Transcript Chapter 7: Human Memory

Chapter 7: Human Memory
Figure 7.2 Three key processes in memory
Process of Remembering
 Encoding
– Transforming information into a form that can be stored
in memory
 Storage
– The process of keeping or maintaining information in
memory
 Retrieval
– Bringing to mind information that has been stored in
memory
Copyright © 2011
Encoding: Getting Information Into Memory
• The role of attention
• Focusing awareness
• Divided attention
Encoding: Getting Information into Memory
• The role of attention
• Levels of processing
– Incoming information processed at different
levels
– Deeper processing = longer lasting
memory codes
– Encoding levels:
• Structural = shallow
• Phonemic = intermediate
• Semantic = deep
Figure 7.3 Levels-of-processing theory
Enriching Encoding
• Elaboration = linking a stimulus to other
information at the time of encoding
– Thinking of examples
• Visual Imagery = creation of visual images to
represent words to be remembered
– Easier for concrete objects: Dual-coding
theory
Storage: Maintaining Information in Memory
• Analogy: information storage in computers ~
information storage in human memory
• Information-processing theories
– Subdivide memory into three different
stores
• Sensory, Short-term, Long-term
Three Memory Systems
Copyright © 2011
Sensory Memory
• Brief preservation of information in original
sensory form
• Auditory/Visual – approximately ¼ second
•LO 6.2 What are the characteristics of sensory memory?
Sensory Memory
SENSORY
MEMORY
• Temporary storage for
sensory information
• Capacity:
• Large
• Duration:
• Visual: fraction of a
second
• Auditory: 2 seconds
Short-term or Working Memory
Sensory
Input
Sensory
Memory
Attention Working or
Short-term
Memory
Short-term Memory
• Function—conscious processing of
information
– where information is actively worked on
• Capacity—limited (holds 7 +/- 2 items)
• Duration—brief storage (about 30 seconds)
Sensory
Input
Sensory
Memory
Attention Working or
Short-term
Memory
Short Term Memory (STM)
• Limited duration – about 20 seconds
without rehearsal
– Rehearsal – the process of repetitively
verbalizing or thinking about the
information
• Limited capacity – magical number 7 plus
or minus 2
– Chunking – grouping familiar stimuli for
storage as a single unit
Chunking
• Grouping small bits of information
into larger units of information
– expands working memory load
• Which is easier to remember?
– 4 8 3 7 9 2 5 1 6
– 483 792 516
Long-term Memory
• Once information passes from sensory to
working memory, it can be encoded into
long-term memory
Maintenance Rehearsal
Sensory
Input
Sensory
Memory
Attention
Encoding
Long-term
Working or
Memory
Short-term
Memory Retrieval
Long-Term Memory
• Encoding—process that controls movement from
working to long-term memory store
• Retrieval—process that controls flow of information
from long-term to working memory store
Maintenance Rehearsal
Sensory
Input
Sensory
Memory
Attention
Encoding
Long-term
Working or
Memory
Short-term
Memory Retrieval
Types of Long-term Memory
• Explicit memory—memory with
awareness; information can be
consciously recollected; also called
declarative memory
• Implicit memory—memory without
awareness; memory that affects behavior
but cannot consciously be recalled; also
called nondeclarative memory
Figure 7.17 Theories of independent memory systems
Procedural Memory
• Memory that enables you to perform specific
learned skills or habitual responses
• Examples:
– Riding a bike
– Using the stickshift while driving
– Tying your shoe laces
Q: Why are these procedural memories implicit?
A: You don’t have to consciously remember the steps
involved in these actions to perform them
– Try to explain to someone how to tie a shoelace
Three Types of Memory Tasks
 Recall
– Producing required information by
searching memory
– Retrieval cue
 Any stimulus or bit of information that
aids in retrieval
 Recognition
– Identifying material as familiar or as
having been encountered before
– Only requires that you recognize it, not
recall all the information
 Relearning
– Retention expressed as the percentage
of time saved when material is relearned
Flashbulb Memory
The recall of very specific images or details
surrounding a vivid, rare, or significant personal
event; details may or may not be accurate (e.g.,
9/11, wedding day, high school graduation)
Encoding Specificity
– When conditions of retrieval are similar to
conditions of encoding, retrieval is more
likely to be successful
– You are more likely to remember things if
the conditions under which you recall them
are similar to the conditions under which
you learned them
Serial Position Effect
For information learned in a sequence, recall is better for the beginning
and ending items than for the middle items in the sequence.
