6/3/2015 PsycCRITIQUES: Remembering Ebbinghaus

Contemporary : A Journal of Reviews 1985, Vol. 30, No. 7, 519–523

Remembering Ebbinghaus

A Review of

Memory: A Contribution to by New York: Dover, 1964. 123 pp.

http://dx.doi.org/10.1037/023895

Reviewed by

Henry L. Roediger, III

This year marks the centennial of Ebbinghaus's (1885/1964) great book Über das Gedächtnis, 1 which records one of the most remarkable achievements in the of psychology. To prepare myself for writing this retrospective review, I conducted a haphazard poll of my colleagues and some advanced graduate students in the halls of my department. The main findings of this unscientific study are (a) everyone who has (or is near) a PhD in psychology has heard of Ebbinghaus; (b) most know he studied and invented nonsense syllables for the purpose; and (c) a few could relate the basic ideas of his relearning and savings measures of memory and his famous curve. Finally, (d) no one, aside from a very few "psychonomes," has ever read his marvelous book.

The knowledge of my respondents is accurate so far as it goes but depressingly incomplete. It is like summarizing Skinner's contributions by saying that he measured responses of pigeons, gave them food, and taught them how to play ping-pong. Several readings of Ebbinghaus's book have convinced me that he was one of psychology's foremost pioneers, ranking with (if not ahead of) others from his time who are remembered more favorably today. In this review I will try to capture briefly his major contributions—his basic aims, methodological innovations, and most important findings—from a contemporary perspective, discuss some common criticisms of his work, and provide an evaluation.

The aim

A first notable achievement is that Ebbinghaus chose to undertake the study of memory at all. Experimental psychology was a fledgling enterprise when Ebbinghaus began his research in the late 1870s. Philosophers such as Herbart had argued that an experimental science of higher mental processes was impossible, in principle. Ebbinghaus borrowed from Herbart theoretical ideas concerning formation of associations, but not this presupposition. Ebbinghaus himself seemed doubtful about prospects for the scientific study of memory. After detailing the inadequacies of folk knowledge concerning memory in Chapter 1, he ends by writing:

It remains to be proved whether, in spite of the clearest insight into the inadequacy of our knowledge, we shall ever make any actual progress. Perhaps we shall always have to be resigned to this. … If by any chance a way to deeper penetration into this matter should present itself, surely, considering the significance of memory for all mental phenomena, it should be our wish to enter that path at once. For at the very worst we should prefer to see resignation arise from the failure of earnest investigations rather than persistent, helpless astonishment in the face of their difficulties. (pp. 5–6)

Exactly how Ebbinghaus conceived his ideas and methods for studying memory is unclear; certainly he gives almost no inkling in his book. We know that he studied the British associationists' work in depth and that he discovered a copy of Fechner's (1860/1966) in a Paris bookstand. 2 His basic goal was to attempt a "" of remembering by applying its exact methods. He credits Fechner for his inspiration (Boring, 1950, p. 387), but Ebbinghaus's ingenious techniques are quite different from Fechner's psychophysical methods. In Chapter 2 Ebbinghaus http://psycnet.apa.org/index.cfm?fa=fulltext.printReview&uid=2006-06426-002&=eng 1/9 6/3/2015 PsycCRITIQUES: Remembering Ebbinghaus outlines "the possibility of enlarging our knowledge of memory" by the methods of natural science. There he discusses such issues as the ability to manipulate one factor while holding others constant, establishing sensitive and reliable measures, averaging over large numbers of observations, and the causes of error in measurements. But it is one thing to lay out general principles of how a scientific approach to memory should be conducted; it is quite another trick to develop suitable methods to accomplish this goal. Ebbinghaus's great genius was as a methodologist and experimentalist. I turn now to these contributions.

The methods

Chapters 2 through 4 of the book constitute what would today be called the Method section. In Chapter 2 Ebbinghaus lays out his general plan, in Chapter 3 he describes his specific procedures, and in Chapter 4 he evaluates the general utility of the results obtained. The achievements here are nothing short of astounding, for he brings forth a science of memory and associations where before had been only centuries of speculation. Ebbinghaus was a meticulous experimenter and provided detailed descriptions of his procedures and controls.

He chose serial as his task: reading aloud a series of nonsense syllables and repeating them back, all in time to a metronome. He continued learning until he could repeat a series one time perfectly and without hesitation. His materials were the famous nonsense syllables constructed to minimize the influence of prior knowledge.3 He wanted a relatively homogeneous set of materials, but he noted that even nonsense syllables exhibited an "almost incomprehensible variation" (p. 23) in the ease with which they could be learned. Serial learning was a natural task, for it seemed to capture the associationists' concept of a flow of associations, each succeeding one produced by associative connections (the "invisible threads," as he sometimes referred to them) binding the series together.

Perhaps the most ingenious aspect of Ebbinghaus's methods is his dependent measure, savings obtained in relearning a series. As Ebbinghaus noted, if one's criterion of memory is reproduction (which is often the situation today), then only two main outcomes are possible—Either one can reproduce the series or one cannot. But suppose that a poem is learned by heart and that when the learner is tested after half a year, "no effort at recollection is able to call it back again into consciousness" (p. 8). Can the memory for such an experience never be studied? Does any trace of the experience exist? The relearning/savings method permits an answer to this question, for the poem can be relearned and one can determine if the number of trials (or amount of time) to accomplish the relearning is smaller than in the original learning. Assuming savings is shown in relearning, its magnitude reflects the amount of information retained.

In most of the actual Ebbinghaus measured the number of trials or amount of time to learn a series of nonsense syllables or a poem, and then the trials (or time) to relearn it later, as a function of some independent variable such as number of repetitions of the original series. Savings could be measured either in absolute terms or relative to the amount of effort in original learning. Thus, savings permitted graded determination of retention even when material had been completely forgotten as determined by "introspective means"—that is, conscious attempts at . (Savings has somewhat fallen out of favor as a measure of retention these days, but it is still put to ingenious use and may be due for a resurgence [e.g., Kolers, 1976; Nelson, 1985].)

Another important contribution was Ebbing