One of the very first studies in human memory applying scientific processes was published by Hermann Ebbinghaus in 1885 with the essay Uber das Dedachtniss (Memory, A Contribution to Experimental Psychology (English translation title)). Ebbinghaus used himself as the subject in his experiments in learning lists of non-sense words (from a list of 2300 words). Based upon his experiments he described three important theories which can be helpful today in understanding the learning process. They are: 1) interference theory in which earlier learning is covered over by later learning, 2) trace decay is where images or knowledge suffers changes which alter its character, 3) forgetting involves a “crumbling” of various components as opposed to a general obscuring.
Ebbinghaus used himself as the subject of his experiments because he wanted complete control of motivation factors and an awareness of any possible distractions from his experiments. After creating lists of three-letter non-sense words he would read them out loud at a steady rate of 150 per minute and consistent intonation usually emphasizing every fourth. He would continue to read the lists with periodic tests until he was able to reproduce the list without hesitation, a perfect reproduction of the material. He also controlled for external factors such as time of day and personal levels of distractedness. After doing thousands of tests, he performed statistical analysis on his results.
The ability of humans to store information is enormous, however the rate of retention, ability to accurately recall, and rate of forgetting varies greatly and is the area of greatest concern when we look at learning methods. Ebbinghaus examined the rate of rote learning he experienced with his lists. One question he sought an answer to was the effect of repetition on the rate of learning. What was the relationship between practice (repetitions) and learning; how did more practice effect the outcome? What happens when a list was learned a second time; what was the residual impact of initial work on subsequent efforts?
To find the answer to these and many other types of questions he employed lists of non-sense words and practiced them for 8, 16, 24, 32, 42, 53, or 64 repetitions. He would then relearn these lists the next day measure the results. “Learned” is defined as one successful performance of the material by memory. The use of non-sense words was to reduce or eliminate any associative characteristics with meaningful words. The purpose of the study was to look at the rote learning of non-associative and non-sense syllables.
After looking at the rates of learning 16 syllable sequences with 8, 16, 24, 32, 42, 53, and 64 reps he found an average saving of 12 seconds in the re-learning after 24 hours for each repetition. A single repetition of about 7 seconds of work saved 12 seconds of work the next day.
Ebbinghaus also looked at the rate of forgetting (his famous “forgetting curve). A 13 syllable list was re-learned after a 20 min break through 30 day interval. The forgetting metric is the difference between the numbers of reps for the first trial minus the number for the second trial expressed as a percentage of the first trial. The retention rate was found to be after 1/3 hr 60%, 1 hr 45%, 8 hr 35%, 24 hr 34%, 2 days 30%, 5 days 28%, and 30 days 25%. Most of the forgetting occurred within the first 24 hours and even after 30 days enough memory remained to reduce the time it took to relearn the list by 25%.
Ebbinghaus also looked at the position a word appeared in the list and the consequences of its serial position on retention and re-learning. There are two functions he found present. Recency is the recall of recently learned material and primacy is the recall of the first learned. First studied material benefits from the lack of conflicting material and increased rehearsal.
This is a study of purely rote learning of non-associative/nonsense information. It doesn’t show the retention of associative or meaningful material. It does however provide a baseline of learning. Rote learning is the most mechanical learning process and represents learning at its most basic level.
Ebbinghaus showed, through his careful testing of his most reliable subject, himself, a model of learning which still informs our thinking nearly 150 years later. We see the relationship between learning effort and forgetting and learning effort and retention.
In upcoming articles I will look at several aspects of his work which I found helpful in understanding some of the basics of human memory which were relevant to my study at the piano. I know that some of you may find this stuff as dry as dead bones, but I hope at least a few may share some of the AHAAA moments I had as I learned something about how I learn.