cylinder turning behind a screen with a narrow window, so that one item at a time appears for a fixed interval. It made verbal learning a timed, repeatable procedure, and for about seventy years it was the standard apparatus of memory research.

what it is

Ebbinghaus had learned his syllable lists alone, reading at the beat of a metronome or a watch (Ebbinghaus, 1885). At Göttingen, G. E. Müller and Friedrich Schumann described a rotating-drum apparatus that exposed items at a controlled rate to a participant who was not the experimenter, together with rules for constructing lists of nonsense syllables (Müller & Schumann, 1894). Drums driven by clockwork and later by electric motors spread to laboratories everywhere.

what it made possible

Exposure time, order and pacing were now fixed by the machine, which made the anticipation method practical: the participant tries to say each item before it appears. With it Müller & Pilzecker (1900) studied interference between lists and proposed that memories need time to set, which they called consolidation (Lechner, Squire & Byrne, 1999) [paraphrase, not a quotation].

what's contested

The drum stood for a programme: memory studied as the formation of associations between meaningless items under strict control. Bartlett attacked that programme directly, arguing that stripping out meaning removed the thing to be explained; the defenders' answer was that without control there is no measurement. See the Bartlett archive page.

methodological critiques

Nonsense syllables were never as meaningless as intended: people find associations in them, and later researchers had to scale syllables for their "association value". Rote serial learning also proved a poor model of how people remember events, which is why it faded after the 1960s.

later reception

The drum was replaced by slide projectors and then computers, but its logic survives in every experiment that shows one item at a time on a screen at a fixed rate. Ebbinghaus's curve, measured without it, still replicates (Murre & Dros, 2015).

References

1. Ebbinghaus (1885). Über das Gedächtnis. Leipzig: Duncker & Humblot. English translation by H. A. Ruger & C. E. Bussenius, Memory: A Contribution to Experimental Psychology, Teachers College, Columbia University, 1913; transcribed at Classics in the History of Psychology. psychclassics.yorku.ca/Ebbinghaus/index.htm
2. Müller & Schumann (1894). Experimentelle Beiträge zur Untersuchung des Gedächtnisses. Zeitschrift für Psychologie und Physiologie der Sinnesorgane.
3. Müller & Pilzecker (1900). Experimentelle Beiträge zur Lehre vom Gedächtniss. Zeitschrift für Psychologie, Ergänzungsband 1.
4. Lechner, Squire & Byrne (1999). 100 Years of Consolidation— Remembering Müller and Pilzecker. Learning & Memory. doi:10.1101/lm.6.2.77
5. Bartlett (1932). Remembering: A Study in Experimental and Social Psychology. Cambridge: Cambridge University Press. (No free stable copy that we could verify; the scanned copies we found are lending-only.)
6. Murre & Dros (2015). Replication and Analysis of Ebbinghaus’ Forgetting Curve. PLOS ONE. doi:10.1371/journal.pone.0120644

see also