Hermann
Ebbinghaus published a landmark book in 1885, Uber das Gedachtis (On Memory), translated into English in 1913. In
this he put the study of memory on a sure, scientific footing using rigorous
experiments, exploring retention and the effects of sequencing and patterns of
practice on memory. Indeed, most subsequent research into learning and memory
has been footnotes to his work.
Decay from memory
In
perhaps his most famous experiment, trying to remember syllable lists, he found
that after certain periods he remembered only a percentage of the original:
after 20 mins 58%, an hour 44%, 24 hours 34%, 31 days 21%. This was the
‘forgetting curve’. In other words, within a month, nearly 80% of the learned
content had been lost. But the real lesson was that most of the loss came in
the first few minutes. The distinction between short and long-term memory was
made, and it became clear that successful learning had to push knowledge from
short to long-term memory to be successful. Of course, it is not simply a
matter of practice and reinforcement, related meaning and the organisation of
the material are also important.
Spaced practice
A
less well known, but just as significant, discovery was the benefit of
distributed or spaced practice. Distributed practice is spread out over a period
of time, whereas massed practice takes place in one session. The spacing out of
practice seems to avoid fatigue effects and lead to more consolidation of
memory. Consolidation seems to be optimal after about 20 minutes, suggesting
that we should practice and reinforce learning after 15-20 minutes. This flies in the face of most teaching and instruction,
whether it be school lessons, lectures or ‘sheep-dip’ training courses. Much of
what passes for learning experiences are therefore wasted, as reinforcement
through spaced practice is neither planned nor executed.
Primacy and recency
Ebbinghaus
also discovered the serial position effect. In remembering lists, he observed
that people are far more likely to remember items at the start and end of
lists. These effects are called primacy and regency. It depends on the nature
of the material, the relationship between the material and users approach to
learning, but by and large the principle is that material from both ends of a
learning experience are retained more than the stuff in the middle. This has
been confirmed many times since.
Take
the example of the Presidents of the US. Most people remember Washington and
the more recent Bush and Obama. Incidentally, many people also remember Abraham
Lincoln, confirming another psychological effect in learning, the von Rector
effect (1933). He found that the more something stands out from the crowd, the
easier it is to remember. In a specific experiment by E.J Thomas in Studies in Adult Education (1972), it
was found that there was a massive dip in attention and recall from the middle
of lectures. In other words, in lectures and the classroom the effects of
primacy and recency are profound. Primacy, and especially recency, have also
opened up avenues of research, especially in providing clues for working
hypotheses on how working memory operates.
Conclusion
Some
argue that learning theory is fundamentally memory theory and if William James
is the father of psychology, Ebbinghaus is the father of memory theory. He was
the first, great experimental investigator into memory, and quickly saw that
most learning leads to forgetting. The whole idea of forgetting is still all
too absent in education and training with little attention given to
reinforcement methods and spaced practice. Most of the major findings in this
area were covered by him and many of his central conclusions remain intact and
instructive. Although his investigations really only apply to relatively, simple,
rote learning, he opened up avenues of inquiry that have led to astounding
progress in the psychology of memory.
Bibliography
Ebbinghaus,
Hermann (1885). Translation of Memory: A Contribution to Experimental
Psychology
3 comments:
Excellent post. You are building a great resource here. Any plans for a short book, with hypertext-style bold headings to cross-link themes and people? I'd get a copy! Interesting what Ebbinghuas says about lists. My mother always told me you forget the last of a list when recounting it to people - and I have found this to be pretty much universally true.
Interesting about being more likely to remember things at the beginning of a list and also link to Miller. I remember when I was at school our RE teacher told us we had to remember the names of the Books of the Old Testament. Why we were set this task I have absolutely no idea, always seemed pointless and still does. However, that was 40 years ago and I can still remember the first 8 books in the right order!
You look suspiciously like Ebbinghaus - compare the photos at the top of the post!!! Scary!
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