CHAPTER 6 -OUTLINE : Memory
I. Introduction: What Is Memory?
Memory refers to the mental processes that enable us to retain and use
information over time. Memory involves three fundamental processes:
1. Encoding is the process of transforming information into a form
that can be entered into and retained by the memory system.
2. Storage is the process of retaining information in memory so that it
can be used at a later time.
3. Retrieval is the process of recovering the stored information so that
we are consciously aware of it.
A. The Stage Model of Memory
The stage model of memory describes memory as consisting of three
distinct stages: sensory memory, short-term memory, and long-term
memory. It is based on the idea that information is transferred from one
memory stage to another.
1. Sensory memory, the first stage of memory, registers a great deal
of information from the environment and holds it for a very brief
period of time (1⁄4 second to 3 seconds). The information you “select,”
or pay attention to, is transferred to the next stage of memory.
2. Short-term memory is the active, working memory in which information
is stored for about 20 seconds. It temporarily holds all the
information you are currently thinking about or consciously aware
of.
3. Long-term memory, the third stage of memory, represents the
long-term storage of information.
a. The transfer of information between short-term and long-term
memory is a two-way street, flowing from long-term to shortterm
as well.
b. Even the most routine cognitive tasks involve processing current
sensory data and retrieving relevant stored information.
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B. Sensory Memory: Fleeting Impressions of the World
1. The Duration of Sensory Memory
a. In 1960, George Sperling conducted experiments from which
he was able to identify the duration of visual sensory memory.
b. Sperling’s classic experiment demonstrated that our visual sensory
memory holds a great deal of information very briefly (for
about half a second).
2. Types of Sensory Memory: Pick a Sense, Any Sense!
a. Memory researchers believe that a separate sensory memory
exists for each sense (vision, hearing, touch, smell, and taste).
b. Visual sensory memory, sometimes referred to as iconic memory,
typically holds an image, or icon, for about one-quarter to onehalf
second.
c. Auditory sensory memory, sometimes referred to as echoic
memory, holds sound information up to three or four seconds.
3. An important function of sensory memory is to briefly store sensory
impressions so they overlap slightly with one another such that we
perceive the world around us as continuous, rather than as a series
of disconnected visual images or disjointed sounds.
C. Short-Term, Working Memory: The Workshop of Consciousness
1. Short-term, or working, memory provides temporary storage for
information transferred from sensory and long-term memory.
2. The Duration of Short-Term Memory
a. You can hold most types of information in short-term memory up
to about 20 seconds before it is forgotten.
b. Maintenance rehearsal is the mental or verbal repetition of
information in order to maintain it beyond the usual 30-second
duration of short-term memory.
c. Information that is not actively rehearsed quickly fades, or
decays.
d. Another potential cause of forgetting is interference from new or
competing information.
3. The Capacity of Short-Term Memory
a. Short-term memory has a relatively limited capacity of between
five and nine—the magical number seven, plus or minus two—
items, or bits of information.
b. When the capacity is reached, new information will displace, or
bump out, currently held information.
c. Chunking increases the amount of information that can be held
in short-term memory by grouping related items together into a
single unit. To do so, chunking also often involves the retrieval of
meaningful information from long-term memory.
4. From Short-Term Memory to Working Memory
a. Short-term memory is sometimes called working memory
because of its involvement in many mental activities, including
reading, reasoning, mental imagery, and problem solving.
b. Working memory is defined as a short-term memory system
involved in the temporary storage and active manipulation of
information.
c. Alan Baddeley’s model of working memory includes three main
components, each of which can function independently.
(1) The phonological loop is specialized for verbal material.
(2) The visuospatial sketchpad is specialized for spatial or visual
material.
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(3) The central executive controls attention, integrates information,
and manages the activities of the other two components.
It also initiates retrieval and decision processes.
d. The term working memory is generally used when the focus is on
active, conscious, mental “work,” such as language comprehension,
problem solving, or reasoning. The term short-term memory
is more likely used when the focus is on simpler memory
processes, such as the rehearsal of lists of syllables, words, or
numbers.
D. Long-Term Memory
1. Long-term memory, the storage of information over extended periods
of time, has a limitless capacity. Retrieving information from
long-term memory usually happens quickly and with little effort.
