The Acquisition of Memories

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Chapter 4

• The Acquisition of Memories

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Memory
The next three chapters of the textbook will be
focused on memory. What is memory? From a
cognitive psychologists perspective, memory
influences are operating anytime that information
is being stored or kept alive in some fashion
such that subsequent behaviour might be
influenced by that information. e.g., driving a
car, 14x12, capitol of Ohio, last nights
dinner This is clearly a much more general
definition of memory that the one we typically
use in our everyday discussions (episodic memory)
and, given this, there is much that we need to
discuss.
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Breakdown
In order to present all this information in an
organized manner, the textbook breaks down memory
in the following manner. Chapter 4 - The
Acquisition of Memories Chapter 5 -
Interconnections between Acquisition
Retrieval Chapter 6 - Memory Errors, Memory
Gaps Chapter 7 - Associative Theories of
Long-Term Memory Chapter 8 - Concepts and
Generic Knowledge I will generally follow this
structure in my lectures as well. Thus, this
week we will be focusing on the acquisition of
memories how information gets into our memory.
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Information Processing (Box Arrows)
As mentioned in the Chapter 1 lectures, the
invention of the computer had a major impact on
the way that cognitive psychologists thought
about mental events. Specifically, the notion of
information processing is very strong in many of
the early theories. That notion holds that the
purpose of cognitive mechanisms is the take the
information passed to them, process it in some
manner, then pass in along to the next cognitive
mechanism. Such theories are often depicted in
box arrow diagrams, and the early theories of
memory are no exception. So ...
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The Modal Model of Memory
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Early Analysis
Although not discussed in the text, there seem to
be very short- lived memory stores at the early
sensory analysis stage. These stores keep the
sensory input alive for slightly longer, thereby
making in easier to process environmental
inputs. As examples, the visual version of this
is called iconic memory it tends to keep visual
stimuli available for about 1 sec after it has
disappeared. The auditory version of this,
echoic memory, is more impressive keeping
auditory information alive for up to 5-10 seconds
after it is no longer being emitted (e.g., the
what? effect).
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Short versus Long-Term Memory
The omission of a discussion of early analysis
memory is due to the fact that many cognitive
psychologists view it as a simple perceptual
store with little in the way of active
processing of the information. Thus, cognitive
psychologists tend to focus on short and
long-term memory. Weve already discussed this
distinction to some extent but, again, the
notion is that we have two memory systems The
short-term memory system is one that keeps
information within easy reach for things we are
currently working on (desk), whereas long-term
memory is used to refer to the warehouse of
knowledge we have stored away (file cabinet).
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Evidence for this Distinction
Why should we accept this notion of two different
types of memory? Most of the evidence for it
comes from a task called free recall In the
free recall task, participants are given a list
of words to remember like tree, dirt, frog,
desk, pen, phone, text, staple, stream,
lamp Typically, these items are presented at a
rate of about 1/sec. Participants are then asked
to recall as many of the items as they can. A
critical analysis of this data examines the
probability of recalling an item as a function of
its serial position, where tree would be in
position 1, pen in 5, and lamp in 10.
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Serial Position Curve
Primacy Effect
Recency Effect
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The Story
As items are read off, they enter into working
memory. However, working memory is capacity
limited so, as more items are read off, the most
recent words bump the least recent out of
working memory thus, when the list ends, the
most recent items can be simply read out from
working memory the recency effect. Again, as
the words are read out, participants try to
remember them by silently repeating them to
themselves (which increases the likelihood of
them entering LTM). For the first item, it will
be repeated by itself for a while (tree
tree), then when the second item is read
(tree-dirt tree-dirt), then when the third is
read (tree-dirt-frog ). As this shows, early
items in the list should have a greater chance
of entering into LTM the primacy effect.
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Recency Effect Due to STM?
The evidence supporting the link between STM and
the recency effect come from studies that have
had either a blank or filled delay between the
last item on the list, and recall. Critically,
when subjects must do something in this delay
such as count backwards by threes, the recency
effect disappears just as it should if it is due
to working memory.
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Primacy Due to LTM?
Further evidence comes from studies that
manipulate exposure duration recall that the
capacity of working memory seems to be based on
number of items not time thus giving subjects
more time should benefit those parts of the
curve due to long-term memory, but have no
effect on that due to short-term memory
Slow presentation was 9 sec/item, the fast
presentation was 3 sec/item Sumby, 1963
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Summarizing Serial Position
Thus, based on evidence like that discussed,
researchers became convinced that there were two
distinct kinds of memory, one responsible for the
primacy effect (LTM), and the other responsible
for the recency effect (STM or working
memory). See further discussion of recency
effect in the text This, however, does not
necessarily mean that the box and arrows modal
model is correct in fact, more recently
researchers have begun to think of working memory
as not some storage place but, instead, as a
state of sorts. That is, working memory
may simply reflect those concepts in long-term
memory that are currently active choir analogy
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A Closer Look at Working Memory
As suggested, there is generally thought to be a
very close correspondence between working memory
and what we generally call thinking. Given
this, several individual differences studies have
been conducted to assess whether ones working
memory capacity is related to performance on
various tasks. for example, reading speed and
comprehension, reasoning In order to perform
such studies there needs to be some good measure
of peoples working memory capacity as
previously discussed, this typical involves a
digit span test but there is a potential
problem with that test chunking.
