory objectively and avoid confounding variables, he devised stimulus material that he had not encountered before in his daily life and that had no meaning. He created thousands of nonsense syllables, i.e. consonant-vowel-consonant trigrams that could be pronounced but were meaningless such as TUV and BUX. One of his findings, that has been replicated by other researchers, is that with small retention intervals (the time between learning and testing) forgetting rate is quite rapid but after that is slows down and becomes more gradual with longer retention intervals. A lot of what he learned was forgotten within the first 24 hours but he was able to remember 30 days later much of what he could remember after 5 days. His work challenged the then prevalent view that higher mental processes could not be studied experimentally (e.g. Wilhelm Wundt) and he is considered a founder of modern experimental psychology.