Mind Hacks™: Tips & Tools for Using Your Brain (42 page)

Here is one way of creating memories of things that you haven’t actually
experienced.

Let’s show false memory construction with a couple of word lists. First wrap
your eyes around the words in
Table 9-3
,
read them out loud once, then close the book and try to list all the words you saw.

Do the same with the next set listed in
Table 9-4
: read the words aloud, then close
the book and make a list.

Don’t worry about the words you didn’t get. But did your lists include either “needle”
or “sleep”? If so, you should know that those two words were phantoms in your mind:
They’re not in either list! This is the
Deese/ Roediger/McDermott
paradigm
, or DRM,
¹
and highlights how the fallibility of memory is not limited to the absence
of information but includes outright fabrications. Experts believe that this doesn’t
represent glitches in the system but an outcome of the healthy memory system — built as well
as needs be.

One point ought to be noted: when this technique is used, subjects are asked not to
guess and typically will afterward state that they reported the “critical lure” (the lure
is one of the words we asked whether you’d seen just now, but which wasn’t in either list,
e.g., “needle”) not because they had a hunch that it could be there, but because they
actually remember seeing it.
In other words, there is a reported subjective experience of the word that
wasn’t there. This experience seems strong enough to produce better memory for the
critical lures (which were never seen) than for the real items when retested two days
later!

This technique can also be used to test recognition memory, but we are showcasing
recall here due to the effect being so surprising, and recognition being already described
[
Fake Familiarity
]
.

The exact causes of this phenomenon are still up for debate. Obviously, the similarity
of the listed items to the critical lure is essential — in the parlance, these words are
associates of the lure
. A popular argument is that items are
represented in the mind in a relational network, each neighbored by its closest
associates: when an item is flagged, it sends activation to surrounding nodes, and with
the DRM all the critical lure’s neighbors are being flagged, setting it off as surely as
you could burn down a building by setting fires all around it. Sure enough, the more
associates you show, the more the phantom pops out.

What is critical to understand is that an internal representation is being elicited,
without the express intention of the subject, and later being confused with an external
event. In this sense it is similar to, though distinct from, the memory error described in
Keep Your Sources Straight (if You Can)
.

It’s clear that an idea can be lodged in our heads by using backdoor techniques. A
thought can be created in our minds with just inference and association, rather than by
being explicitly stated.

The DRM reveals how we may bypass rational channels and achieve this end directly in
memory by exploiting the brain’s tendency to elicit ideas and concepts as a consequence of
exposure to its associates. It suggests that the words “injection,” “thimble,” and
“thread” may spark a thought of “needle” due, not to a leap of logic, but to the dance of
association within mental networks.

This hack also serves as a circumscribed example of truly false memory. As told in
other hacks
[
Fake Familiarity
and
Keep Your Sources Straight (if You Can)
]
, events can be
falsely familiar, or wrongly identified as to their source — even to the extent of confusing
imagination with true past events. Now we see that we can produce information that really
wasn’t there at all. In addition, studies show that totally false but plausible events can
be inserted into people’s diaries and then accepted as a true event.
^2
,
3
We also
know that people presented with a visual scene (such as a photograph) will often remember
more of the scene than was actually presented; they fill in the scene with what makes
sense to be there. It has been suggested that this phenomenon is a consequence of
automatic activation of what is typically associated with this scene — very similar to the
DRM situation about which we’ve been talking. So while we’ve suggested that memory may be
somewhat constructed
[
Fake Familiarity
]
, these are examples in which memory is totally constructed, providing it
fits into the scripts and representations we have of our lives.

Accurate memory is critical when it forms the basis of a criminal accusation. We
discussed eyewitness memory
[
Fake Familiarity
]
before, but we could also consider recovered memories, particularly those
that involve alleged abuse.
²
Organizations have arisen to highlight how memory slips, such as filling in
details that feel as though they could mesh with the situation or mistaking an imagined
event for a real event, can lead to nonexperienced events seeming real. However, recent
research demonstrates that we can direct ourselves to forget certain events, under the
influence of frontally situated brain control systems (systems under voluntary
control) — that is, given a list of words, you can say to yourself “forget these words” and
find those words harder to recall in the future.
⁴
Given this, the idea that troubling events inevitably lead to strong and
present memories isn’t necessarily true, and it seems likely that recovered memories will
need to be assessed on their individual basis and content.

