Hermann Ebbinghaus

Hermann Ebbinghaus, a German psychologist, fundamentally changed how memory is studied by bringing it into the laboratory. He identified the forgetting curve, which shows how quickly learned information fades, and the spacing effect, which demonstrates that studying over intervals improves retention. He also became the first person to describe the learning curve. His son, Julius Ebbinghaus, became a noted neo-Kantian philosopher.

Ebbinghaus was born in Barmen, then part of Prussia’s Rhine Province, to a wealthy merchant named Carl. Raised Lutheran, he attended the local Gymnasium. At 17, he entered the University of Bonn intending to study history and philology, but his interests shifted toward philosophy. His studies paused in 1870 when he served in the Prussian Army during the Franco-Prussian War. After that brief service, he completed a dissertation on Eduard von Hartmann’s philosophy of the unconscious and earned his doctorate at age 23, on 16 August 1873. He then spent three years in Halle and Berlin.

After his PhD, Ebbinghaus supported himself by tutoring in England and France, possibly teaching at two small schools in southern England. In a London used bookstore, he found Gustav Fechner’s *Elemente der Psychophysik*, which inspired him to experiment on memory. He began his research at the University of Berlin, where he established the third psychological testing lab in Germany, after those of Wilhelm Wundt and Georg Elias Müller. His memory studies started there in 1879. In 1885, he published his landmark work, *Über das Gedächtnis* (later *Memory: A Contribution to Experimental Psychology*), and was made a professor at Berlin, likely because of this book. In 1890, he co-founded the journal *Zeitschrift für Physiologie und Psychologie der Sinnesorgane* with Arthur König.

In 1894, Ebbinghaus was passed over to lead Berlin’s philosophy department—probably because he had published little—and Carl Stumpf got the post. Ebbinghaus then moved to the University of Breslau (now Wrocław, Poland), taking a chair vacated by Theodor Lipps. At Breslau, he served on a commission studying how children’s mental ability declined over the school day. Though the specific measurement methods are lost, the commission’s successes laid groundwork for future intelligence tests. He also founded another psychological testing lab there. In 1902, he published *Die Grundzüge der Psychologie*, which was an immediate success and remained popular after his death. He moved to Halle in 1904, spending his final years there. His last work, *Abriss der Psychologie*, came out in 1908 and went through eight editions. On 26 February 1909, Ebbinghaus died of pneumonia at age 59.

Ebbinghaus aimed to prove that higher mental processes could be studied experimentally, countering the prevailing view. To control for confounding variables, he needed material that could be memorized without prior associations. Regular words would trigger existing knowledge, so he created “nonsense syllables”—consonant-vowel-consonant combinations with no prior meaning, where the consonant did not repeat and the syllable was not a real word (e.g., DAX, BOK, YAT). After discarding meaningful syllables, he had 2,300 such items. He would randomly draw syllables from a box, write them in a notebook, then read them aloud to a metronome’s beat with consistent inflection, and try to recall them. One single investigation required 15,000 recitations.