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Chunking
A famous study by Miller (1956) showed that
working memory could hold 7 plus or minus 2
chunks of information. To understand a
chunk, think of the following numbers 7 - 4
- 7 - 1 - 4 - 9 - 4 7 chunks 747 - 14 -
94 3 chunks 747 - 1494 2 chunks big
plane two years after Columbus 2 good
chunks! Thus, these 7 numbers can be chunked
in various ways a very good chunker discussed
in the text could remember number sequences as
long as 79 digits long! Ever see one of those
hypnotists? probably a chunker.
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The Dynamic Nature of Working Memory
The notion of chunking supports the idea that
working memory is a very dynamic form of memory,
not a simple storage place as suggested by the
modal model more like the choir idea. This has
lead some to also dislike using span tasks
to measure working memory, instead favouring
new more dynamic tasks that really tap the full
potential of it such as ...
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The Bias Towards Speech Sounds
Recall from Chapter 1 that one major component of
the working memory system is thought to be an
articulatory loop. We discussed some of the
evidence for this loop, and more is discussed in
Chapter 4. This fits with our subjective
impression that we often think in words. But is
that ALL there is to our thoughts?
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The Visuo-Spatial Scratch Pad
Imagine that I ask you to answer the following
questions How many windows are there on your
house? How high could I reach if I were sitting
on a camel? What object would be formed if you
did the following imagine a capitol d
rotated so the curved part was up, then
imagine a capitol j positioned directly under the
d. Clearly you are thinking to answer these
questions, but you are thinking in images, not in
words this suggests that working memory also
contains some sort of visuo-spatial scratch pad
which has been studied a little, but not that
much.
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Other Senses
We can take this a step further and ask things
like What would it feel like if warm honey
were slowly dripped on your back while you were
bent slightly forward. What would the echo of a
pig grunt sound like? What does an orange smell
like? All of these tasks are analogous to what
the articularity loop does, (1) create some
stimulus, (2) experience it as if it were
real. Clearly we are better at some of these
things that others (e.g., we clearly do words
better than smells) but the fact that we can do
them suggests we have slave systems for all these
tasks.
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The Central Executive
The role of the central executive in all this is
to activate the necessary systems then to
examine their results (whenever it is appropriate
to do so) and to output a response. This should
smack of a limited capacity response selector
and there does indeed seem to be a relation
between the two. Unfortunately, as sometimes
happens in any science, the camps investigating
the two issues (working memory versus divided
attention) have not yet tried to bridge the
gap to link these two seemingly related things,
and to test the predictions stemming from the
link.
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Summary of Sorts
The stated purpose of this chapter was to discuss
how things get into long-term memory we have
focused on working memory because it seems to be
the main path into long-term memory. Given
this, lets just re-emphasize the following
points. Working memory can be filled with
information from the real world (phone numbers)
or from long-term memory (windows in old
house) Only so much can be in working memory at
a time, when new stuff comes in, old stuff gets
booted out. Working memory is the place where
experiences can be repeated via a variety of
production loops may be critical for LTM.
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From Working Memory to LTM
The process by which information enters into
long-term memory is called consolidation. It is
thought that the main way consolidation occurs is
via working memory. That is, information that is
in working memory may be transferred to long-term
memory for future reference. One would think
that the recycling of information often
performed by working memory would aid this
transition as it allows a stimulus to be
experienced more often than it was
presented. Thus, the more a stimulus is
rehearsed, the higher the chance of it entering
long-term memory, right? However, the story is
not quite as simple as that.
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Maintenance Rehearsal
Craik Watkins (1973) performed an experiment
relevant to this notion they read subjects a
list of words, but subjects were instructed that
they only needed to remember the last word
that began with a B that is, the list would
terminate at some point, and subjects would then
be asked for the last B word.
For example basket, spoon, telephone, cup,
lamp, fish, hair, plant, lake, book, chair, foot,
baby, hill, tree last B word? After doing a
bunch of these, subjects, to their surprise, were
then asked to remember all the B words. Note
that some of the B words should have been
practiced more than others. Did this
extra practice help?
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Craik Watkins (1973) Results
As indicated by the graph to the left, the answer
appears to be no the extra
maintenance rehearsal had no effect on the
chances of the item entering LTM. Thus, simply
repeating something over and over will not get it
into your long-term store. So how do things get
into long- term memory then?
