Chapter 7: Human Memory
- semantic memory - memory for general information
- episodic memory - memory for personal events
- Encoding - involves forming a memory code
- Storage - involves maintaining encoded information in memory
- Retrieval - involves recovering information from memory stores
KEY POINTS IN THIS CHAPTER (pages 269-273)
- Three key processes contribute to memory: encoding, storage, and retrieval. The nextin-line effect illustrates that active encoding is crucial to memory
- Attention, which facilitates encoding, is inherently selective and has been compared to
a filter. The cocktail party phenomenon suggests that input is screened late in mental
processing. The empirical evidence indicates that people may have some flexibility in
where they place their attention filter
- According to levels-of-processing theory, the kinds of memory codes people create
depend on which aspects of a stimulus are emphasized. Structural, phonemic, and
semantic encoding emphasize the structure, sound and meaning of words,
respectively
- Deeper processing results in better recall of information. Structural, phonemic, and
semantic encoding represent progressively deeper levels of processing
- Elaboration enriches encoding by linking a stimulus to other information, such as
examples of an idea. The creation of visual images to represent words can enrich
encoding. Visual imagery may help by creating two memory codes rather than just
one. Encoding that emphasizes personal self-reference may be especially useful in
facilitating retention
Encoding: Getting Information into Memory
- next-in-line effect - impaired recall for an event immediately preceding an
anticipated public performance.
The Role of Attention
- Attention - involves focusing awareness on a narrowed range of stimuli or events
- selective attention is critical to everyday functioning - filter out most of the potential
stimulation around you to be able to focus attention
- often compared to a filter that screens out most potential stimuli while allowing a select
few pass through into conscious awareness
- The cocktail party phenomenon suggests that attention involves late selection, based
on the meaning of input
- The empirical evidence indicates that people may have some flexibility in where they
place their attention filter (see page 269 figure 7.2)
- people have difficulty if they attempt to focus their attention on two or more inputs
simultaneously - large reductions in memory performance
- divided attention can have a negative impact on the performance of a variety of tasks,
especially complex or unfamiliar ones
- information encoded from effortful processing and automatically
Chapter 7: Human Memory
Levels of Processing
- levels-of-processing theory - proposes that deeper levels of processing result in
longer-lasting memory codes
- According to levels-of-processing theory, the kinds of memory codes people create
depend on which aspects of a stimulus are emphasized.
- when dealing with verbal information, people engage in three progressively deeper
levels of processing: structural, phonemic, and semantic encoding
- structural encoding - relatively shallow processing that emphasizes the physical
structure of the stimulus
- phonemic encoding - further processing that emphasizes what a word sounds like naming or saying (possibly silently) the words
- semantic coding - even deeper processing that emphasizes the meaning of verbal
input - thinking about the objects and actions the words represent
- the “levels” remain vaguely defined (time is not a reliable index of depth of processing)
Enriched Encoding
- other dimensions to encoding that can enrich the encoding process and thereby
improve memory
ELABORATION
- Semantic encoding can be enhanced through elaboration
- Elaboration - linking a stimulus to other information at the time of encoding
- often consists of thinking of examples that illustrate an idea
VISUAL IMAGERY
- Imagery - the creation of visual images to represent the words to be remembered
- it is easier to form images of concrete objects than of abstract concepts
- imagery facilitates memory because it provides a second kind of memory code, and
two codes are better than one
- Pavlov
- dual-coding theory - holds that memory is enhanced by forming semantic and visual
codes, since either can lead to recall
SELF-REFERENT ENCODING
- Encoding that emphasizes personal self-reference
- self-referent encoding - involves deciding how or whether information is personally
relevant
KEY POINTS IN THIS CHAPTER (pages 273-282)
- Information-processing theories of memory assert that people have three kindʼs of
memory stores: a sensory memory, a short-term memory, and a long-term memory.
The sensory store preserves information in its original form, probably for only a fraction
of a second
- Short-term memory has a limited capacity of about seven chunks of information. STM
can maintain unrehearsed information for up to about 20 seconds. Short-term memory
is working memory, and it appears to involve more than a simple rehearsal loop.
Chapter 7: Human Memory
According to Baddeley, working memory also includes a visuospatial sketchpad, an
executive control system, and an episodic buffer.
- Long-term memory is an unlimited capacity store that may hold information indefinitely.
