Download Chapter 7: Human Memory

Chapter 7: Human Memory
Human Memory: Basic Questions
• How does information get into memory?
• How is information maintained in memory?
• How is information pulled back out of
memory?
Figure 7.2 Three key processes in memory
Encoding: Getting Information Into Memory
• Attention- focusing awareness on a narrowed
range of stimuli or events.
• Divided attention- can have a negative impact on
the performance of quite a variety of tasks.
– When participants are forced to divide their
attention between memory encoding and some
other task, large reductions in memory
performance is seen.
Encoding: Getting Information into Memory
• Levels of processing
– Incoming information processed at different levels
– Theory proposes that deeper levels of processing
result in longer-lasting memory codes
– Encoding levels:
• Structural = shallow-emphasizes the physical
structure of the stimuli
• Phonemic = intermediate-emphasizes what a
word sounds like
• Semantic = deep-emphasizes the meaning of
verbal input
Figure 7.3 Levels-of-processing theory
Enriching Encoding to Improve Memory
• Elaboration = linking a stimulus to other information
at the time of encoding
– The additional associations created usually help
people remember information
– Often consists of thinking of examples that illustrate
an idea
• Visual Imagery = creation of visual images to
represent words to be remembered
– Easier to form images for concrete objects than of
abstract concepts
• Dual-coding theory- memory is enhanced by forming
both semantic and visual codes, since either can lead
to recall.
Storage: Maintaining Information in Memory
• Information storage in computers ~ information
storage in human memory
• Information-processing theories- subdivide memory
into 3 different stores
– Sensory- preserves information in its original sensory
form for a brief time, usually only a fraction of a
second (afterimage)
– Short-term- a limited-capacity store that can maintain
unrehearsed information for up to about 20 seconds
– Long-term- an unlimited capacity store that can hold
information over lengthy periods of time
Figure 7.6 The Atkinson and Schiffrin model of memory storage
Short Term Memory (STM)
• Limited duration – about 20 seconds without
rehearsal
– Rehearsal – the process of repetitively verbalizing
or thinking about the information (keeping it in use)
• Limited capacity – people can only recall about 7
items on tasks that required them to remember
unfamiliar material (magical number 7 plus or minus 2)
– When STM is filled to capacity, the insertion of new
information often displaces some of the current
information.
– Chunking – grouping familiar stimuli for storage as
a single unit (phone numbers)
• Helps increase the capacity of your STM
Short-Term Memory as “Working Memory”
• STM not limited to phonemic encoding
• Loss of information not only due to decay
• Baddeley (1986) – 4 components of working memory
– Phonological rehearsal loop- is at work when you use
recitation to temporarily hold onto a phone number
– Visuospatial sketchpad- allows temporary holding and
manipulation of visual images
– Central executive system-handles the limited amount
of information juggled at one time as people in
reasoning and decision making
– Episodic buffer- temporary limited capacity store that
allows the various components of working memory to
integrate information (serves as an interface between
Figure 7.7 Short-term memory as working memory
Long-Term Memory
• Unlimited capacity- our memory store never
gets full.
• Flashbulb memories- unusually vivid and
detailed recollections of momentous events
– the only reason we forget is that we aren’t
able to access information that is still in
LTM
• How is knowledge represented and organized
in memory?
– Schemas and Scripts
– Semantic Networks
– Connectionist Networks and PDP Models
Organization in Long-Term Memory
• Schemas- an organized cluster of knowledge about a
particular object or event abstracted from previous
experience with the object or event
– script is a particular type of schema, organizing what a
person knows about common activities, for example going to
a restaurant
• Semantic Networks- consists of nodes representing
concepts, joined together by pathways that link related
concepts
– explains why thinking of butter makes bread easier to
remember
• Connectionist Networks- assume that cognitive processes
depend on patterns of activation in highly interconnected
computational networks that resemble neural networks
– specific memories correspond to specific patterns of
Retrieval: Getting Information
Out of Memory
• The tip-of-the-tongue phenomenon – the temporary
inability to remember something you know,
accompanied by a feeling that it’s just out of reach.
