George Miller is best known for
his paper ‘The magic number 7 plus and
minus 2’ (1956) which focused attention (literally) on a problem that
plagues teaching and learning, the danger of ‘cognitive overload’. For this
reason alone, he deserves mention. Short-term memory has a limited capacity and
this capacity can be seen as being dependent on ‘attention’ i.e. our ability to
attend to things in short-term memory. More than this Miller was one of the first to bring in cognitive information theory, famously saying the the mind had been brought back into psychology on the back of the machine.
Chunks
Miller started by identifying
relevant studies that show we remember ‘chunks’ of information. But what is a
‘chunk’? We can remember, on average, seven
randomised numbers but only six
letters and four or five words. Miller’s solution was to
posit clusters of chunks e.g. a word is a cluster of letters, a phrase a
cluster of words. But Miller’s definition proved inadequate. This problem, that
we remember different types of content differently giving variable sizes of
chunks, was to open up a whole field of experimental work that began to reveal
how short-term memory works. The concept of a ‘chunk’ has proved enduring and
useful in memory research.
Encoding
methods
Research by Bower (1970, 1972)
showed that meaning also played a role in chunking so that, for example,
TVFBIJFKCIAIBM is far more difficult to remember than TV FBI JFK CIA IBM.
Mnemonics, as chunks, can also be used to unpack larger amounts of information.
Gardener (1988) then showed the power of the ‘generative effort’, where
creating your own chunks, is even more effective.
Encoding
Of course, chunking is just one
form of encoding that increases retention, the organisation of material is
another, chunking categories logically and with relatively few numbers of items
in each category, increases recall, as do outlines. Imagery is another useful
form of encoding, which is why loci and peg-word systems have been used for
centuries to improve memory. In particular, movement and interaction between
images so that they do things to each other, were shown by Wollen, Weber &
Lowry (1972) to be particularly effective. Craig & Lockhart (1972)
popularised the word ‘elaboration’ for techniques such as paraphrasing,
summarising, highlighting and note taking, all of which improve recall.
Duration
Miller’s work also led to
research on the time we are able to hold attention in short-term memory. Waugh
and Norman (1965) found, in recall experiments, that this was around 18
seconds. However, if recognition, and not recall, is used this can stretch out
to 90 seconds (Lutz & Wuencsch 1989).
E-learning
and chunks
E-learning, with its learning
objects, nuggets and page-based delivery has long sought to chunk material to
make it more digestible and to increase encoding and retention. Chunked media
objects such as short videos, animations, examples and so on, have also been
part of the e-learning landscape. Attempts have even been made to determine
standards around reusable learning objects that can be re-assembled in
different orders and in different contexts and courses, like LEGO. The problem is
the conflict between usability and the flow and context of the learning
experience on one hand, and the fragmented nature of chunked learning objects
on the other. This has also led to standards such as SCORM, that some believe
traps designers in to producing learning objects and does not cope with more
complex entities such as simulation and games pedagogy.Conclusion
Miller, a pioneer in the information processing or computational
model of memory, set us on the path of defining the limits of short-term
memory, the gate through which attentive learning must pass. It proved to be
limited in time, capacity and the way we encode information. This has opened up
research on cognitive overload and a deeper exploration of what we now call
‘working’ memory and encoding through elaboration. The magic number ‘7’ may
have proved misleading, as our short-term register
often operates at a lower 3-4 register level, but the principle of cognitive
overload remains a limit on learning.
Bibliography
Miller,
G.A. (1956). The magical number seven, plus or minus two: Some
limits on our capacity for processing information.
Psychological Review, 63, 81-97. http://www.well.com/user/smalin/miller.html
Miller, G.A., Galanter,
E., & Pribram, K.H. (1960) Plans and
the Structure of Behavior. New York: Holt, Rinehart & Winston.
Miller G Psychology
Penguin
Bower G. H. (1970) Organisational factors in memory
Cognitive Psychology, 1, 18-46
Bower G. H. (1972) Mental imagery in associative learning
in Gregg L,W. Cognition in learning and memory New York, Wiley
Gardener (1988) Generation and priming effects in word
fragment completion Journal of Experimental Psychology: Learning, Memory
and Cognition 14, 495-501
Wollen, Weber & Lowry
(1972) Bizarreness versus interaction of
mental images as determinants of learning Cognitive Psychology, 3, 518-523
Craig F. I. M. & Lockhart R.S.
(1972) Levels of processing: A framework
for memory research, Journal of Verbal learning and Behaviour, 11, 671-684.
Waugh N. C. and Norman D. A.
(1965) Primary Memory, Psychological
Review, 72, 89-104.(1965)
Lutz J. & Wuencsch K.L. (1989)
Acoustic interference in a recognition task. The Journal of General Psychology,
116(4), 371-384
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