Human Memory
Memory
Forgetting Imagination inflation
Encoding
Interference theory Amnesia
Retrieval
Retroactive interference Mood
Retention
Proactive interference Self-referencing
Mnemonic devices False memories Primacy effect
Short term
Procedural/Episodic/Semantic memory
Working memory Repression Misinformation effect
Long term memory Suppression Elaborate rehearsal
Encoding failure
Source confusion Recency effect
Retrieval failure
Retrieval cues Serial position effect
• Memory refers to the mental processes that enable us
to acquire, retain, and retrieve information.
• There are three main process of memory.
• Encoding refers to the process of transforming
information into a form that can be entered and
retained by the memory system.
• Storage is the process of retaining information in
memory so that it can be used at a later time.
• Retrieval involves recovering the stored information so
that we are consciously aware of it.
• The stage model of memory states that memory
involves three stages: sensory memory, short-term or
working memory, and long-term memory.
Stage Model of Memory
• Sensory memory registers information from the environment
and holds it for a very brief period of time.
• An important function of sensory memory is to very briefly
store sensory impressions so that they overlap with one
another.
• Memory researchers believe there is a separate sensory
memory for each sense; however, your auditory sensory
memory holds sound information a little longer.
• Short term or working memory is the “workshop” of
consciousness, and provides temporary storage for
information that is currently being used in some cognitive
activity.
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Although information in short-term memory lasts longer than information in sensory memory, the
duration is still very short.
Information can be retained in short-term memory through the process of rehearsal; maintenance
rehearsal occurs when the information is repeated.
Visual sensory memory is one type of sensory memory. Visual sensory memory is also known as
iconic memory. Iconic memory was first studied by the psychologist George Sperling (1960).
Auditory sensory memory is known as echoic memory. In contrast to iconic memories, which decay
very rapidly, echoic memories can last as long as 4 seconds (Cowan, Lichty, & Grove, 1990).
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This is convenient as it allows you—among other things—to remember the words that you said at
the beginning of a long sentence when you get to the end of it, and to take notes on your
psychology professor’s most recent statement even after he or she has finished saying it.
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In some people, iconic or echoic memory seems to last longer than usual. For visual images, this
phenomenon is known as eidetic imagery (or “photographic memory”).
Information is encoded in short term memory so that it may be retrieved later.
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When short-term memory is filled to capacity, new information sometimes displaces currently held
information, through the process of maintenance.
Chunking is a method implemented to increase the amount of information that is stored in shortterm memory.
When you are presented with a sequence of information that you must retain, chunking, or
grouping related items together into a single unit, is beneficial.
The cognitive psychologist, Richard Cowan, disagreed with the findings of George Miller and
challenged the 7+ or – 2 theory. Cowan suggested that people automatically chunk stimuli to help
them remember.
• The phonological loop is one of three components of
working memory and is specialized for verbal material.
The second component of working memory is the
visuospatial sketchpad and is specialized for spatial or
visual material, i.e. remembering the layout of a room
or a town.
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• The central executive is the third component of
working memory which controls attention, integrates
information, and manages the activities of the
phonological loop and the visuospatial sketchpad.
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• The central executive also initiates retrieval and
decision processes and integrates information coming
into the system.
Encoding and Retention Strategies
• An effective encoding strategy is elaborative rehearsal. Elaborative
rehearsal is making a story to enhance memory.
• Elaborative rehearsal leads to better retention. Applying
information to yourself called the self-reference effect and the use
of visual imagery both enhance encoding.
• One way to prevent the decay of information from short-term
memory is to use working memory to rehearse it.
• Maintenance rehearsal is the process of repeating information
mentally or out loud with the goal of keeping it in memory. We
engage in maintenance rehearsal to keep a something that we want
to remember (e.g., a person’s name, e-mail address, or phone
number) in mind long enough to write it down, use it, or potentially
transfer it to long-term memory.
Long Term Memory
• Long term memory refers to the storage of information over extended
periods of time. The amount of information that can be held in long-term
memory is limitless.
• There are three major categories of information stored in long-term
memory; procedural, episodic, and semantic.
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• Procedural memory refers to the long-term memory of how to
perform different skills, operations, and actions.
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• Episodic memory refers to your long-term memory of specific
events or episodes, including the time and place that they occurred.
• Semantic memory is general knowledge that includes facts, names,
definitions, concepts, and ideas.
• Two dimensions of long term memory are explicit
memory, memory with awareness, and implicit
memory, memory without awareness.
• Explicit memory includes episodic memory and
semantic memory while implicit memory includes
procedural memory, priming, and learning through
classical conditioning.
• Priming, are changes in behavior as a result of
experiences that have happened frequently or
recently.
• Priming refers both to the activation of knowledge
(e.g., we can prime the concept of “kindness” by
presenting people with words related to kindness)
and to the influence of that activation on behavior
(people who are primed with the concept of
kindness may act more kindly).
• Explicit memory is assessed using tools in
which the individual being tested must
consciously attempt to remember the
information.
• A recall memory test is a measure of explicit
memory that involves bringing from the
memory information that has been previously
been remembered.