 Primacy effect
– Tendency to recall the first items in a sequence more readily
than the middle items
 Recency effect
– Tendency to recall the last items in a sequence more readily
than those in the middle
 Poorer recall of information in the middle of a series because it is no
longer in short-term memory
 Serial position effect supports notion of separate systems for shortand long-term memory
Copyright © 2011
Retrieval: Getting Information
Out of Memory
• The tip-of-the-tongue phenomenon – a failure
in retrieval
– Retrieval cues
• Reinstating the context
– Context cues
• Reconstructing memories
– Misinformation effect
• Source monitoring
Retrieval Failure
• Encoding Specificity
• Transfer-Appropriate Processing
• Repression
– Authenticity of repressed memories?
– Memory illusions
– Controversy
Memory Construction and Distortion
• Memories are not passive, complete records
like photographs or video recordings; they are
constructed and reconstructed.
• Schemas, which represent our general
knowledge and beliefs, can affect memory at
both encoding and retrieval, assisting
memory but sometimes distorting it.
Reconstruction
When people recall an
event, such as a car
accident, they are
actually reconstructing
it from memory by
piecing together bits of
information that may or
may not be totally
accurate.
Copyright © 2011
The Forgetting Curve
Hermann Ebbinghaus
first began to study
forgetting by using
nonsense syllables
Nonsense syllables
are three-letter
combinations that
look like words but
are meaningless
(ROH, KUF)
Why We Forget
• Ineffective Encoding
• Decay
• Interference
– Proactive
– Retroactive
• Retrieval failure
• Repression
– Authenticity of repressed memories?
– Memory illusions
– Controversy
Motivated Forgetting
Undesired memory is held back from
awareness
Suppression—conscious forgetting
Repression—unconscious forgetting
(Freudian)
Figure 7.12 Retroactive and proactive interference
Figure 7.11 Effects of interference
The Physiology of Memory
• Anatomy
– Anterograde and Retrograde Amnesia
• Hippocampus
• Medial temporal lobe memory system
• Neural circuitry
– Localized neural circuits
• Biochemistry
– Hormones modulating neurotransmitter
systems
– Protein synthesis
How does the brain store our
memories?
• Experience modifies the brain’s neural
network; increase activity in a particular
neural pathway strengthens the
interconnections.
• Long-term potentiation-prolonged
strengthening of neural firing. Provides the
neural basis for learning and memory.
Figure 6.11 Brain Structures Involved in Human Memory Shown here are
some of the key brain structures involved in encoding and storing memories.
Creating New Synaptic Connections Forming new memories involves strengthening
existing synaptic connections and creating new synaptic connections between neurons in
the brain. Neuroscientist Michael Colicos and his colleagues at the University of California–
San Diego (2001) photographed structural changes in a single hippocampus neuron that
occurred in response to repeated electrical stimulation. The spidery blue lines in the photo
are physical changesin the neuron’s structure that represent the first steps toward the
formation of new synaptic connections with other neurons.
The posterior (rear) hippocampus of an
experienced London taxi driver, shown in red in the
MRI scan on the left, is significantly larger than the
posterior hippocampus of a research participant
who was not a taxi driver, shown in red in the scan
on the right.
Copyright © 2011
Gradually Losing the
Ability to Remember
Dementia: Progressive deterioration and impairment of
memory, reasoning, and other cognitive functions
occurring as the result of a disease or a condition
Alzheimer’s disease (AD): A progressive disease that
destroys the brain’s neurons, gradually impairing
memory, thinking, language, and other cognitive
functions, resulting in the complete inability to care
for oneself; the most common form of dementia
Figure 7.18 Retrospective versus prospective memory
Strategies for Boosting Memory
•
•
•
•
Focus attention
Commit the time
Space study sessions
Organize the
information
• Elaborate on the
material
• Use visual imagery
• Use a mnemonic
device
• Explain it to a friend
• Reduce interference
within a topic
• Counteract the serial
position effect
• Use contextual clues
• Sleep on it
• Forget the ginkgo
biloba
Improve Your Memory
• Study repeatedly to boost recall
• Spend more time rehearsing or actively
pondering material
• Make material personally meaningful
• Use mnemonic devices
– associate with peg words- something
already stored
– make up story
– chunk-acronyms
Improve Your Memory
• Activate retrieval cues- mentally recreate
situation and mood
• Recall events while they are fresh- write
down before interference
• Minimize interference
• Test your own knowledge
– rehearse
– determine what you do not yet
know