(failure in retrieval)
– Retrieval cues- stimuli that help gain access to
memories (hints, partial recollections)
• Reinstating the context through context cues
– Trying to recall an event by putting yourself back in
the context in which it occurred.
Retrieval: Getting Information
Out of Memory
• Reconstructing memories-sketchy reconstructions
of the past that may be distorted and cause the
misinformation effect
– A recall of an event that was witnessed but altered
due to the introduction of misleading postevent
information
• Source monitoring error- an error that occurs when
a memory derived from one source is attributed to
another source
– A crucial part of memory retrieval that contributes to
many of the mistakes that people make in
reconstructing their experiences
Forgetting: When Memory Lapses
• Ebbinghaus’s Forgetting Curve- graphs retention
and forgetting over time
– Showed that most forgetting occurs very rapidly
after learning something.
• Retention- the proportion of material retained
(remembered). Can assessed with measures of
forgetting
– Recall-requires participants to reproduce information on
their own without cues
– Recognition- requires participants to select previously
learned information from an array of options
– Relearning- requires a participant to memorize
information a second time to determine how much time
or effort is saved by having learned before
Figure 7.10 Ebbinghaus’ forgetting curve for nonsense syllables
Why We Forget
• Ineffective Encoding-the information may have never
been inserted in the memory in the first place
– Pseudoforgetting- you can’t remember something
you never learned
• Decay- forgetting occurs because memory traces fade
with time
• Interference-people forget information because of
competition from other material
– Proactive- occurs when previously learned
information interferes with the retention of new
information
– Retroactive- occurs when new information impairs
the retention of previously learned information
Why We Forget
• Retrieval failure- may occur when a
mismatch exists between retrieval cues and
the encoding of the information to be recalled
Figure 7.11 Effects of interference
Figure 7.12 Retroactive and proactive interference
Retrieval Failure
• May occur when a mismatch exists between retrieval
cues and the encoding of the information to be
recalled
• Encoding Specificity-sometimes we are unable to
retrieve information because the retrieval cues do not
correspond very well to memory cues.
• Transfer-Appropriate Processing-occurs when the
initial processing of information is similar to the kind of
processing that is required by the measure of
retention.
Retrieval Failure
• Repression-the motivated forgetting of material,
especially anxiety-provoking memories.
– Authenticity of repressed memories?
• sharply debated because experiments show that it is
relatively easy to create very real-seeming false
memories.
– Memory illusions-false memories that can be reliably
created in normal, healthy participants in minutes.
– Controversy
• Evidence suggests that sometimes therapists have
unwittingly produced false memories in their clients,
but it is likely that at least some recovered memories
are accurate.
•
http://www.youtube.com/watch?v=23Pum-7-pyM&feature=BFa&list=PLF9A174B24892CB44&index=6
Figure 7.14 The prevalence of false memories observed by Roediger and McDermott (1995)
The Physiology of Memory
• Anatomy-many brain structures have been shown to
be important in memory.
– Anterograde (for subsequent events)and Retrograde
Amnesia (for prior events)
• Hippocampus
• Medial temporal lobe memory system
• Neural circuitry-memories appear to depend on
localized neural circuits in the brain
– reusable pathways in the brain that may be specific
for specific memories
• Biochemistry
– Hormonal changes which may modulate activity in a
variety of neurotransmitter systems.
– Protein synthesis-has also been shown to be
necessary for memory formation.
Figure 7.16 The anatomy of memory
Systems and Types of Memory
• Two memory systems:
• Declarative- handles recall of factual
information (names, dates, events, ideas)
• Nondeclarative- handles recall of actions,
skills, and operations (riding a bike or typing)
Declarative Memory System:
Type of memory
Semantic vs. Episodic
• Semantic memory system
contains general
knowledge that is not
temporally dated
• Episodic memory system
handles temporally dated
recollections of personal
experiences
Prospective vs.
Retrospective
• Prospective memory
involves remembering to
perform actions in the
future
• Retrospective memory
involves remembering
events from the past or
previously learned
information
• http://www.youtube.com/watch
?v=rSzPn9rsPcY&NR=1
Figure 7.17 Theories of independent memory systems
Figure 7.18 Retrospective versus prospective memory
http://www.youtube.com/watch?v=TausqSK9p9k&feature=related