Mind Hacks™: Tips & Tools for Using Your Brain (44 page)

A 2,500-year-old memory trick shows how our memory for events may be based on our
ability to remember routes to get to places.

How many words do you think you could remember if given an arbitrary list and around
10 seconds per word in which to learn them? Knowing that my memory isn’t all that good, I
thought perhaps I could remember around 10. So I decided to use the method of loci to
remember 20 words, twice that number. I didn’t want to come up with my own list, because
it would be easier for me to remember, so I used the 20 most common words appearing in the
lyrics of the songwriter Tom Waits, as kindly provided by the excellent Tom Waits
Supplement (
http://www.tomwaitslibrary.com/lyrics-common.htm
) and shown in
Table 9-5
.

Perhaps you think 20 is too easy; feel free to use a longer list or give yourself less
time, if you’re so inclined. But 20 in 4 minutes seemed daunting enough for me. Starting
with “night” (131 mentions across Tom Waits’ entire discography) and finishing with “girl”
(40 mentions), I imagined something to do with each item at each point of the journey from
the front room of my house, where I was sitting, to my nearest subway station.

After mentally doing the journey and noting the items strewn along the way (a
“love” letter at the foot of the stairs, a “drink” of coffee at the café on the corner,
and so forth) and checking that I thought I’d remembered them all, my 4 minutes were up
and I pulled out my notebook and got my pen ready to write down the list of items.

Normally with things like this my mind goes blank as soon as the thing I’m supposed to
be remembering leaves my sight. But, using the method of loci, I was impressed with how
quick and easy it was to remember all the words. (Yeah, yeah, I know I’m supposed to know
that it works, but I still managed to impress myself.) I got every item right, and only
two out of order.

Try it yourself. It doesn’t have to be these words. It can be things, people,
numbers — anything. This is one of the tricks professional memory artists use to remember
lists of hundred, or even thousands, of things.

There are several reasons this method works to help aid your memory, but the main one
is the attaching of things to locations in space.

We know that the human brain has specialized mechanisms dedicated to remembering landmarks,
¹
and that (interestingly) this region and those nearby seem to be
responsible for giving humans and other animals a sense of where they are in space.
²
Brain imaging of people navigating through virtual environments has shown
that even if we don’t consciously recognize something as a landmark it still triggers a
response in this specialized part of the brain.

This part of the brain, the
hippocampus
and nearby
nuclei
, is also known to be absolutely crucial for storing our
memory for events. Psychologists call this kind of memory
episodic
memory
, to distinguish it from memory for facts or memories of how to do
things. People with hippocampal damage (like the hero of the film
Memento
(
http://www.imdb.com/title/tt0209144
),
for example) aren’t able to store new episodic memories, although they can
retain memories for episodes that they stored before their injury and they can learn new
facts (with lots of effort) and skills.

So we know that this same part of the brain, the hippocampus, seems to be crucial both
for recording events and for helping us understand where we are in space. Evidence that
this first function may have evolved from the second has recently been published.
³
It was found that the expectations and intentions an animal has affect how
the hippocampus encodes memory for locations in the hippocampus. This encoding of context
for locations at different times may have laid the foundations for the encoding of context
in time for other memories. From this may have developed the memory for events, that
ability to mentally time travel, which makes up what most of us think of as our
memories.

You can see this landmark-specialized processing at work when we give and follow
directions. If you are following directions and go past something that’s an obvious
landmark and your directions don’t specify it, you know something’s wrong. Interestingly
there is also evidence from brain imaging that supports the well-known fact that men and
women tend to navigate in a different manner; women tend to rely more on landmarks alone,
whereas men rely more on absolute spatial position (the geometry of the situation) in
combination with landmarks.
⁴
The information architect Christina Wodtke has observed that “On the Web,
everyone’s a woman,” because there is no consistent spatial geometry; we are
all
forced to rely on landmarks.
⁵

Our regular experience of the world is first person, but in some situations, we see
ourselves from an external perspective. These out-of-body experiences may even have a
neurological basis.

Remember back to when you were last lying down reading something: perhaps it was on
holiday at the beach, in a local park, or just on the couch at home. Try and fix that
image in your mind.

Now, notice where your “mind’s eye” is. Are you looking at yourself from an external
point of view — much like someone wandering by might have seen you — or are you remembering
yourself looking out through your own eyes as you are while reading this book right
now?

The majority of people remember a scene like this from a seemingly disembodied
third-person perspective, despite originally having experienced it from a first-person
point of view.

The first study to explore this effect in detail was published in 1983 by Nigro and Neisser.
¹
They made the link between the likelihood of recalling a memory as either a
first-person or third-person image and emotions and discovered that asking someone to
focus on their feelings at the time of the event was more likely to result in a
first-person memory. The example in the
preceding
In Action
section focused on a situation
and was probably a fairly neutral emotional experience, so is likely to produce a
third-person memory in most people.

Although this is a common experience when remembering the past, the majority of people
do not have out-of-body experiences in the present. People who have recounted out-of-body
experiences have sometimes been suspected of being overimaginative or worse, but such
experiences are a well-known phenomenon in certain types of epilepsy and with specific
forms of brain injury. This does not mean that people who experience out-of-body states
necessarily have epilepsy or brain injury, but these sorts of conditions suggest that
normal, but usually hidden, aspects of brain function may be involved in producing such
experiences.