2. Encoding Long-Term Memories
An important function that occurs in short-term memory is encoding,
or the transformation of new information into a form that can be
retrieved later.
a. Elaborative rehearsal is an effective technique for encoding
and transferring information into long-term memory. You relate
the new information to other information you already know; that
is, you elaborate on the new information in some meaningful
way.
b. Two factors that enhance encoding are
(1) the self-reference effect—applying information to yourself
(2) visual imagery—using vivid images
3. Types of information in long-term memory
a. Procedural memory refers to the long-term memory of how to
perform different skills, operations, and actions.
b. Episodic memory refers to your long-term memory of specific
events or episodes in your life, including the time and place that
they occurred. Autobiographical memory refers to the events of
your life—your personal life history.
c. Semantic memory refers to general knowledge that includes
facts, names, definitions, concepts, and ideas stored in long-term
memory.
4. Implicit and Explicit Memory: Two Dimensions of Long-Term
Memory
Studies of patients with amnesia indicate that long-term memory is
composed of two separate but interacting subsystems and abilities:
a. Explicit memory is memory with awareness—information or
knowledge that can be consciously recollected, including episodic
and semantic memory. Also called declarative memory.
b. Implicit memory is memory without awareness—memories
that cannot be consciously recollected, but that still affect behavior,
knowledge, or performance of some task. Also called nondeclarative
memory.
5. Culture and Human Behavior: Culture’s Effect on Early Memories
Cultural differences in the sense of self influence the content of
ourru earliest memories. In one experiment, Americans’ memories
were more discrete, one-point-in-time events, whereas Asian students
had more general, routine memories. Shared reminiscing also
differs in Western and Asian cultures.
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6. The Organization of Information in Long-Term Memory
Information in long-term memory is organized, although exactly how
it is organized is not completely understood by memory researchers.
They do know, however, that it is clustered and associated.
a. Clustering means organizing items into related groups, or
clusters, during recall.
b. Different pieces of information are also logically linked, or
associated.
c. The semantic network model is a model that describes units
of information in long-term memory as being organized in a complex
network of associations. When one concept is activated in
the semantic network, it can spread in any number of directions,
activating other associations in the network.
II. Retrieval: Getting Information from Long-Term Memory
A. The Importance of Retrieval Cues
1. Retrieval refers to the process of accessing, or retrieving, stored
information in long-term memory.
2. A retrieval cue is a clue, prompt, or hint that helps trigger recall of
a stored memory.
3. Retrieval cue failure is the inability to recall long-term memories
because of inadequate or missing retrieval cues.
4. Common Retrieval Cue Failures: The Tip-of-the-Tongue Experience
a. The tip-of-the-tongue (TOT) experience, a common example
of retrieval failure, refers to the inability to get at a bit of information
that you are certain is stored in your memory.
b. Tip-of-the-tongue experiences illustrate several aspects of the
retrieval process:
(1) Retrieving information is not an all-or-nothing process.
(2) Information stored in memory is organized and connected in
relatively logical ways.
5. Testing Retrieval: Recall, Cued Recall, and Recognition
a. Recall, also called free recall, involves producing information
using no retrieval cues. This memory measure is used on essay
tests.
b. Cued recall involves remembering an item of information in
response to a retrieval cue. Fill-in-the-blank and matching
questions are examples of cued-recall tests.
c. Recognition involves identifying the correct information from
several possible choices. Multiple-choice tests involve recognition
as a measure of long-term memory.
6. The Serial Position Effect
The serial position effect refers to the tendency to retrieve information
more easily from the beginning and the end of a list rather
than from the middle. There are two parts to the serial position
effect:
a. The tendency to recall the first items in a list is called the
primacy effect. This is especially prominent when you have to
engage in serial recall.
b. The tendency to recall the final items in a list is called the
recency effect.
B. The Encoding Specificity Principle
The encoding specificity principle is the principle that when the
conditions of information retrieval are similar to the conditions of
information encoding, retrieval is more likely to be successful.
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1. The Context Effect
The context effect is the tendency to remember information more
easily when the retrieval occurs in the same setting as the original
learning of the information.