The view of the memory system that brain and behavioral sciences have unlocked
is one of distributed pattern completion. We ought to reject any notion of a
veridical
memory system (a memory system of statements
corresponding exactly with a truthful reality). The brain doesn’t favor discrete storage
of information; there isn’t a dusty file cabinet filled with DAT tapes stuffed with video
and audio files and lists of facts.

Instead, memories are represented in the brain as networks of related features.
Features that activate together cohere into a seamless, single, conscious memory. New
memories are new associations in the same networks. The mechanisms that contribute to this
coherence — the conscious experience of memory — are likely to be an exciting frontier in the
years to come, and we hope to see neuroscientific advances combine with refinements of
philosophical positions on the concepts of memory: from mental time travel (experiencing
the past) to ways of knowing.

Memory may be constructed, but it works and indeed seems fairly optimal for many of
our needs. It may be nonveridical — forget about any analogy of cameras rolling in our
heads — but its fidelity is good enough that our past is maintained as a largely unbroken
narrative, allowing us to be seated in an autobiographical identity.

Perhaps more important, the system is “good enough” to map the broad strokes of our
realities: memory performs the functions we need it to. For example, our memory mechanisms
mean we’re particularly good at remembering the remarkable in our surroundings, and
associated concepts come easily to mind. These are useful in real life. In general, it’s
handy that the concepts “bed” and “sheet” call the associated idea of “sleep” to mind — it’s
only in contrived list-learning situations, such as in the previous
In Action
section, in which we’d label that as a bad thing.

— Alex Fradera

When you learn something, you tend to store context as well. Sometimes this is a good
thing, but it can mean your memories don’t lend themselves to being recalled in different
circumstances.

Here’s an example of how the automatic encoding of context affects learning — in this
case, skill learning (skills are memories too). It’s called the
contextual
interference effect
, and it goes like this: practicing a collection of skills
in a random order is better than practicing them in runs.

So, for example, if you are learning Japanese, writing each character of the hiragana
(one of the three alphabets used in Japanese) is a separate motor skill. So it might be
better to practice your hiragana by writing all of them out together, rather than copying
out a hundred copies of one character, then a hundred copies of the next, and so on. You
learn slower this way, but you remember better.

Ste-Marie et al. used this technique when teaching grade two students handwriting,
practicing writing the letters
h
,
a
, and
y
.
¹
After writing each letter only 24 times, the students who practiced the
letters in a mixed-up fashion had better handwriting (i.e., better motor memories) than
the students who practiced in blocks, as soon as the very next day. You can acquire new
skills more effectively even after this short a time.

Even better, skills you have learned like this transfer better to new situations. If
you learn by repeating the same skill again and again, you’re going to learn it in the
context of repetition rather than how to do it one-off. Practicing with a series of
one-offs means you learn in many different contexts, and the memorized skill is more
sharply defined. It’s easier to recall and apply to a new context because it isn’t
interwoven as tightly with the learned context.

Most of the research on the contextual interference effect has involved simple motor
memories — these are skill memories, the kind you use in throwing Frisbees, juggling, or
swinging a golf club.

The effect is generally found only for skills that require significantly
different movements from each other. So, for example, you see a contextual interference
effect if you mix practice of throwing underarm and overarm, but not if you mix practice
of throwing a ball underarm exactly 2.7 meters and practice of throwing a ball underarm
exactly 3.2 meters. The skills in the first example use the muscles in different
combinations and with different relative timings. Separate motor memories are created for
the movements. In the second example, the two skills are just parameter-adjusted versions
of the same motor memory.

The contextual interference effect works only if you have some degree of experience in
the skills you’re practicing. To run into a contextual interference effect, the rough
framework of the motor memory must already be established. For example, when you first
start learning the Japanese alphabet, you don’t even have a skill you can practice — you
draw each character very deliberately (and badly!) and do it differently each time. Later,
when you’ve learned the rough shape of the character and are beginning to produce it
automatically, the rate at which you can improve the skill becomes open to the contextual
interference effect.

One possible cause of the contextual interference effect is that interleaving the
practicing of different skills requires concentration. It’s certainly true that mixed
practice is less boring, and we tend to remember less boring things more easily. But this
also begs a question: interleaved learning may be better because it prevents boredom, but
why does monotony bore us in the first place? Maybe boredom is the mechanism our brain
uses to make us provide it a sufficient variety of input for optimal learning!

But the main cause of the effect is that random-order learning softens the brain’s
normal tendency to encode context along with the core memory. Usually this is a good
thing — like when you are trying to recall where you first heard a song, met a person, or
who wrote a book you once read — but it can prevent us forming sharp edges on our memories
and reduce our ability to recall and use them in different situations.