Hall of Fame
Ebbinghaus (1850-1909)
Hermann Ebbinghaus, published a landmark book in 1885,
Uber das Gedachtis (On Memory), translated into English
in 1913. 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.
The whole idea of forgetting is still all too absent in education
and training with little or no real attention given to reinforcement
methods.
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:
|
Time |
Recall |
|
20
mins |
58% |
|
1
hour |
44% |
|
24
hours |
34% |
|
31
days |
21% |
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.
Distributed practice
A less well known, but just as significant, discovery was the benefits
of distributed 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.
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 recency. 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 Reagan, Clinton and Bush. 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.
The strength of opening events and summaries has long been recognised
in the design of learning materials.
Conclusion
Some argue that learning theory is fundamentally memory theory.
Ebbinghaus was the first great experimental investigator into memory,
using nonsense syllables to study learning and forgetting across
time. He covered most of the major findings in this area and many
of his central conclusions remain true and instructive. Of course,
there have been many refinements in memory theory and learning and
his investigations really only apply to simple rote learning. Other
semantic issues also matter along with attention, motivation and
other psychological factors.
http://psychclassics.yorku.ca/Ebbinghaus/
Bibliography
Translation of Memory: A Contribution to Experimental Psychology
by Hermann Ebbinghaus (1885)
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