Memory 261
associated with making more money. But researchers found that by pairing low-
er-value memories with a characteristic sound and then playing that sound back
to the sleeping participants, those low-value items were better recalled—even bet-
ter than when those same sound cues were played during waking periods. Sleep
is necessary to rehearse and consolidate the things we want to remember from our
waking day.
- Can you learn while asleep? That has long been a hope of many a college student
who has played a recording of lectures while sleeping, but it has never worked. It
turns out that the mistake was not in trying to learn while asleep but trying to learn
something new while asleep. Participants in one study learned how to play two pre-
viously unfamiliar tunes. They were then allowed to take a 90-minute nap, during
which researchers (using information from an EEG) presented one of the tunes they
had practiced during slow-wave sleep, a stage of sleep associated with memory
consolidation. Sure enough, the tune presented during sleep was remembered sig-
nificantly better than the one that was not presented (Antony et al., 2012).
- Sleep deprivation severely interferes with the functioning of the hippocampus, the part
of the brain that is vital for forming new memories (Basner et al., 2013; Poe et al.,
2010). to Learning Objective 2.11. People who live a lifestyle that is typically
sleep deprived—such as college students, doctors, nurses, and so on—are doing
their memories no favors.
- Sleep also helps prevent forgetting. We already know that interference causes forget-
ting, and it should come as no surprise that sleep reduces the amount of interference.
But researchers have also found that sleep may protect new memories by inhibiting
the workings of the neurotransmitter dopamine, a chemical in certain areas of the
brain that is involved in forgetting (Berry et al., 2015). Remember to sleep, because we
sleep to remember!
Exercise: It turns out that even brief exercise can be good for your memory
(Petersen, 2015). Researchers had people 50 to 85 years old look at pleasant images,
such as photos of animals and nature scenes (Segal et al., 2012). Some of these par-
ticipants also had memory deficits. Immediately after viewing the pictures, half of the
participants rode a stationary exercise bicycle for 6 minutes. One hour later all, partic-
ipants were given a surprise recall test on the previously viewed pictures. Regardless
of memory impairment, the participants who exercised showed substantially improved
memory when compared to those who did not exercise. The possible explanation for
this improved memory may lie in the extra norepinephrine released during exercise. Nor-
epinephrine, a neurotransmitter found in the brain, plays a strong role in the formation
of memories.
Diet: How many times have you heard that fish is brain food? Well, it turns out that
it probably is brain food, at least when it comes to improving memory. Fish, particularly
salmon, bluefin or albacore tuna, and swordfish, have high levels of an omega-3 fatty acid
called DHA (docosahexaenoic acid). In a recent study, researchers fed a high-DHA diet to
lab animals and found that, when compared to lab animals not fed the special diet, there
was a 30 percent increase in DHA levels in the hippocampus of the brain (Connor et al.,
2012). DHA appears to help memory cells communicate with each other better, resulting in
improved memory function. Other foods high in DHA include ground flax seeds, walnuts,
grass-fed beef, and soybeans, and of course there are numerous fish oil supplements on
the market.
Questions for Further Discussion
- Why do you think learning something new while asleep does not work?
- What might be the dangers in using supplements to get DHA in your diet?