• Recall provides clues, or cues that enable us to
generate previously remembered information.
• Free recall is a measure of memory with no
prompts or clues.
• One measure of the influence of priming on
implicit memory is the word fragment test, in
which a person is asked to fill in missing letters
to make words.
• _ib_a_y
• _h_s__i_n
• _o_k
• _h_is_
• Cued recall includes a retrieval cue in the request for
memory….fill-in the blank questions use cued recall.
• Recognition memory test is a measure of explicit
memory that involves determining whether
information has been seen or learned
before…multiple-choice tests, for example.
• Recall is more difficult than recognition…essay tests
require recall and recognition.
• Essay questions require recall and recognition…in
recall, you must first generate an answer and then
determine whether it seems to be the correct
one…during recognition, you must determine which
item from a list seems most correct.
• Recall and recognition memory measures tend to be
correlated. Students who do better on a multiple-choice
exam will also, by and large, do better on an essay exam
• A third way of measuring memory is known as relearning.
• Measures of relearning (or savings) assess how much more
quickly information is processed or learned when it is
studied again after it has already been learned but then
forgotten…
• Relearning can be a more sensitive measure of memory
than either recall or recognition because it allows assessing
memory in terms of “how much” or “how fast” rather than
simply “correct” versus “incorrect” responses.
• Relearning also allows us to measure memory for
procedures like driving a car or playing a piano piece, as
well as memory for facts and figures.
Semantic Network Model
• Information in long-term memory is clustered and associated.
• Clustering means organizing items into related groups, or clusters
during recall.
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• There are several models to show how information is organized in
long-term memory.
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• One such model is the semantic network model which is a useful
way of conceptualizing how information is organized in long-term
memory.
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• When one concept is activated in the semantic network, it can
spread in any number of directions, activating other associations in
the semantic network.
Why do we forget?
• Encoding refers to the process of transforming
information into a form that can be entered and
retained by the memory system.
• A reason as to why we tend to forget is that we never
encoded the information into long-term memory, also
called
• Encoding failure
• Sometimes we encode automatically…the letters on a
number 5
• Encoding memory failure tends to explain everyday
memory failures such as absent-mindedness.
• Absent-mindedness tends to occur because we do not
tend to or encode the information at the time when it
is presented.
• Interference theory; retroactive/proactive interference
• Freud argued that we implement ego defense
mechanisms when memories become too
unpleasant, we tend to either suppress them,
deliberately, consciously making the effort to
forget the information.
• Repression is the motivated forgetting that
occurs unconsciously.
• Suppression is the motivated forgetting that
occurs consciously
• The inability to recall long-term memories
because of inadequate or missing retrieval cues is
retrieval cue failure.
Retrieval Failure
• Retrieval refers to the process of accessing, or retrieving stored memories
• So we tend to forget when we do not encode or because stored memories
may decade
• When one memory is competing with or replacing another memory, we
tend to forget; this process is __________
• interference theory.
• In retroactive interference occurs when a new memory interferes with
remembering an old memory; while proactive interference occurs when
an old memory interferes with remembering a new memory.
• When trying to recall information from a list, we sometimes experience
retrieval failure due to the serial position effect. The serial position effect
refers to the tendency to easily retrieve information from the beginning
and the end of the list than from the middle.
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• The primacy effect is the tendency to recall the first items in a list, and the
recency effect, the tendency to recall items from the end of the list.
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• One of the best ways to increase access to information in memory is to
retrace or recreate the original learning condition, the encoding specifity
principle.
Memory Construction
• Elizabeth Loftus is on the forefront of research of
memory distortion. Through her research, Loftus
confirmed that post event exposure to misinformation
can distort the recollection of the original event.
• Confusion can also arise when the true source of the
memory is forgotten or when a memory is attributed
to the wrong source, a phenomenon called source
confusion.
• False memories are distorted or fabricated memories
of events that did not happen, however, the false
memory may feel authentic and is often accompanied
by all the emotional distress that surrounds real
memories.
Accuracy and Inaccuracy in Memory
and Cognition
• Cognitive biases are also known to influence memory.
• Cognitive biases are errors in memory or judgment that are
caused by the inappropriate use of cognitive processes.
• Confirmation bias leads to faulty processing in that the
person seeks information that verifies and confirms already
held beliefs
• Functional fixedness impedes problem solving and
cognitive processing in that persons only see objects for the
purposes intended.
• Salience, we tend to remember the exception, not the rule.
• Cognitive accessibility, is the idea that some memories are
more highly activated than others.
• Similar to developing false memories, research has
shown that people can be led to develop beliefs and
memories for events that did not happen to them.
• We must be very careful when interviewing children
regarding events that they have experienced,
memories for events before the age of 3 are unreliable
• Hypnosis, to recover memories ripped families apart
• We recover memories all the time…with the right
retrieval cues
• A retrieval cue is a prom or hint that can help trigger
recall of a stored memory.
• With significant or rare moments, flashbulb memory is
thought to involve the recall of very specific details or
images surrounding those significant, rare, or vivid
memories.