2. Mood Congruence
Mood congruence refers to the idea that a given mood tends to
evoke memories that are consistent with that mood.
C. Flashbulb Memories: Vivid Events, Accurate Memories?
1. A flashbulb memory is the recall of very specific images or details
surrounding a vivid, rare, or significant personal event.
2. Flashbulb memories are said to be characterized by a high degree of
distinctiveness; that is, the encoded information represents a unique,
different, or unusual memory.
3. The accuracy of flashbulb memories—like that of normal
memories—declines over time. What distinguishes flashbulb
memories from ordinary memories is the high degree of confidence
people have in their accuracy.
III. Forgetting: When Retrieval Fails
Forgetting is the inability to recall information that was previously
available.
A. Hermann Ebbinghaus: The Forgetting Curve
1. German psychologist Hermann Ebbinghaus used himself as a
research subject to study how much information was forgotten after
different lengths of time.
2. Ebbinghaus tested his recall of nonsense syllables (combinations of
two consonants and one vowel) and plotted his results in the forgetting
curve, which reveals two distinct patterns in the relationship
between forgetting and the passage of time.
a. Much of what we forget is lost relatively soon after we originally
learn it.
b. The amount of forgetting eventually levels off.
B. Why Do We Forget?
1. Encoding Failure: It Never Got to Long-Term Memory
One cause of forgetting, encoding failure, is the inability to recall
specific information because of insufficient encoding of the information
for storage in long-term memory.
a. Absent-mindedness is a form of encoding failure that occurs
because you don’t pay enough attention to a bit of information
when you should be encoding it. Absent-minded memory failures
often occur because your attention is divided.
b. Absent-mindedness is also implicated in prospective memory,
remembering to do something in the future. Prospective memory
failures are due to retrieval cue failure—the inability to recall a
memory because of missing or inadequate retrieval cues.
2. Decay Theory: Fading with the Passage of Time
Decay theory is the view that forgetting is due to normal metabolic
processes that occur in the brain over time. New memories create
memory traces, which, if not used, fade with time. Researchers have
found no compelling evidence to support this theory; however, many
believe that decay does somehow contribute to forgetting.
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3. Interference Theory: Memories Interfering with Memories
Interference theory is the theory that forgetting is caused by one
memory competing with or replacing another.
a. Retroactive interference is forgetting in which a new memory
interferes with remembering an old memory.
b. Proactive interference is forgetting in which an old memory
interferes with remembering a new memory.
4. Motivated Forgetting: Forgetting Unpleasant Memories
Motivated forgetting refers to the idea that we forget because we
are motivated to forget, usually because a memory is unpleasant or
disturbing.
a. Suppression is motivated forgetting that occurs consciously;
that is, a person makes a deliberate, conscious effort to forget
information.
b. Repression is motivated forgetting that occurs unconsciously:
that is, all memory of an event or experience is blocked from
conscious awareness. Among psychologists, repression is a controversial
topic.
5. In Focus: Déjà Vu: An Illusion of Memory
The term déjà vu, French for “already seen,” refers to a brief but
intense feeling of having experienced something before. These are
experienced by about two-thirds of individuals. Déjà vu experiences
may be disruptions in source memory, or source monitoring, our
ability to remember the original details of a memory. Encoding failure
may also be implicated.
IV. Imperfect Memories: Errors, Distortions, and False Memories
Every new memory you form is not simply recorded, but actively constructed.
To form a new memory, you actively organize and encode information. When
you later attempt to retrieve those details from memory, you actively reconstruct,
or rebuild, the memory.
1. The Misinformation Effect: The Influence of Postevent Information
on Misremembering
a. In a now-classic study, psychologist Elizabeth Loftus had subjects
watch a film of an automobile accident. After the film, she
asked the critical question: “About how fast were the cars going
when they contacted/hit/bumped/collided/or smashed each
other?” A week after subjects saw the film, they were asked
whether they had seen any broken glass. Because many subjects
whose question used the word smashed reported inaccurate
information, this study demonstrated how new information can
distort the reconstruction of memories.
b. The misinformation effect is a memory-distortion phenomenon
in which people’s existing memories can be altered by exposing
them to misleading information.
