Hermann Ebbinghaus
Hermann Ebbinghaus was a German psychologist who pioneered the experimental study of memory. Ebbinghaus discovered the forgetting curve and the spacing effect. He was the first person to describe the learning curve. He was the father of the neo-Kantian philosopher Julius Ebbinghaus.
Early life
Ebbinghaus was born in Barmen, in the Rhine Province of the Kingdom of Prussia, as the son of a wealthy merchant, Carl Ebbinghaus. Little is known about his infancy except that he was brought up in the Lutheran faith and was a pupil at the town Gymnasium. At the age of 17, he began attending the University of Bonn, where he had planned to study history and philology. However, during his time there he developed an interest in philosophy. In 1870, his studies were interrupted when he served with the Prussian Army in the Franco-Prussian War. Following this short stint in the military, Ebbinghaus finished his dissertation on Eduard von Hartmann's Philosophie des Unbewussten and received his doctorate on 16 August 1873, when he was 23 years old. During the next three years, he spent time at Halle and Berlin.Professional career
After acquiring his PhD, Ebbinghaus moved around England and France, tutoring students to support himself. In England, he may have taught in two small schools in the south of the country. In London, in a used bookstore, he came across Gustav Fechner's book Elemente der Psychophysik, which spurred him to conduct memory experiments. After beginning his studies at the University of Berlin, he founded the third psychological testing lab in Germany. He began his memory studies here in 1879. In 1885 — the same year that he published his monumental work, Über das Gedächtnis. Untersuchungen zur experimentellen Psychologie, later published in English under the title Memory: A Contribution to Experimental Psychology — he was made a professor at the University of Berlin, most likely in recognition of this publication. In 1890, along with Arthur König, he founded the psychological journal Zeitschrift für Physiologie und Psychologie der Sinnesorgane.In 1894, he was passed over for promotion to head of the philosophy department at Berlin, most likely due to his lack of publications. Instead, Carl Stumpf received the promotion. As a result of this, Ebbinghaus left to join the University of Breslau, in a chair left open by Theodor Lipps. While in Breslau, he worked on a commission that studied how children's mental ability declined during the school day. While the specifics on how these mental abilities were measured have been lost, the successes achieved by the commission laid the groundwork for future intelligence testing. At Breslau, he again founded a psychological testing laboratory.
In 1902, Ebbinghaus published his next piece of writing entitled Die Grundzüge der Psychologie. It was an instant success and continued to be long after his death. In 1904, he moved to Halle where he spent the last few years of his life. His last published work, Abriss der Psychologie was published six years later, in 1908. This, too, continued to be a success, being re-released in eight different editions. Shortly after this publication, on 26 February 1909, Ebbinghaus died from pneumonia at the age of 59.
Research on memory
Ebbinghaus was determined to show that higher mental processes could actually be studied using experimentation, which was in opposition to the popularly held thought of the time. To control for most potentially confounding variables, Ebbinghaus wanted to use simple acoustic encoding and maintenance rehearsal for which a list of words could have been used. As learning would be affected by prior knowledge and understanding, he needed something that could be easily memorized but which had no prior cognitive associations. Easily formable associations with regular words would interfere with his results, so he used items that would later be called "nonsense syllables". A nonsense syllable is a consonant-vowel-consonant combination, where the consonant does not repeat and the syllable does not have prior meaning. BOL and DOT would then not be allowed. However, syllables such as DAX, BOK, and YAT would all be acceptable. After eliminating the meaning-laden syllables, Ebbinghaus ended up with 2,300 resultant syllables. Once he had created his collection of syllables, he would pull out a number of random syllables from a box and then write them down in a notebook. Then, to the regular sound of a metronome, and with the same voice inflection, he would read out the syllables, and attempt to recall them at the end of the procedure. One investigation alone required 15,000 recitations.It was later determined that humans impose meaning even on nonsense syllables to make them more meaningful. The nonsense syllable PED turns out to be less nonsensical than a syllable such as KOJ; the syllables are said to differ in association value. It appears that Ebbinghaus recognized this, and only referred to the strings of syllables as "nonsense" in that the syllables might be less likely to have a specific meaning and he should make no attempt to make associations with them for easier retrieval.
Limitations
There are several limitations to his work on memory. The most important one was that Ebbinghaus was the only subject in his study. This limited the study's generalizability to the population. Although he attempted to regulate his daily routine to maintain more control over his results, his decision to avoid the use of participants sacrificed the external validity of the study despite sound internal validity. In addition, although he tried to account for his personal influences, there is an inherent bias when someone serves as researcher as well as participant. Also, Ebbinghaus's memory research halted research in other, more complex matters of memory such as semantic and procedural memory and mnemonics.Contributions
In 1885, he published his groundbreaking Über das Gedächtnis in which he described experiments he conducted on himself to describe the processes of learning and forgetting.Ebbinghaus made several findings that are still relevant and supported to this day. First, Ebbinghaus made a set of 2,300 three letter syllables to measure mental associations that helped him find that memory is orderly. Second, and arguably his most famous finding, was the forgetting curve. The forgetting curve describes the exponential loss of information that one has learned. The sharpest decline occurs in the first twenty minutes and the decay is significant through the first hour. The curve levels off after about one day.
The learning curve described by Ebbinghaus refers to how fast one learns information. The sharpest increase occurs after the first try and then gradually evens out, meaning that less and less new information is retained after each repetition. Like the forgetting curve, the learning curve is exponential. Ebbinghaus had also documented the serial position effect, which describes how the position of an item affects recall. The two main concepts in the serial position effect are recency and primacy. The recency effect describes the increased recall of the most recent information because it is still in the short-term memory. The primacy effect causes better memory of the first items in a list due to increased rehearsal and commitment to long-term memory.
Another important discovery is that of savings. This refers to the amount of information retained in the subconscious even after this information cannot be consciously accessed. Ebbinghaus would memorize a list of items until perfect recall and then would not access the list until he could no longer recall any of its items. He then would relearn the list, and compare the new learning curve to the learning curve of his previous memorization of the list. The second list was generally memorized faster, and this difference between the two learning curves is what Ebbinghaus called "savings". Ebbinghaus also described the difference between involuntary and voluntary memory, the former occurring "with apparent spontaneity and without any act of the will" and the latter being brought "into consciousness by an exertion of the will".
Prior to Ebbinghaus, most contributions to the study of memory were undertaken by philosophers and centered on observational description and speculation. For example, Immanuel Kant simply described recognition and its components. On the other hand, Sir Francis Bacon claimed that the simple observation of the rote recollection of a previously learned list wasn't useful to understanding memory. This dichotomy between descriptive and experimental study of memory would resonate later in Ebbinghaus's life, particularly in his public argument with former colleague Wilhelm Dilthey. However, more than a century before Ebbinghaus, Johann Andreas Segner invented the "Segner-wheel" and would use both by seeing how fast a wheel with a hot coal attached had to move for the red ember circle from the coal to appear complete. He proceeded to view the length of the after images.
Ebbinghaus's effect on memory research was almost immediate. With very few works published on memory in the previous two millennia, Ebbinghaus's works spurred memory research in the United States in the 1890s, with 32 papers published in 1894 alone. This research was coupled with the growing development of mechanized mnemometers.
The reaction to his work in his day was mostly positive. Psychologist William James called the studies "heroic" and said that they were "the single most brilliant investigation in the history of psychology". Edward B. Titchener also mentioned that the studies were the greatest undertaking in the topic of memory since Aristotle.