• With the right retrieval cue, you can often access
stored information that seemed to be completely
unavailable.
• Mood tends to evoke memories that are consistent
with the mood, a tendency called mood congruence
• Vividly imagining an event markedly increases
confidence that the event actually occurred in
childhood, an event called imagination inflation.
• When we retain a memory for an event but not the
context in which we acquired it, we are experiencing
source amnesia…attributing to the wrong source an
event we have experienced, heard about, read about,
or imagined…
• Source amnesia, along with the misinformation effect,
is at the heart of many false memories
Improving memories
• Study the material, engage in various encoding techniques such as
self-referencing or elaborate rehearsal
• The use of elaborative rehearsal, self-referencing with visual
imagery enhances encoding.
• Make the material meaningful
• Activate retrieval cues… Environment can cue certain memories,
The context effect is the tendency to remember information more
easily when the retrieval occurs in the same setting in which you
originally learned the information
• Whereas context-dependent learning refers to a match in the
external situation between learning and remembering, statedependent learning refers to superior retrieval of memories when
the individual is in the same physiological or psychological state as
during encoding.
• When trying to recall information from a list, we sometimes
experience retrieval cue failure due to the serial position effect
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• Put things into categories…
• Memories that are stored in LTM are not isolated but
rather are linked together into categories—networks of
associated memories that have features in common
with each other…remember the semantic network
model, organization improves memory
• Some categories have defining features that must be
true of all members of the category.
• Members of categories (even those with defining
features) can be compared to the category prototype,
which is the member of the category that is most
average or typical of the category.
• We retrieve information that is prototypical of a
category faster than we retrieve information that is less
prototypical
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Use mnemonic devices
Minimize interference
Sleep..memory consolidation takes place during sleep
Test yourself
What can impair memory performance…
When pathways in these neural networks are frequently
and repeatedly fired, the synapses become more efficient
in communicating with each other, and these changes
create memory. This process, known as long-term
potentiation (LTP), refers to the strengthening of the
synaptic connections between neurons as result of frequent
stimulation…drugs can distress this process.
• Because the new patterns of activation in the synapses take
time to develop, LTP happens gradually. The period of time
in which LTP occurs and in which memories are stored is
known as the period of consolidation.
• Drugs that block LTP reduce learning, whereas drugs that
enhance LTP increase learning
The Hippocampus
• The hippocampus helps us encode information about
spatial relationships, the context in which events were
experienced, and the associations among memories.
• The hippocampus also serves in part as a switching
point that holds the memory for a short time and then
directs the information to other parts of the brain, such
as the cortex, to actually do the rehearsing,
elaboration, and long-term storage.
• Without the hippocampus, which might be described
as the brain’s “librarian,” our explicit memories would
be inefficient and disorganized.
• Different brain structures
help us remember different
types of information. The
hippocampus is particularly
important in explicit
memories, the cerebellum
is particularly important in
implicit memories, and the
amygdala is particularly
important in emotional
memories.
• The hippocampus is
handling explicit memory,
the cerebellum and the
amygdala are
concentrating on implicit
and emotional memories,
respectively.
• Research shows that the cerebellum is more active
when we are learning associations and in priming tasks,
and animals and humans with damage to the
cerebellum have more difficulty in classical
conditioning studies.
• The storage of many of our most important emotional
memories, and particularly those related to fear, is
initiated and controlled by the amygdala.
• Evidence for the role of different brain structures in
different types of memories comes in part from case
studies of patients who suffer from amnesia, a
memory disorder that involves the inability to
remember information.
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Some memories seem to be localized at specific spots in the brain. A memory trace is the brain changes that are
associated with a particular stored memory.
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Processing Memories in the Brain
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For people who suffer damage to the brain, for instance, as a result of a stroke or other trauma, the
amnesia may work backward.
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Amnesia is severe memory loss and is characterized by two types.
People that have retrograde amnesia are unable to remember some or all of their past, especially episodic
memories for recent events.
Retrograde amnesia often results from a blow to a head.
LTP takes time (the process of consolidation), retrograde amnesia is usually more severe for memories that
occurred just prior to the trauma than it is for older memories, and events that occurred just before the
event that caused memory loss may never be recovered because they were never completely encoded.
Organisms with damage to the hippocampus develop a type of amnesia that works in a forward direction
to affect encoding, known as anterograde amnesia.
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The inability to form new memories is anterograde amnesia.
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Henry Gustav Molaison (before he died in 2008, he was referred to only as H. M.) who had parts of his
hippocampus removed to reduce severe seizures .
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Following the operation, Molaison developed virtually complete anterograde amnesia. Although he could
remember most of what had happened before the operation, and particularly what had occurred early in
his life, he could no longer create new memories. Molaison was said to have read the same magazines
over and over again without any awareness of having seen them before.
• Alzheimer’s Disease
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• Dementia is a broad term that refers to the
decline and impairment of memory, reasoning,
language, and other cognitive functions.
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• The most common form of dementia is
Alzheimer’s disease which is irreversible.
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• Researchers still don’t know what causes
Alzheimer’s disease.
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