2. Source Confusion: Misremembering the Source of a Memory
Source confusion is a memory distortion that occurs when the true
source of the memory is forgotten.
3. A false memory is a distorted or inaccurate memory that feels completely
real and is often accompanied by all of the emotional impact
of a real memory.
4. Schemas, Scripts, and Memory Distortions: The Influence of Existing
Knowledge on What Is Remembered
a. Schemas are organized clusters of knowledge and information
about particular topics. Schemas are useful in forming new
memories, but they can also contribute to memory distortions.
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b. One kind of schema, called a script, involves the typical
sequence of actions and behaviors at a common event.
c. Memories can easily become distorted: We remember objects and
events as we expect them to be, not as they actually are.
A. Forming False Memories: From the Plausible to the Impossible
1. Imagination Inflation: Remembering Being Lost in the Mall
a. In the lost-in-the-mall study, Loftus and Pickrell were able to
create false memories by having participants remember real
events along with imagining pseudoevents. This research strategy
has been dubbed the lost-in-the-mall technique.
b. Imagination inflation is a memory phenomenon in which
vividly imagining an event markedly increases confidence that
the event actually occurred.
c. Several factors are involved in creating a compelling memory
from imagining an event.
(1) Repeatedly imagining the event makes the event seem familiar;
this familiarity is misinterpreted as an indication that
the event really happened.
(2) People experience source confusion, that is, confusion arises
over whether a retrieved memory is based on a real or imagined
event.
(3) The more vivid and detailed the imaginative experience, the
more likely people will confuse the imagined and real events.
d. Simple manipulations, such as suggestions, imagination exercises,
vivid memory cues, and photographs, can increase the incidence
and realism of false memories.
2. Critical Thinking: The Memory Wars: Recovered or False Memories?
a. In the 1990s, proponents of recovery therapy (trauma therapy,
repressed memory therapy) claimed to have identified the root
cause of many psychological problems—sexual abuse in childhood.
They asserted that many adult “survivors” had completely
repressed all memories of the abuse.
b. Critics contend that many of the supposedly “recovered” memories
are actually false memories produced by the suggestions of
well-intentioned but misguided therapists.
V. The Search for the Biological Basis of Memory
A. The Search for the Elusive Memory Trace
1. Pavlov believed that the memory involved in learning a classically
conditioned response would be explained as a matter of changes in
the brain.
2. In the 1920s, American physiological psychologist Karl Lashley
began the search for the memory trace, or engram—the brain
changes associated with the formation of a long-term memory.
a. He believed that memory was localized—a particular memory is
stored in a specific brain area.
b. Lashley systematically removed different sections of the cerebral
cortex in rats trained to run a maze, but he failed to find a specific
location for the memory.
c. At the end of his career, Lashley concluded that memories are
not localized in specific locations, but instead are distributed, or
stored throughout the brain. This assumption was not entirely
correct either.
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3. American psychologist and neuroscientist Richard F. Thompson
confirmed Pavlov’s belief that some memories are localized, or
stored, in specific areas of the brain. He found that in rabbits a classically
conditioned eye-blink response was formed and stored in a
small area of the cerebellum.
4. Combining the findings of Lashley and Thompson suggests that
memories have the potential to be both localized and distributed;
very simple memories may be localized in a specific area, whereas
more complex memories seem to be distributed throughout the
brain.
5. Focus on Neuroscience: Assembling Memories: Echoes and
Reflections of Perception
Studies have confirmed that retrieving a sensory memory reactivates
the sensory area of the cortex that was involved in the initial perception
of the event. Memories that involve more than one sense tend to
reactivate multiple sensory areas of the brain.
B. The Role of Neurons in Long-Term Memory
1. The notion of a memory trace suggests that some change must occur
in the workings of the brain when a new long-term memory is
stored. Two possible changes could occur:
a. The functioning of the neurons could change.
b. The structure of the neurons could change.
