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The researchers found quite dramatic
differences, with the one-hour-a-day group learning as much in 55 hours as
the four-hour-a-day group in 80. Moreover, the gradual group showed
greater retention of their skills when tested several months later.
Research has also
demonstrated that
people commonly over-estimate the value of massed practice, and tend not
to give due recognition to the value of spacing practice. This particular
study confirmed this, by finding that, notwithstanding their superior
performance, the gradual group were the least happy with the program - for
though they learned much more quickly in terms of hours, it took them many
more days (80 days at four hours a day is 20 days, but 55 hours at one
hour a day is 55 days).
Micro-distribution practice
What about practice
over much shorter intervals? Say you are learning vocabulary in a foreign
language - is it better to repeat a word twice in rapid succession, or to
space out the repetitions?
On the basis of the
distribution principle, the answer is clear. Go through your list once,
then repeat it. That way, every item will be maximally distant from its
own repetition. But the distribution principle isn't the only memory
principle at work here. The other principle is that of generation - that
if you produce the word for yourself, this will strengthen the connection
better than having the word given to you. And your likelihood of being
able to successfully recall the word is greater if you test it earlier.
So you have two
opposing principles at work here: one says maximise the time between
repetitions, the other says minimise it. Which wins? Well, neither.
They're both at work, so you need to take both into account, like this:
-
the first time,
test a new word after only a brief interval (your own experience is
best here, to tell you what length of interval is best for you)
-
on successive
recalls, gradually increase the interval (your aim is to find the
maximum interval at which you can reliably recall the word)
-
if you fail to
recall the word, shorten the interval; if you succeed, lengthen it
Distributed
practice in skill learning
The
distribution principle also applies to skill learning, although people are
probably even more reluctant to apply it. Practicing a skill in a
concentrated block seems to give better performance, and indeed it
does - at the time. The problem is, it doesn't lead to better long-term
learning.
Part
of the problem is that it makes you over-estimate how well you have
learned the skill. But most of that learning will fade quickly. To learn
the skill properly (i.e., for over the long term), you are best, not
simply to distribute your practice, but also practice the skill in the
context of a variety of different tasks. For example, if you were learning
to type, you could hammer away at one combination of keys (say, asdf)
thirty times, then you could move on to another sequence (jkl;) and repeat
that thirty times, and so on. But it would be better if you mixed the
sequences up.
It
is thought that practicing in this way works better because it requires
you to repeatedly
retrieve the motor program corresponding to each task. It also requires
you to differentiate the skills in terms of
their similarities and differences, which may be assumed to result in a
better mental conceptualization of those skills.
References
Baddeley, Alan. Your memory: A user’s guide.
(2nd ed.) London: Penguin Books, 1994.
Simon,
D.A. & Bjork, R.A. 2001. Metacognition in Motor Learning. Journal
of Experimental Psychology: Learning, Memory and Cognition, 27 (4).
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