Memory
and Learning: Myths and Facts
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- Myth: It is
possible to produce everlasting memories. Even reputable researchers
use the term permastore (see: Prof. Harry Bahrick). It is a widely-held
belief that it is possible to learn things well enough to protect them
permanently from forgetting. Fact: It is possible to learn things
well enough to make it nearly impossible to forget them in lifetime.
Every long-term memory, depending on its strength, has an expected lifetime.
When the memory strength is very high, the expected lifetime may be
longer than our own lease on life. However, if we happened to get extra
200 years to live, no memory built in present life would remain safe
without repetition
- Myth: We never
forget. Some accelerated-learning programs claim that we never forget
what we learn. Knowledge simply gets "misplaced" and the key to good
memory is to figure out how to dig it out. Fact: All knowledge
is subject to gradual decay. Even your own name is vulnerable. It is
only a matter of probability. Strong memories are very unlikely to be
forgotten. The probability of forgetting one's name is like the probability
of getting hit by an asteroid: possible but not considered on a daily
basis
- Myth: Memory
is infinite. Fact: Anyone with basic computational understanding
of memory will call this claim absurd, but 50% of Americans still believe
the earth was created by God less than 10,000 years ago. We cannot even
hope to memorize Encyclopedia Britannica in lifetime. Because information
is stored in synapses which are finite, memory storage is naturally
finite too. Even worse, storing information long-term is not easy. Most
people will find it hard to go beyond 300,000 facts memorized in a lifetime
(with SuperMemo, 300,000 items is quite realistic though). For the other
extreme see: Memory overload may cause Alzheimer's
- Myth: Mnemonics
is a panacea to poor memory. Some memory programs focus 100% on
mnemonic techniques. They claim that once you represent knowledge in
an appropriate way, it can be memorized in a nearly-permanent way. Fact:
Mnemonic techniques dramatically reduce the difficulty of retaining
things in memory. However, they still do not produce everlasting memories.
Repetition is still needed, even though it can be less frequent. If
you compare your learning tools to a car, mnemonics is like a tire.
You can go on without it, but it makes for a smooth ride
- Myth: The more
you repeat the better. Many books tell you to review your materials
as often as possible (Repetitio mater studiorum est). Fact:
Not only frequent repetition is a waste of your precious time, it
may also prevent you from effectively forming strong memories. The fastest
way to building long-lasting memories is to review your material in
a precisely determined moments of time. For long memories with minimum
effort use spaced repetition (see SuperMemo)
- Myth: You should
always use mnemonic techniques. Some enthusiasts of mnemonic techniques
claim that you should use them in all situations and for all sorts of
knowledge. They claim that learning without mnemonic techniques is always
less effective. Fact: Mnemonic techniques also carry some costs.
Sometimes it is easier to commit things to memory straight away. The
pair of words teacher=instruisto in Esperanto is mnemonic on
its own (assuming you know the rules of Esperanto grammar, basic roots
and suffixes). Using mnemonic techniques may be an overkill in some
circumstances. The rule of thumb is: evoke mnemonic techniques only
when you detect a problem with remembering a given thing. For example,
you will nearly always want to use a peg-system to memorize phone numbers.
Best of all, mnemonic tricks should be a part of your automatically
and subconsciously employed learning arsenal. You will develop it over
a long run time with massive learning
- Myth: We cannot
improve memory by training. Infinite memory is a popular optimist's
myth. A pessimist's myth is that we cannot improve our memory via training.
Even William James in his genius book The Principles of Psychology
(1890) wrote with certainty that memory does not change unless for
the worse (e.g. as a result of disease). Fact: If considered
at a very low synaptic level, memory is indeed quite resilient to improvement.
Not only does it seem to change little in the course of life. It is
also very similar in its action across the human population. At the
very basic level, synapses of a low-IQ individual are as trainable as
that of a genius. They are also not much different from those of a mollusk
Aplysia or a fly Drosophila. However, there is more to
memory and learning than just a single synapse. The main difference
between poor students and geniuses is in their skill to represent information
for learning. A genius quickly dismembers information and forms simple
models that make life easy. Simple models of reality help understand
it, process it and remember it. What William James failed to mention
is that a week-long course in mnemonic techniques dramatically increases
learning skills for many people. Their molecular or synaptic memory
may not improve. What improves is their skill to handle knowledge. Consequently,
they can remember more and longer. Learning is a self-accelerating and
self-amplifying process. As such it often leads to miraculous results.