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Elaborative Rehearsal
If you really want to remember something, then
the best thing you can do is to think deeply
about it (course notes example). Specifically,
the new information needs to be attached to
information already in long-term memory, and
attached to any cues that you can think of that
might help you to retrieve that information
later (use of analogies and examples in
class). In fact, this deep processing is more
important even than your intention to learn
which, it turns out, is largely irrelevant. The
following conglomerate experiment makes both of
these points well.
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Experimental Design
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Results (composite)
While the depth variable strongly effects
later recall, the intent variable has seemingly
no effect whatsoever. Thus, if you want to
learn some new information, actively think about
it perhaps by organizing the information,
coming up with examples, etc
Depth of Processing
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So intent is irrelevant?
The previous results may have lead you to believe
that your intention to learn or not is irrelevant
to whether you will learn only the depth of
processing matters. This is true in the previous
study ONLY because participants were instructed
as to how to process the stimuli. In a more
natural setting, intent may indeed manner since
someone who is trying to learn some material may
be more likely to use a deeper form of processing
that someone who is not trying this assumes
they realize that processing items deeply is the
way to good subsequent memory (i.e., learning).
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What is it that Depth does?
When we say we have learned something, we mean
that we are able to talk about it (i.e., retrieve
the relevant information) after we have
experienced it. In this sense, learning is
about retrieval as much as it is about storage.
Thus, the enhanced learning caused by depth may
stem from a retrieval benefit, not a storage
benefit. The texts library indexing
example In fact, as stressed in the text, most
cognitive psychologists believe that the enhanced
learning associated with deep processing
comes about because deep processing encourages us
to form connections between the information
to-be-remembered and existing memory.
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Organizing and Forming Connections
The general notion, then, is that information is
better remembered if that information is
organized (i.e., if connections are formed
within the to-be-remembered stimuli) and if it
is associated with information already in memory
(i.e., connections are formed with existing
knowledge). There are a number of experiments
relevant to these claims Craik Tulving
(1975) She cooked the ________.
(chicken) The great bird swooped down and
carried off the struggling ________. (chicken)
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More Examples
Also, participants are much better at remembering
structured lists (e.g., gun - knife - sword -
chair - couch - table ) than they are at
remembering non-structured lists. In fact, even
if a structured list is scrambled such that
members of each category are not all presented
together participants will tend to re-organized
the material (a process called clustering)
when they recall it such that they recall the
items within a category together. This suggests
that humans have a natural tendency to organize
materials in ways that will help them to
remember. Thus, a great way to remember
information is to structure it in ways that allow
you to connect the pieces of information well.
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Understanding (the best structure)
The best structure comes from gaining a true
understanding of how the information should be
connected figuring out the principles or themes
that connect the information. For example The
procedure is actually quite simple. First you
arrange items into different groups. Of course,
one pile may be sufficient depending on how much
there is to do. If you have to go somewhere else
due to lack of facilities that is the next step
otherwise you are pretty well set. It is
important not to overdo things. That is, it is
better to do too few things at once than too
many. In the short run this may not seem
important but complications can easily arise. A
mistake can be expensive as well. At first, the
whole procedure will seem complicated.
Soon however it will become just another facet of
life. It is difficult to foresee any end to the
necessity for this task in the immediate future,
but then, one can never tell. After the
procedure is completed, one arranges the
materials into different groups again. Then they
can be put into their appropriate places.
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Relating this all to my teaching style
It is for all of these reasons that I make my
lectures notes available prior to classes, but
that I also make them somewhat skeletal (that is,
I do not provide all the info). In my view,
madly taking notes is a perfect example of a
shallow processing task leaving you to learn
on your own at some later time. In contrast, if
you come to class and think about what is being
said, and the examples and analogies I use help
you to connect the new material with existing
knowledge, then you have a better chance of
understanding the concepts the first time
through, and of remembering the concepts later.
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The Role of the Learner
Of course, anything I might do to help you
understand and structure the material is useless
if you do not actively engage in thinking. My
greatest worry is that giving out the class notes
will entice some students into not attending
classes thereby completely erasing any chance
of the deep processing I am trying to
encourage. Moreover, some students come to
class, but then snooze, or think about other
stuff, or talk to their friends, etc Again,
these students are wasting an opportunity to
learn something easily. The moral, good memory
happens when the learner engages in deep
processing of the to-be-learned material likely
because deep processing allows for better
subsequent retrieval.
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Chapter 4 Summary
We covered a fair amount in this chapter
including the modal model (short vs. long
term memory) evidence for the distinction
between short long-term memory a
fairly detailed discussion of short-term memory
including the choir notion of its relation
to long-term memory the importance of depth
of processing to subsequent memory depth as
helping retrieval via connections as opposed to
helping with acquisition per se. how
understanding maps onto all this