Penfieldʼs ESB research and the existence of flashbulb memories suggest that LRM
storage may be permanent, but the evidence is not convincing. Our Featured Study
showed that flashbulb memories are not as accurate as claimed. Some theorists have
questioned the distinction between short-term and long-term memory
- Information in long-term memory can be organized in simple clusters or multilevel
classification systems called conceptual hierarchies. A schema is an organized cluster
of knowledge about a particular object or sequence of events
- Semantic networks consist of concepts joined by pathways. research suggests that
activation spreads along the paths of semantic networks to activate closely associated
words. Parallel distributed processing models of memory assert that specific memories
correspond to particular patterns of activation in connectionist networks
Storage: Maintaining Information in Memory
- information-processing theories of memory assert that people have three kindʼs of
memory stores: a sensory memory, a short-term memory, and a long-term memory.
- incoming information passes through the sensory store and short-term store before it
is transferred into a long-term store
Sensory Memory
- sensory memory - preserves information in its original sensory form for a brief time,
usually only a fraction of a second
- allows the sensation of a visual pattern, sound, or touch to linger for a brief moment
after the sensory stimulation is over
- vision - called an afterimage
- gives you additional time to try to recognize stimuli
Short-Term Memory
- Short-term memory (STM) - a limited-capacity store that can maintain unrehearsed
information for up to about 20 seconds
- you can maintain information information in your short-term store indefinitely by
engaging in rehearsal - the process of repetitively verbalizing or thinking about the
information
- could go on forever but eventually get distracted and breaks the rehearsal loop
DURABILITY OF STORAGE
- without rehearsal, information in short-term memory is lost in less than 20 seconds
- loss of information from short-term memory is due to time-related decay of memory
traces and interference from competing material.
CAPACITY OF STORAGE
- short-term memory limited in the number of items it can hold
Chapter 7: Human Memory
- can increase the capacity of your short-term memory by combining stimuli into chunks
- a group of familiar stimuli shored as a single unit
- familiarity has to be stored somewhere in long-term memory
SHORT-TERM MEMORY AS “WORKING MEMORY”
- research uncovered that short term memory is not limited to phonemic encoding and
that decay is not the only process responsible for the loos of information from STM
- According to Baddeley, working memory includes a visuospatial sketchpad, an
executive control system, and an episodic buffer on top of phonological rehearsal loop
- phonological rehearsal loop
- visuospstial sketchpad - permits people to temporarily hold and manipulate visual
images
- executive control system - controls the deployment of attention, switching the focus
of attention and dividing attention as needed
- episodic buffer - a temporary, limited-capacity store that allows the various
components of working memory to integrate information and that serves as an
interface between working memory and long term memory
Long-Term Memory
- Look-term memory (LTM) - an unlimited capacity store that can hold information over
lengthy periods of time
- can store information indefinitely
- one point of view is that all information is stored in long-term memory is stored there
permanently, forgetting occurs only because people sometimes cannot retrieve
- Penfield
- reported triggering long-lost memories through electrical stimulation of the brain
(ESB)
- flashbulb memories - unusually vivid and detailed recollections of momentous events
- However..
- Penfield proven inaccurate - remarkable “memories” activated by ESB often included
major distortions or factual impossibilities
- flashbulb memories - neither as accurate nor as special as once believed - become
less detailed and complete with time and are often inaccurate
Are Short-Term Memory and Long-Term Memory Really Separate?
- Some theorists have questioned the distinction between short-term and long-term
memory
- arenʼt all that different
- questioned the concept of sensory memory on the grounds that it may be nothing
more than perceptual processes at work rather than memory
- many ways to view the structure of memory
- one is to view short-term memory as a tine and constantly changing portion of longterm memory that happens to be in a heightened state of activation
- others assert that there is a single, unitary, “generic” memory store that is goverened
by one set of rules and processes
Chapter 7: Human Memory
How Is Knowledge Represented and Organized in Memory?
- what forms do our metal representations of information take?
CLUSTERING AND CONCEPTUAL HIERARCHIES
- Clustering - the tendency to remember similar or related items in groups
- Conceptual hierarchy - a multilevel classification system based on common properties
among items
SCHEMAS
- schema - an organized cluster of knowledge about a particular object or event
abstracted from previous experience with the object or event.
- people are more likely to remember things that are consistent with their schemas than
things that are not
- inverse is also true: people sometimes exhibit better recall of things that violate their
schema-based expectations
- either way, it is apparent that information stored in memory is often organized around
schemas
- relational schemas - representations of typical events surrounding interpersonal
interactions
- represent regularities
SEMANTIC NETWORKS
- Semantic network - consists of nodes representing concepts, joined together by
pathways that link related concepts
- When people think about a word, their thoughts naturally for to related words spreading activation within a semantic network
- Research suggests that activation spreads along the paths of semantic networks to
activate closely associated words.