- Myth: Encoding
variability theory. Many researchers used to believe that presenting
material in longer intervals is effective because of varying contexts
in which the same information is presented. Fact: Methodical
research indicates that the opposite is true. If you repeat your learning
material in the exactly same context, your recall will be easier. Naturally,
knowledge acquired in one context may be difficult to recover in another
context. For this reason, your learning should focus on producing very
precise memory trace that will be universally recoverable in varying
contexts. For example, if you want to learn the word informavore,
you should not ask How can I call John? He eats knowledge for breakfast.
This definition is too context-dependent. Even if it is easy to remember,
it may later appear useless. Better ask: How do I call a person who
devours information?. Now, even if you always ask the same question
in the same context, you are likely to correctly use the word informavore
when it is needed. For more on encoding variability and spacing
effect see: Spaced repetition in the practice of learning
- Myth: Mind maps
are always better than pictures. A picture is worth a thousand words.
It is true that we remember pictures far better than words. It is true
that mind maps are one of the best pictorial representations of knowledge.
Some mnemonists claim that all we learn should be in the form of a picture
or even a mind map. Fact: It all depends on the material we learn.
One of the greatest advantages of text is its compactness and ease at
which we can produce it. To memorize your grandma's birthday, you do
not really need her picture. A simple verbal mnemonic will be fast to
type and should suffice. In word-pair learning, 80% of your material
may be textual and still be as good or even better than pictorials.
If you ask about the date of the Battle of Trafalgar, you do not need
a picture of Napoleon as an illustration. As long as you recall his
face at the sound of his name, you have established all links needed
to deduce relevant pieces of knowledge. If you add a picture of the
actual battle, you will increase the quality and extent of memorized
information, but you will need to invest extra minutes into finding
the appropriate illustration. Sometimes a simple text formula is all
you need
- Myth: Review
your material on the first day several times. Many authors suggest
repeated drills on the day of the first contact with the new learning
material. Others propose microspacing (i.e. using spaced repetition
for intervals lasting minutes and hours). These are supposed to consolidate
the newly learned knowledge. Fact: A single effective repetition
on the first day of learning is all you need. Naturally it may happen,
you cannot recall a piece of information upon a single exposure. In
such cases you may need to repeat the drill. It may also happen that
you cannot effectively put together related pieces of information and
you need some review to build the big picture. However, in the ideal
case, on the day #1 you should (1) understand and (2) execute a single
successful active recall (such as answering the question "When did
Pangea start breaking up?"). One exposure should then suffice to
begin the process of consolidating the memory trace
- Myth: Review
your material next day after a good night sleep. Many authors believe
that sleep consolidates memories and you need to strike iron while it
is hot to ensure good recall. In other words, they suggest a good review
on the next day after the first exposure. Fact: Although sleep
is vital for learning and review is vital for remembering, the optimal
timing of the first review is usually closer to 3-7 days. This number
comes from calculations that underlie spaced repetition. If we
aim to maximize the speed of learning at a steady 95% recall rate, most
well-formulated knowledge for a well-trained student will call for the
first review in 3-7 days. Some pieces must indeed be reviewed on the
next day. Some can wait as long as a month. SuperMemo and other computer
programs based on spaced repetition will optimize the length
of the first interval before the first review
- Myth:
Learn new things before sleep. Because of the research showing the
importance of sleep in learning, there is a widespread myth claiming
that the best time for learning is right before sleep. This is supposed
to ensure that newly learned knowledge gets quickly consolidated overnight.
