Brain Rules (Updated and Expanded)

Remembrance of Things Past
, talked
freely 100 years ago about smells and their ability to elicit long-lost
memories. Why? Remember, smell neurons gain VIP access to the
amygdala.
Smell has the unique advantage of being able to boost learning directly,
without being paired with another sense. That’s because it is an ancient
sense, not fully integrated with the rest of the brain’s sensory circuitry but
instead closely wired to the emotional learning centers of the brain. In the
typical experiment testing the effect of smell on remembering, two groups
of people might be assigned to see a movie together and then told to report
to the lab for a memory test. The control group takes the test in a plain
room. The experimental group takes the test in a room smelling of popcorn.
The second group blows away the first group in terms of number of events
recalled, accuracy of events recalled, specific details, and so on. In some
cases, they can accurately retrieve twice as many memories as the controls.
However, this is true for only certain types of memory. Odors appear to
do their finest work when subjects are asked to retrieve the emotional
details of a memory—as our medical student experienced—or to retrieve
autobiographical memories. You get the best results if the smells are
congruent. A movie test in which the smell of gasoline is pumped into the
experimental room does not yield the same positive results as the smell of
popcorn does.
Odors are not so good at retrieving declarative memory. Smell boosts
declarative scores in only a couple of scenarios. It works if you’re
emotionally aroused—usually, that means mildly stressed—before the
experiment begins. For some reason, showing a film of young Australian
aboriginal males being circumcised is a favorite way to do this. And it
works if you’re asleep. Researchers used a version of a delightful card game
my sons and I play on a regular basis. We use a deck of cards we purchased
at a museum, resplendent with 26 pairs of animals. We turn all of the cards
facedown, then start selecting two cards to find matches. It is a test of
declarative memory. The one with the most correct pairs wins the game. In

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the experiment, the control groups played the game normally. But the
experimental groups didn’t. They played the game in the presence of rose
scent. Then everybody went to bed. The control groups slept unperturbed.
Soon after the snoring began in the experimental groups, however, the
researchers filled their rooms with the same rose scent. Upon awakening,
the subjects were tested on their knowledge of where the matches had been
discovered the previous day. The control group answered correctly 86
percent of the time. Those exposed and reexposed to the scent answered
correctly 97 percent of the time. Brain imaging experiments showed the
direct involvement of the hippocampus, that region of the brain deeply
involved in memory. Smell, it appeared, enhanced recall during the offline
brain processing that normally occurs during sleep.
Smell aside, there is no question that multiple cues, dished up via
different senses, enhance learning. They speed up responses, increase
accuracy, improve stimulation detection, and enrich encoding at the
moment of learning.
More ideas
Multimedia presentations
Over the decades, Mayer has isolated a number of rules for multimedia
presentations, linking what we know about working memory with his own
empirical findings on how multimedia exposure affects human learning.
Here are five of them, as he summarized in his book 
Multimedia Learning
,
useful for anyone giving a lecture, teaching a class, or creating a business
presentation.