A study by Blanke and colleagues
²
examined five neurological patients who had frequent out-of-body
experiences. On one occasion, a surgeon managed to reliably induce such an experience by
electrically stimulating the cortex of a patient during brain surgery. When the surgeon
stimulated the
tempero-parietal junction
(the area of the brain where
the temporal and parietal lobes meet
[
Tour the Cortex and the Four Lobes
]
), the patient reported that
she felt an instantaneous sensation of floating near the ceiling and experienced the
operating theater as if she were looking down on it, “seeing” the top of the doctors’
heads and herself on the operating table. Ceasing the stimulation “returned” the patient
to her body, and resuming it caused her to feel disembodied once more.

Brain imaging studies have shown that the tempero-parietal junction is activated in
situations that involve calculating point of view from an egocentric perspective and
mentally switching between views to understand a scene (for example, mentally working out
a good place to stand to get the best view of a football game). With this in mind, it is
perhaps not so surprising that unusual activity in this area might cause feelings of being
detached from the body.

Although it is too early to say for sure, it seems likely that when we recall images
that appear in the third-person perspective, the tempero-parietal junction is being
recruited to help create this image. The previous exercise demonstrates that, in the
context of memory, we all have the ability to experience the out-of-body state. It also
suggests that there may be a sound neurological basis for such experiences and that
healthy people who report out-of-body experiences are being less fanciful than some
skeptics presume.

— Vaughan Bell

On the edge of sleep, you may enter hypnagogia, a state of freewheeling thoughts and
sometimes hallucinations.

Although there is no guaranteed technique to extend or intensify the hypnagogic state,
sometimes it can be enough to simply make a conscious effort to be aware of any changes in
consciousness as you relax and drop off, if practiced regularly. Trying to visualize or
imagine moving objects and scenes, or passively noting any visual phenomena during this
period might allow you to notice any changes that take place. Extended periods of light
sleep seem more likely to produce noticeable hypnagogia, so being very tired may mean you
enter deep sleep too quickly. For this reason, afternoon dozing works well for
some.

Some experimenters have tried to extend or induce hypnagogia by using light
arousal techniques to prevent a quick transition into deep sleep. A microphone and speaker
were used in one study to feed the sound of breathing back to the sleeper. Another method
is the use of “repeat alarm clocks” (like the snooze function on many modern alarm
clocks) — on entering sleep, subjects are required to try and maintain enough awareness to
press a key every 5 minutes; otherwise, a soft alarm sounds and rouses them.

Try this yourself on public transport. Because of the low background noise and
occasional external prompting, if you manage to fall asleep, dozing on buses and trains
can often lead to striking hypnagogic states. In spite of this, this is not always the
most practical technique, as you can sometimes end up having to explore more than your own
consciousness if you miss your stop.

Very little research has been done on brain function during the hypnagogic state,
partly because conducting psychology experiments with semiconscious people is difficult at
the best of times and partly because many of the neuroimaging technologies are not very
soporific. fMRI
[
Functional Magnetic Resonance Imaging: The State of the Art
]
scanning tends to be
noisy and PET scanning
[
Positron Emission Tomography: Measuring Activity Indirectly with PET
]
often involves having
a drip inserted into a vein to inject radioactive tracer into the bloodstream — hardly the
most relaxing of experiences. As a result, most of the research has been done with EEG
(electroencephalogram) readings
[
Electroencephalogram: Getting the Big Picture with EEGs
]
that involve using
small scalp electrodes to read electrical activity from the brain.

Hideki Tanaka and colleagues
¹
used EEG during sleep onset and discovered that the brain does not decrease
its activity evenly across all areas when entering sleep. A form of alpha wave activity
(electrical signals in the frequency range of 8–12 Hz that are linked to relaxed states)
spreads from the front of the brain to the other areas before fading away. The frontal
cortex is associated with attention (among other things), and it may be that the
hypnagogic state results from the progressive defocusing of attention. This could cause a
reduction in normal perception filtering, resulting in loosely connected thoughts and
unusual experiences.

Some scientists have argued that the hypnagogic state is not necessarily sleep-related
and may be the result of a reduction in meaningful perceptual information, perhaps leading
to defocused attention or other similar effects. A study published in 2002
²
aimed to test this by comparing hypnagogic states with a condition in which
awake participants were fed unstructured sensory information in the form of white noise
and diffuse white light. The researchers used EEG recordings and found that, although
participants in both conditions reported unusual visual experiences, the pattern of brain
activation were quite different, suggesting that hypnagogia is more than just the result
of relaxation and lack of structured sensory input.

One problem with recording electrical activity from the scalp is that activity from
structures that lie deep in the brain may not be detected. This means we could be missing
important information when it comes to understanding what happens as we slip from
consciousness into sleep, and even back again into wakefulness (known as the
hypnopompic state
) — particularly as deep structures (such as the
brain stem, pons, thalamus, and hypothalamus) are known to be crucial in initiating and
regulating sleep.

An ingenious study published in
Science
did manage to investigate
the role of some of the deeper brain structures in hypnagogia,
³
specifically the medial temporal lobes, which are particularly linked to
memory function. The researchers asked five patients who had suffered medial temporal lobe
damage to play several hours of Tetris. Damage to this area of the brain often causes
amnesia, and the patients in this study had little conscious memory for more than a few
minutes at a time. On one evening, some hours after their last game, the players were
woken up just as they started to doze and were asked for their experiences. Although they
had no conscious memory of playing the game, all of the patients mentioned images of
falling, rotating Tetris blocks. This has given us some strong evidence that the
hypnagogic state may be due (at least in part) to unconscious memories appearing as
unusual hypnagogic experiences.

Many authors and artists have been fascinated by this state and have tried to
extend or use it to explore ideas or gain inspiration. To name a couple, Robert Louis
Stevenson’s
The Strange Case of Dr. Jekyll and Mr. Hyde
and many of
Paul Klee’s paintings were reportedly inspired by hypnagogic experiences.

— Vaughan Bell