As each of us goes
through life, we remember a little and forget a lot. The stockpile of what we
remember contributes greatly to define us and our place in the world. Thus, it
is important to remember and optimize the processes that make that possible.
People who compete in
memory contests (“memory athletes”) have long known the value of associational
cues (see my Memory Power 101 book).
Neuroscientists have known for a long time about memory consolidation
(converting short-term memory to long-term form) and the value of associational
cues. But now, important new understanding is arising from a research lab at
Northwestern that links cueing to “re-consolidation” and reveals new
possibilities for optimizing long-term memory formation.
The underlying research approach is based on such
well-established memory principles as:
When information is first acquired, it is tagged
for its potential importance or value.
Such tagging is influenced by multiple factors
such as repetition, attention, emotion, or purpose.
Valuable memories get preferentially rehearsed,
either through conscious will or by covert (implicit) brain processes.
Rehearsal episodes reactive the memory and
enhance long-term remembering because each re-consolidation episode builds on
prior ones and strengthens the neural circuits that store the memory.
Effectiveness of recall during rehearsal is
promoted by use of relevant cues, that is, information that was associated with
the original learning material.
Such cues are effective, even when delivered
The study involved 60
people in their early 20s, screened for good memory ability. 
All subjects participated in a four-hour learning period beginning in late
morning. The learning consisted of 72 images placed in specific locations on a
tile-like screen and presented one at a time. As each image appeared a
corresponding sound was associated, intended to serve as a learning cue. For
example, a dog picture would be associated with barking, cat with meow sound,
etc. To create a value bias, each image had a superimposed number representing
how important it was to remember this item and its location upon later testing.
Subjects were given financial reward for how well they remembered, and thus
remembering high-value images was a priority. Half of the images had high value
assignments, while the rest had low values.
Subjects were assigned to four groups:
Groups 1 and 2 were tested to see how well they
could remember where each object had appeared during the learning phase. They
then took a 90 min nap while their EEGs were recorded. Half of these subjects
heard white noise while the other have was presented the original sound cues of
low-value images during non-REM sleep at a level that did not cause awakening. At
the end of the nap, recall was again tested.
procedure in two other groups was similar except that these subjects did not
nap. One of these groups watched a movie during the 90 minutes after the
learning session, while the other group listed to the low-value sound cues
while performing a working memory task.
Not surprisingly, the
studies revealed that high-value images were remembered better, irrespective of
whether or not a nap was taken. The practical point is that we remember better
the things we value and find to have positive reward value. This reminds me of
the sage saying that T. Boone Pickens repeated from his basketball coach, who told
players after each game: “Don’t dwell on your mistakes. Think about what you
did right and do more of that!”
In the study, half of the
low-value associations were rescued by cueing during wakefulness and all of
them were rescued by cueing during sleep, even though only half of the images
were cued. Notably, the best effects occurred during the deepest stage of
sleep. No explanation was given to explain the sleep benefit, but I suspect it
is because the sleeping brain is not distracting itself with irrelevant thoughts.
This is consistent with the finding that low-value memories were not rescued
well during REM sleep, when the brain is busily engaged in dreaming. The
REM-sleep finding is at variance with other studies that reported a memory
consolidating benefit of REM sleep. Apparently, the test conditions make a
difference and more research is needed here.
were preferentially forgotten in the group that was not allowed to nap. This
likely signifies that a brain busily engaged with other thoughts is less able
to selectively consolidate memories, and only high-value items are likely to
survive. This accords with the long-held theory that distractions and
multi-tasking interfere with memory consolidation.
In summary, memory
optimization would seem to require one to:
1.Create associations that can serve as memory
2.Place a high value on the cues and their
present the cues and replay the initial information. When awake, present the
cues in self-test mode. When asleep, even better results would obtain if cues
were presented at a level that does not cause awakening during the early night
sleep when sleep is deepest and there is little dreaming.
1. Antony, J. W, Gobel, E. W.,
O’Hare, J., K., Reber, P. J., and Paller, K. A. (2012). Cued memory
reactivation during sleep influences skill learning. Nat. Neurosci. 15:
1114:1116. Rudoy, J. D., Voss, J. L., Westerberg, C. E., Paller, K. A. (2009).
Strengthening individual memories by reactivating them during sleep. Science.
2. Oudiette, D., Antony, J. W., Creery, J. D., and Paller, K. A. (2013) The role
of memory reactivation during wakefulness and sleep in determining which memories
endure. J. Neurosci. 33(15): 6672-6678.
Don't forget to check my memory e-book, Better Grades, Less Effort,