Hermann Ebbinghaus

Hermann Ebbinghaus was born on 24 January 1850 in Barmen, Prussia, to a wealthy merchant. He entered Bonn at seventeen but drifted from history to philosophy. After army service in the Franco-Prussian War he finished a dissertation on Hartmann's Philosophie des Unbewussten and earned his doctorate in August 1873, then tutored in England and France.

The decisive moment came in a London second-hand bookshop. He stumbled on Fechner's Elemente der Psychophysik and resolved to do for psychology what Fechner had done for psychophysics; his 1902 textbook bears the dedication "I owe everything to you." Back in Berlin he founded the third German psychology laboratory in 1879.

His instrument was the nonsense syllable - a CVC trigram carrying no prior meaning. He assembled some 2,300 and read them aloud to a metronome; one investigation required around 15,000 recitations. Published in 1885, On Memory unveiled the forgetting curve with steepest decay in the first twenty minutes, the learning curve, the serial-position effect, savings, and the spacing effect by which distributed practice beats cramming. James called the studies "heroic".

The limits matched the achievements. He was his own and only subject, and nonsense syllables were never fully meaningless. His methodological purity arguably delayed work on semantic memory. After leaving Berlin in 1893 he answered Dilthey's defence of descriptive psychology with a scathing reply for experimental science.

At Breslau he tracked children's mental capacity through the school day - work foundational for intelligence testing. His sentence-completion exercises were borrowed by Binet for the Binet-Simon scale, and he drafted the four-section research paper now standard worldwide. He died of pneumonia in 1909. He founded no school, yet the standard psychology paper and the spacing effect shaping how the world studies are both his.