Fact: The opposite is true. The best time for learning in a healthy
individual is early morning. Many students suffer from DSPS (see: Good
sleep for good learning) and simply cannot learn in the morning. They
are too drowsy. Their mind seems most clear in the quiet of the late
night. They may indeed get better results by learning in the night,
but they should rather try to resolve their sleep disorder (e.g. with
free running sleep). Late learning may reduce memory interference, i.e.
obliteration of the learned material by the new knowledge acquired during
the day. However, a far more important factor is the neurohormonal state
of the brain in the learning process. In a hormonal sense, the brain
is best suited for learning in the morning. It shows highest alertness
and the best balance between attention and creativity. The gains in
knowledge structure and the speed of processing greatly outweigh all
minor advantages of late-night learning
- Myth: Long sleep
is good for memory. Association of sleep and learning made many
believe that the longer we sleep the healthier we are. In addition,
long sleep improves memory consolidation. Fact: All we need for
effective learning is well-structured sleep at the right time and of
the optimum length. Many individuals sleep less than 5 hours and wake
up refreshed. Many geniuses sleep little and practice catnaps. Long
sleep may correlate with disease. This is why mortality studies show
that those who sleep 7 hours live longer than 9-hour-sleepers. The best
formula for good sleep: listen to your body. Go to sleep when you are
sleepy and sleep as long as you need. When you catch a good rhythm without
an alarm clock, your sleep may ultimately last less but produce far
better results in learning. It is the natural healthy structure of sleep
cycles that makes for good learning (esp. in non-declarative problem
solving, creativity, procedural learning, etc.)
- Myth:
Alpha-waves are best for learning. Zillions of speed-learning programs
propose learning in a "relaxed state". Consequently, gazillions of dollars
are misinvested by customers seeking instant relief to their educational
pains. Fact: It is true that relaxed state is vital for learning.
"Relaxed" here means stress-free, distraction-free, and fatigue-free.
However, a red light should blink when you hear of fast learning through
inducing alpha states. Alpha waves are better known from cropping up
when you are about to fall asleep. They are better correlated with lack
of visual processing than with the absence of distracting stress. You
do not need "alpha-wave machinery" to enter the "relaxed state". You
can do far better by investing your time and money in ensuring good
peaceful environment for learning, as well as skills related to time-management,
conflict-resolution, and stress-management. Neurofeedback devices may
play a role in hard to crack stress cases. However, good health, peaceful
environment and loving family are your simple bets for the "relaxed
state"
- Myth: Memory
gets worse as we age. Aging universally affects all organs. 50%
of 80-year-olds show symptoms of Alzheimer's disease. Hence the overwhelming
belief that memory unavoidably gets rusty at an older age. Fact:
It is true we lose neurons with age. It is true that the risk of
Alzheimer's increases with age. However, a well-trained memory is quite
resilient and shows comparatively fewer functional signs of aging than
the joints, the heart, the vascular system, etc. Moreover, training
increases the scope of your knowledge, and paradoxically, your mental
abilities may actually increase well into a very advanced age
- Myth:
You can boost your learning with memory pills. Countless companies
try to market various drugs and supplements with claims of improved
memory. Fact: There are no memory pills out there (August 2003).
Many drugs and supplements indirectly help your memory by simply making
you healthier. Many substances can help the learning process itself
(e.g. small doses of caffeine, sugar, etc.), but these should not be
central to your concerns. It is like running a marathon. There are foods
and drugs that can help you run, but if you are a lousy runner, no magic
pill can make finish in less than 3 hours. Do not bank on pharmiracles.
A genius memory researcher Prof. Jim Tully believes that his CREB research
will ultimately lead to a memory pill. However, his memory pill is not
likely to specifically affect desired memories while leaving other memories
to inevitable forgetting. As such, each application of the pill will
likely produce a side effect of enhanced memory traces for all things
learned in the affected period. Neural network researchers know the
problem as stability-vs.-plasticity dilemma. Evolution solved
this problem in a way that will be hard to change. Admittedly though,
combination of a short-lasting memory enhancement with a sharply-focused
spaced repetition (as with SuperMemo) could indeed bring further enhancement
to learning
- Myth: Learning
by doing is the best. Everyone must have experienced the value of
learning by doing. This form of learning often leads to memories that
last for years. No wonder, some educators believe that learning by doing
should monopolize educational practice. Fact: Learning by doing
is very effective in terms of the quality of produced memories, but
it is also very expensive in expenditure of time, material, organization,
etc. The experience of a dead frog's leg coming to life upon touching
a wire may stay with one for life (perhaps as murderous nightmares resulting
from the guilt of killing). However, a single picture or mpeg
of the same experiment can be downloaded from the net in seconds and
retained for life with spaced repetition at the cost of 60-100 seconds.