CONNECTIONIST NETWORKS AND PARALLEL DISTRIBUTION PROCESSING
(PDP) MODELS
- parallel distribution processing - simultaneous processing of the same information that
is spread across networks of neurons.
- connectionist, or parallel distributed processing (PDP) models - assume that cognitive
processes depend on patterns of activation in highly interconnected computational
networks that resemble neural networks
- Parallel distributed processing models of memory assert that specific memories
correspond to particular patterns of activation in connectionist networks
- In semantic networks, specific nodes represent specific concepts or pieces of
knowledge. I n connectionist networks, a piece of knowledge is represented by a
particular pattern of activation across an entire network
KEY POINTS IN THIS CHAPTER (pages 282-285)
- The tip-of-the-tongue pehnomenon shows that recall is often guided by partial
information about a word. Reinstating the context of an event can facilitate recall. This
factor may account for cases in which hypnosis appears to aid recall of previously
Chapter 7: Human Memory
forgotten information. However, hypnosis seems to increase peopleʼ tendency to report
incorrect information
- Memories are not exact replicas of past experiences. As Bartlett showed many years
ago, memory is partially reconstructive. Research on the misinformation effect shows
that information learned after and event can alter oneʼs memory of it
- Source monitoring is the process of making attributions about the origins of memories.
Source-monitoring errors appear to be common and may explain why people
sometimes “recall” something that as only suggested to them or something they only
imagined. Reality monitoring involves deciding whether memories are based on
perception of actual event or on just thinking about the events
Retrieval: Getting Information Out of Memory
Using Cues to Aid Retrieval
- tip-of-the-tongue pehnomenon - the temporary inability to remember something you
know, accompanied by a feeling that itʼs just out of reach
-shows that recall is often guided by partial information about a word.
- memories can be jogged with retrieval cues - stimuli that help gain access to
memories
Reinstating the Context of an Event
- encoding specificity principle
- memory for information would e better when the conditions during encoding and
retrieval were similar
- Reinstating the context of an event can facilitate recall
- recall an event by putting yourself back in the context in which it occurred involves
working with context cues to aid retrieval
- This factor may account for cases in which hypnosis appears to aid recall of previously
forgotten information. However, hypnosis seems to increase peopleʼ tendency to report
incorrect information
- This principle also seems to be true for state and mood-dependent effects too (internal
state)
- might explain red-outs or amnesia by perpetrators of violent crimes
Reconstructing Memories and the Misinformation Effect
- memories are sketchy reconstructions of the past that may be distorted and may
include details that did not actually occur
- Shown by Bartlett many years ago, memory is partially reconstructive (they read a
story twice, waited 15 minutes and then had to write down the tale as best they could
recall. Subjects condensed the story, and frequently changed the tale to some extent)
--> concluded that subjects reconstructed the tale to fit with their established schemas
- misinformation effect
- information learned after and event can alter oneʼs memory of it
- explains why reconstructive distortions show up frequently in eye witness testimony
- mechanisms underlying the effect?
- perhaps “over-writing” explanation
- perhaps new misinformation interferes with the retrieval of the original memory
Chapter 7: Human Memory
- perhaps the subjects can access both the original memory and the altered memory
but have difficulty distinguishing which one was the original --> attributes the
misinformation effect to difficulties in source monitoring
Source Monitoring and Reality Monitoring
- source monitoring - the process of making attributions about the origins of memories
- When people pull up specific memory records, they have to make decisions at the time
of retrieval about where the memories came from
- source-monitoring error - occurs when a memory derived from one source is
misattributed to another source
- Source-monitoring errors appear to be common and may explain why people
sometimes “recall” something that was only suggested to them or something they only
imagined.
- Reality monitoring - the process of deciding whether memories are based on external
sources (oneʼs perceptions of actual events) or internal sources (oneʼs thoughts and
imagination)
KEY POINTS IN THIS CHAPTER (pages 286-293)
- Ebbighausʼs early studies of nonsense syllables suggested that people forget very
rapidly. Subsequent research showed that Ebbinghausʼs forgetting curve was
exceptionally steep
- Forgetting can be measured by asking people to recall, recognize, or relearn
information. Different methods of measuring retention often produce different
estimates of forgetting. Recognition measures tend to yield higher estimates of
retention than recall measures
- Some forgetting, including pseudoforgetting, is due to ineffective encoding of
information. Decay theory proposes that forgetting occurs spontaneously with the
passage of time. It has proven difficult to show that decay occurs in long-term memory
- Interference theory proposes that people forget information because of competition
from other material. Proactive interference occurs when old learning interferes with
new information. Retroactive interference occurs when new learning interferes with old
information
- Forgetting may also be a matter of retrieval failure. According to the encoding
specificity principle, the effectiveness of a retrieval cue depends on how well it
corresponds to the memory code that represents the stored item
- Repression involves the motivated forgetting of painful or unpleasant memories.