2. In the last 30 years, memory researchers have studied Aplysia, a sea
snail with only about 20,000 good-sized neurons. Eric Kandel has
studied the neuronal changes that occur when Aplysia forms a new
memory for a simple classically conditioned response.
a. The function of the neurons is altered; there is an increase in the
amount of the neurotransmitters produced by the neurons.
b. The structure of the snail’s neurons also changes; the number of
interconnecting branches between the neurons increases, as do
the number of synapses, or communication points, on each
branch.
c. Collectively, these changes are called long-term potentiation,
which refers to a long-lasting increase in synaptic strength.
d. Forming a memory seems to produce distinct functional and
structural changes in specific neurons. These changes create a
memory circuit. As the changes in the neurons strengthen the
communication links in this circuit, the memory becomes established
as a long-term memory.
C. Processing Memories in the Brain: Clues from Amnesia
Amnesia is severe memory loss.
1. Retrograde Amnesia: Disrupting Memory Consolidation
Retrograde amnesia is loss of memory, especially for episodic
information. Retrograde means “backward moving.”
a. Memory consolidation is the gradual, physical process of
converting new long-term memories to stable, enduring memory
codes.
b. If memory consolidation is disrupted before the process is complete
(e.g., by brain trauma or drugs), memories of the events
that immediately preceded the brain trauma are completely lost.
2. Anterograde Amnesia: Disrupting Explicit Memory Formulation
Anterograde amnesia is the inability to form new memories.
Anterograde means “forward moving.” The case of H.M., who was
studied extensively by Brenda Milner and Suzanne Corkin, provided
insight into understanding how the brain processes
memory. (Note that H.M. died in December 2008 at the age of 82.)
a. Following the removal of portions of his temporal lobe, including
the hippocampus to reduce epileptic seizures, H.M. was unable
to form new memories of events and information. This suggests
that the critical role of the hippocampus seems to be the encoding
of new memories for events and information and the transfer
of them from short-term to long-term memory.
b. Cases of anterograde amnesia have contributed to our understanding
of the distinction between implicit memories and
explicit memories.
(1) H.M. could not form new episodic or semantic memories,
which reflect the explicit memory system; H.M. could form
new procedural memories, which reflect the implicit memory
system.
(2) Therefore, the hippocampus is less crucial to the formation of
new implicit memories, such as procedural memories, than
to the formation of new explicit memories.
3. In Focus: H.M. and Famous People
When H.M.’s hippocampus was removed, psychologists questioned
whether other areas of the brain might support some limited learning
of new knowledge. H.M. was tested on learning last names of
people who became famous after his surgery. He had acquired some
declarative semantic knowledge, including details about some of the
famous people
4. Brain Structures Involved in Memory
a. The cerebellum is involved in the classical conditioning of simple
reflexes and in procedural and other motor skill memories.
b. The amygdala seems to encode the emotional qualities associated
with particular memories, such as fear or anger, as well as
memories of sensory stimuli that are associated with rewards
and punishments.
c. The frontal lobes are involved in retrieving and organizing information
associated with autobiographical and episodic memories.
d. The prefrontal cortex seems to play an important role in memory,
especially in the ability to remember the order of information.
e. The medial temporal lobes are involved in encoding complex
memories by forming links among the information stored in multiple
brain regions.
5. Alzheimer’s Disease
a. Dementia is characterized by decline and impairment of
memory, reasoning, language, and other cognitive functions.
Alzheimer’s disease (AD) is the most common cause of
dementia.
b. The brains of AD patients develop an abundance of two
abnormal structures—beta-amyloid plaques and neurofibrillary
tangles.
6. Focus on Neuroscience: Mapping Brain Changes in Alzheimer’s
Disease
Alzheimer’s disease progressively destroys neurons in the brain. The
disease first attacks the temporal lobes, affecting areas involved in
memory. Next affected are the frontal areas, which are involved in
thinking, reasoning, self-control, and planning. There is also significant
loss in the limbic areas, involved in regulating emotion.
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VI. Application: Superpower Memory in Minutes Per Day!
Effective techniques to enhance memory include the following:
1. Focus your attention.
2. Commit the necessary time.
3. Space your study sessions.
4. Organize the information.
5. Elaborate on the material.
6. Use visual imagery.
7. Use a mnemonic device.
8. Explain it to a friend.
9. Reduce interference within a topic.
10. Counteract the serial position effect.
11. Use contextual cues to jog memories.
12. Sleep on it to help consolidate those memories.
13. Forget the ginkgo biloba.