CHAPTER
OUTLINE
I.
Introduction: What Is Memory?
A.
Memory is a group of related mental processes that are involved in acquiring, storing,
and retrieving information. 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.
B.
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. The information you “select,” or pay
attention to, is transferred to the next stage of memory.
2.
Short-term memory, or working memory, is the active stage of memory in which
information is stored for about 30 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 short-term as well.
b.
Even the most routine cognitive tasks involve processing current sensory data and
retrieving relevant stored information.
C.
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
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 one-half 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.
D.
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 30 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.
(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.
E.
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.
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
c.
The levels-of processing framework proposes that the level at which new information is
processed determines how well the new information will be encoded and remembered. Information
processed at a “deeper” level is more likely to be remembered than information processed at a
“shallow” level.
(1)
Deep processing involved processing the meaning of the new information, rather than
its more superficial characteristics.
(2)
Deep processing also involves relating the details you wish to remember to each other
as well as to information already stored in your memory.
(3)
According to this framework, maintenance rehearsal represents shallow processing and
elaboration rehearsal represents deep processing.
(4)
One problem with this framework is the difficulty in defining and quantifying the
“levels.”
3.
Types of information in long-term memory
a.
Procedural memory refers to long-term memory of how to perform different skills,
operations, and actions.
b.
Episodic memory refers to 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.
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 longterm 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.
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.
4.
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.
5.
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.
1.
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 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 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.
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 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.
3.
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 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.
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.
A.
The Misinformation Effect: The Influence of Postevent Information on Misremembering
1.
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.
2.
The misinformation effect is a memory-distortion phenomenon in which people’s
existing memories can be altered by exposing them to misleading information.
B.
Source Confusion: Misremembering the Source of a Memory
1.
Source confusion is a memory distortion that occurs when the true source of the
memory is forgotten.
2.
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.
C.
Schemas, Scripts, and Memory Distortions: The Influence of Existing Knowledge on
What Is Remembered
1.
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.
2.
One kind of schema, called a script, involves the typical sequence of actions and
behaviors at a common event.
3.
Memories can easily become distorted: We remember objects and events as we expect
them to be, not as they actually are.
D.
Forming False Memories: From the Plausible to the Impossible
1.
Imagination inflation
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.
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 the
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 imaged event.
(3)
The more vivid and detailed the imaginative experience, the more likely people will
confuse the imagined and real events.
2.
Vivid details, vivid false memories
a.
Simple manipulations such as suggestions, imagination exercises, vivid memory cues,
and photographs can increase the incidence and realism of false memories.
b.
(Critical Thinking) Recovering “repressed” memories of childhood sexual abuse
(1)
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.
(2)
Critics contend that many of the supposedly “recovered” memories are actually false
memories produced by the suggestions of well-intentioned but misguided therapists.
.
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 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.
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) Recent 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 longlasting 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 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 is the inability to form new memories. Anterograde means
“forward moving.” The case of H. M. provided insight into understanding how the brain processes
memory.
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. cannot form new episodic or semantic memories, which reflect the explicit
memory system; H. M. can 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.
c.
Infantile amnesia is the inability to remember infant experiences during adulthood.
(1)
One explanation involves language development; that is, young children can remember
events from the period between ages 2 and 3 but are unable to describe them in words.
(2)
Another explanation involves brain development. Infants lack the ability to encode and
store new episodic memories but do have the ability to form procedural memories. Some researchers
believe that the hippocampus does not mature until about 2 years of age. If true, then the infant’s
hippocampus may not be able to encode and store events and experiences in long-term memory.
D.
Brain Structures Involved in Memory
1.
The cerebellum is involved in the classical conditioning of simple reflexes and in
procedural and other motor skill memories.
2.
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.
3.
The frontal lobes are involved in retrieving and organizing information associated with
autobiographical and episodic memories.
4.
The prefrontal cortex seems to play an important role in memory, especially in the
ability to remember the order of information.
5.
The medial temporal lobes are involved in encoding complex memories by forming links
among the information stored in multiple brain regions.
E.
Alzheimer’s Disease
1.
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.
2.
The brains of AD patients develop an abundance of two abnormal structures—betaamyloid plaques and neurofibrillary tangles.
3.
(Focus on Neuroscience) 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.