Recent years have seen a surge of reports of recovered memories of sexual abuse in
childhood. The authenticity of these repressed memories i the subject of controversy
because empirical studies have demonstrated that it is not all that difficult to create
false memories
- The evidence suggests that therapists can unknowingly create false memories in their
patients and that a significant portion of recovered memories of abuse are the product
of suggestion. But it also seems likely that some cases of recovered memories are
authentic
Chapter 7: Human Memory
Forgetting: When Memory Lapses
How Quickly We Forget: Ebbinghausʼs Forgetting Curve
- Hermann Ebbinghause
- studied forgetting
- invented nonsense syllables - consonant-vowel-consonant arrangements that do not
correspond to words
- forgetting curve - graphs retention and forgetting over time
- suggested that people forget vary rapidly
- further research suggested that Ebbinghausʼs forgetting curve was exceptionally steep
Measures of Forgetting
- Measures of forgetting inevitably measure retention as well
- Retention - the proportion of material retained (remembered)
- results of studies of forgetting may be reported in terms of the amount of forgotten or
the amount retained
- retained interval - the length of time between the presentation of materials to be
remember and the measurement for forgetting
- Three principal methods used toe measure forgetting: recall, recognition, and
relearning
- recall - measure of retention requires subjects to reproduce information on their own
without any cues
- recognition - measure of retention requires subjects to select previously learned
information from an array of options
- relearning - measure of retention requires a subject to memorize information a
second time to determine how much time or how many practice trials are saved by
having learned it before
- Different methods of measuring retention often produce different estimates of
forgetting.
- Recognition measures tend to yield higher estimates of retention than recall measures
Why We Forget
INEFFECTIVE ENCODING
- Some forgetting, including pseudoforgetting, is due to ineffective encoding of
information
- usually due to lack of attention
DECAY
- Decay theory - proposes that forgetting occurs because memory traces fade with time
- It has proven difficult to show that decay occurs in long-term memory
- researchers have repeatedly found that time passage is not as influential as what
happens during the time interval - negative impact of competing information on
retention is called interference
Chapter 7: Human Memory
INTERFERENCE
- Interference theory - proposes that people forget information because of competition
from other material
- interference is assumed to be greatest when intervening material is most similar to
the test material
- Two kinds of interference:
- Retroactive interference occurs when new learning impairs the retention of
previously learned information
- Proactive interference occurs when previously learned information interferes with the
retention of new information
RETRIEVAL FAILURE
- Forgetting may also be a matter of retrieval failure
- Encoding specificity principle - states that the value of a retrieval cue depends on how
well it corresponds to the memory code
- Transfer-appropriate processing - occurs when the initial processing of the information
is similar to the type of processing required by the subsequent measure of retention
MOTIVATED FORGETTING
- Freud theorized that memories there but their retrieval may be blocked by unconscious
avoidance tendencies
- called motivated forgetting or repression - refers to keeping distressing thoughts and
feelings buried in the unconscious
The Repressed Memories Controversy
- Recent years have seen a surge of reports of recovered memories of sexual abuse in
childhood.
- The authenticity of these repressed memories is the subject of controversy because
empirical studies have demonstrated that it is not all that difficult to create false
memories
- The evidence suggests that therapists can unknowingly create false memories in their
patients and that a significant portion of recovered memories of abuse are the product
of suggestion.
- It also seems likely that some cases of recovered memories are authentic
KEY POINTS IN THIS CHAPTER (pages 294-296)
- Memory traces may reflect alterations in neurotransmitter release at specific locations.
Manipulations of hormone levels and protein synthesis can affect memory
- Thompsonʼs research suggest that memory traces may consist of localized neural
circuits. Memories may also depend on long-term potentiation, which is a durable
increase in neural excitability at synapses along a specific neural pathway. Memory
formation may also stimulate neural growth
- In retrograde amnesia, a person loses memory for events prior to the amnesia. In
anterograde amnesia, a person shows memory deficits for events subsequent to the
onset of amnesia. Studies of amnesia and other research suggest that the
hippocampal complex is involved in the consolidation of memories
Chapter 7: Human Memory
In Search of the Memory Trace: The Physiology of Memory
- “memory trace” = physiological bases for memory
The Biochemistry of Memory
- Memory traces may reflect alterations in neurotransmitter release at specific locations.