This is incomparably cheaper than hunting for frogs in a pond. When
you learn to program your VCR, you do not try all functions listed in
the manual as this could take a lifetime. You skim the highlights and
practice only those clicks that are useful for you. We should practise
learning by doing only then when it pays. Naturally, in the area of
procedural learning (e.g. swimming, touch typing, playing instruments,
etc.), learning by doing is the right way to go. That comes from the
definition of procedural learning
- Myth: It is
possible to memorize Encyclopedia Britannica. Anecdotal evidence
points to historical and legendary figures able of incredible feats
of memory such as learning 56 languages by the age of 17, memorizing
100,000 hadiths, showing photographic memory lasting years, etc. No
wonder that it leads to the conviction that it is possible to memorize
Britannica word for word. It is supposed to only be the question of
the right talent or the right technique. Fact: A healthy, intelligent
and non-mutant mind shows a surprisingly constant learning rate. If
Britannica is presented as a set of well-formulated questions and answers,
it is easy to provide a rough estimate of the total time needed to memorize
it. If there are 44 million words in Britannica, we will generate 6-15
million cloze deletions, these will require 50-300 million repetitions
by the time of job's end (see spaced repetition theory), and that translates
to 25-700 years of work assuming 6 hours of unflagging daily effort.
All that assuming that the material is ready-to-memorize. Preparing
appropriate questions and answers may take 2-5 times more than the mere
memorization. If language fluency is set at 20,000 items (this is what
you need to pass TOEFL in flying colors or comfortably read Shakespeare),
the lifetime limit on learning languages around 50 might not be impossible
(assuming total dawn-to-dusk dedication to the learning task). Naturally,
those who claim fluency in 50 languages, are more likely to show an
arsenal of closer to 2000 words per language and still impress many
- Myth: Learning
while sleeping. An untold number of learning programs promises you
to save years of life by learning during sleep. Fact: It is possible
to store selected memories generated during sleep by: external stimuli,
dreams, hypnagogic and hypnopompic hallucinations (i.e. hallucinations
experienced while falling asleep and while waking up). However, it is
nearly impossible to harness this process into productive learning.
The volume of knowledge that can be gained during sleep is negligible.
Learning in sleep may be disruptive to sleep itself. Learning while
sleeping should not be confused with the natural process of memory consolidation
and optimization that occurs during sleep. This process occurs during
a complete sensory cut-off, i.e. there are no known methods of influencing
its course to the benefit of learning. Learning while sleeping is not
only a complete waste of time. It may simply be unhealthy
- Myth: High
fluency reflects high memory strength. Our daily observations
seem to indicate that if we recall things easily, if we show high
fluency, we are likely to remember things for long. Fact: Fluency
is not related to memory strength! The two-component model of long-term
memory shows that fluency is related to the memory variable called retrievability,
while the length of the period in which we can retain memories is related
to another variable called stability. These two variables are
independent. This means that we cannot derive memory stability from
the current fluency (retrievability). The misconception comes from the
fact that in traditional learning, i.e. learning that is not based on
spaced repetition, we tend to remember only memories that are relatively
easy to remember. Those memories will usually show high fluency (retrievability).
They will also last for long for reasons of importance, repetition,
emotional attachment, etc. No wonder that we tend to believe that high
fluency is correlated with memory strength. Users of SuperMemo can testify
that despite excellent fluency that follows a repetition, the actual
length of the interval in which we recall an item will rather depend
on the history of previous repetitions, i.e. we remember better those
items that have been repeated many times. See also: automaticity vs.
probability of forgetting
The list
of myths is by no means complete. I included only the most damaging distortions
of the truth, i.e. the ones that can affect even a well-informed person.
I did not include myths that are an offence to our intelligence. I did not
ponder over repressed memories, subliminal learning, psychic learning,
or remote viewing (unlike CIA). The list is simply too long.