Hermann Ebbinghaus (1850-1909) single-handedly created the experimental study of memory. Working alone and serving as his own experimental subject, he memorized lists of nonsense syllables (consonant-vowel-consonant combinations like DAX, BUP, ZOL) and systematically measured how much he retained over varying time intervals. His 1885 monograph, On Memory (Über das Gedächtnis), reported results that remain among the most replicated and fundamental findings in psychology.
Key Discoveries
The forgetting curve: memory declines rapidly at first, then levels off — most forgetting occurs within the first hour, with a progressively slower decline thereafter. This exponential (or power-law) function has been replicated across materials, populations, and time scales. The learning curve: each successive study trial produces less incremental learning, following a negatively accelerating function. The spacing effect: distributed practice (spacing study sessions) produces better long-term retention than massed practice (cramming), one of the most robust effects in all of psychology. Overlearning: continued practice beyond the point of initial mastery strengthens retention.
Ebbinghaus's methodological contributions were as important as his empirical findings. He invented the nonsense syllable as a stimulus material to minimize the influence of prior associations. He developed the savings method (relearning) as a sensitive measure of residual memory. He used himself as a subject with extraordinary discipline, conducting experiments over years. Most importantly, he demonstrated that higher mental processes — previously considered beyond the reach of experiment — could be studied with the same quantitative precision as sensory processes.