- sea slugs --> showed that specific forms of leaning in the sea slug result in an
increase of decrease in the release of neurotransmitters by presynaptic neurons
- Manipulations of hormone levels and protein synthesis can affect memory in a variety
of animals
- McGaugh theorized that hormones influence memory storage by modulating activity i
the amygdala and a variety of neurotransmitter systems in the brain
The Neural Circuitry of Memory
- Thompsonʼs research suggest that memories may consist of localized neural circuits.
- Memories may also depend on long-term potentiation (LTP) - a long-lasting increase
in neural excitability at synapses along a specific neural pathway
- Memory formation may also stimulate neural growth
The Anatomy of Memory
- Two basic types of amnesia:
- retrograde amnesia - involves the loss of memories for events that occurred prior to
the onset of amnesia
- anterograde amnesia - involves the loss of memories for events that occur after the
onset of amnesia
--> H.M , had surgery to relieve debilitating epileptic seizures, wiped out most of his
ability to form long term memories - memory loss was originally attributed to the
removal of his hippocampus but now understand that other nearby structures that
were removed also contributed -- now believe that the entire hippocampal region and
the adjacent parahippocampal region are critical for many types of long=term memory
- Studies of amnesia and other research suggest that the hippocampal complex is
involved in the consolidation of memories
- consolidation - a hypothetical process involving the gradual conversion of information
into durable memory codes stored in long-term memory
- theorists influenced by PDP models of memory suggest that the hippocampal area
functions to bind together the individual elements of a memory which are stored in
widely distributed areas of the cortex
KEY POINTS IN THIS CHAPTER (pages 296-300)
- Implicit memory involves unintentional remembering, whereas explicit memory
involves intentional recall. Implicit memory is unconscious, must be accessed
indirectly, and is largely unaffected by amnesia, age, drugs, and the length of the
retention interval
- Declarative memory is memory for facts, while procedural memory is memory for
actions and skills. Theorists suspect that the declarative memory system handles
explicit memory, whereas the procedural memory system handles implicit memory
Chapter 7: Human Memory
- Declarative memory can be subdivided into episodic memory for personal facts, and
semantic memory for general facts. Theorists have also distinguished between
retrospective memory (remembering past events) and prospective memory
(remembering to do thins in the future)
- Our discussion of memory enhances our understanding of why peopleʼs experience of
the world is highly subjective. Work in this area also shows that behaviours is
governed by multiple causes and that psychology is characterized by theoretical
diversity
Are There Multiple Memory Systems?
Implicit versus Explicit Memory
- Implicit memory - apparent when retention is exhibited on a task that does not require
intentional remembering
- unconscious, must be accessed indirectly, and is largely unaffected by amnesia, age,
drugs, and the length of the retention interval
- can be assessed with variations on relearning measures of retention
- Explicit memory - involves intentional recollection of previous experiences
- conscious, accessed directly and can be best assessed with recall or recognition
measured of retention
- Some
Declarative versus Procedural Memory
- Many theorists have suggested that people have separate memory systems for
different kinds of information.
- Most basic division of memory into distinct systems contrasts declarative memory with
nondeclarative or procedural memory
- declarative memory system - handles factual information
- contains recollections of words, definitions, names, dates, faces, events, concepts
and ideas
- nondeclarative/ procedural memory system - houses memory for actions skills,
operations and conditioned responses
- Theorists suspect that the declarative memory system handles explicit memory,
whereas the procedural memory system handles implicit memory
- memory for skills is largely unconscious and performance often deteriorates if people
think too much about what theyʼre doing
- memory for skills doesnʼt decline much over long retention intervals
Semantic versus Episodic Memory
- Declarative memory can be subdivided into:
- episodic memory system - made up of chronological, or temporally dated,
recollections of personal experiences
- semantic memory system - contains general knowledge that is not tied to the time
when the information was learned
Chapter 7: Human Memory
Prospective versus Retrospective
- Prospective memory - involves remembering to perform actions in the future
- Retrospective memory - involves remember events from the past or previously learned
information
- Factors that influence prospective memory
- habitual tasks appear to be easier to remember than infrequent tasks
- event-based tasks involve future actions that should be triggered by a specific cue
- time-based tasks require that an action be performed at a certain time or after a
certain length of time has elapsed
- age