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Memory
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Copyright © Allyn & Bacon 2006
by Pearson Education.
Reproduced by permission of the publisher. Further reproduction
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What is Memory?
• The ability to recall past events, images,
ideas, or previously learned information or
skills
• The storage system that allows a person
to retain and retrieve previously learned
information
Copyright © Allyn & Bacon 2006
How Does the Memory
Process Begin?
The brain as Information Processor
Three Processes
1. Encoding 2. Storage
Information
Sensory
Memory
ShortTerm
Memory
3. Retrieval
LongTerm
Memory
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Encoding
• Organizing sensory information so it can be
processed by the nervous system
•
•
•
Visual
Auditory
Olfactory
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Encoding
1. Attention is important
– Divided attention interferes with encoding
2. Levels of Processing
– Brain encodes information in different
ways or on different levels
– Deeper processing leads to deeper
memory
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Levels of Processing
• All approaches emphasize:
– Importance of encoding
– How information is encoded
– That encoding is flexible
– Effects of cues
– Effects of preconceived biases
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Neuroscience and Encoding
•
•
PET and MRI used to study neurobiological bases
of memory
Two important areas:
a. Prefrontal cortex
• Left: Encoding new memories
• Right: Retrieving old memories
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Neuroscience and Encoding
Two important areas:
a.
b.
•
Prefrontal cortex
Temporal Lobes
temporal lobes active during encoding of
associations
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Types of Memory Storage
Storage is:
– The process of maintaining or keeping
information readily available
– The locations where information is held
• Memory stores
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Types of Memory Storage
A. Sensory Memory
– Performs initial encoding
– Provides brief storage
– Two types
– Iconic Memory
– Echoic Memory
– Information must be transferred to shortterm storage or it will be forgotten
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Types of Memory Storage
B. Short-Term Storage
– Holds information for processing
– Fragile
– Other terms:
• Short term Memory (emphasizes
duration)
• Working Memory (emphasizes active
nature)
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Short-Term Storage
1. Early Research on Short-Term Memory
a. Duration
Information in short-term memory
is available for 20–30 seconds at
most.
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Early Research on Short-Term
Memory
b. Quantity of information stored
• Memory Span
• 5–7 items (George Miller, 1956)
• But what is an item?
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What is an item?
1 4 9 1 6 2 5 3 6 4 9 6 4 8 1 1 0 0
1 4 9 16 25 36 49 64 81 100
Cat orange escalator watch bench
The orange cat sat on the bench watching the
escalator.
• Such groupings are called chunks
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Early Research on Short-Term
Memory
c. Rehearsal
• Process of repeatedly verbalizing or
thinking about information to keep it
active in memory
• Two types:
• Maintenance rehearsal
• Elaborative rehearsal
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Short-Term Storage
2. The Emergence of Working Memory
– Temporarily holds current or recent
information for immediate or short-term
use
– Does not simply store information
– Information is maintained for 20–30
seconds while active processing (e.g.,
rehearsal) takes place
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Types of Memory Storage
C. Long-Term Memory
– Relatively permanent record of memory
– Stored indefinitely
– Capacity seems unlimited
– Several different types
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Long Term Memory
1. Types:
a. Types based on content
i. Procedural memory
ii. Declarative memory
a) Episodic memory
b) Semantic memory
b. Types based on awareness
i. Explicit memory
ii. Implicit memory
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Long Term Memory
2. Practice and Storage
• Two types:
• Massed practice
• Distributed practice
• Found distributed practice best
• Especially for perceptual-motor
skills
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Neuroscience and Storage
• Consolidation
• Process of changing a temporary memory
to a permanent memory
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Retrieval
• The process by which stored information is
recovered from memory
– Depends on
• How retention is measured
• How information is encoded and stored
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Retention: Measures of
Retrieval
Two types of retrieval task:
1. Recall
• Free recall
• Serial recall
• Paired associate
2. Recognition
3. Relearning
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Retrieval
Retrieval Success and Failure:
• Sometimes information is in memory, but is
inaccessible
• Why?
• One reason: poor retrieval cues
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Retrieval
What Facilitates Retrieval?
1. Primacy and Recency Effects
a. Primacy Effect
• Better memory for items at the
beginning of a list
• Better attention
• More time for rehearsal
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Primacy and Recency Effects
b. Recency Effect
– Better memory for items at the end of a list
– Items still in short-term storage
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Primacy and Recency Effects
• Exception:
• Restorff effect
• Occurs when recall is better for a
distinctive item, even if it occurs in the
middle of a list
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What Facilitates Retrieval
2. Imagery
• The creation of a mental picture of a
sensory or perceptual experience
• Important memory aid
• Preserves perceptual information that might
otherwise decay
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Retrieval
Flashbulb Memories
• Detailed memory
for events
surrounding a
dramatic event
• Vivid
• Remembered with
confidence
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Flashbulb Memories
– One theory says this is a special type of
memory for events that are highly
emotional
• Makes them especially accurate
• Other psychologists disagree
– Not a special mechanism
– The emotional component makes these
memories
• More distinctive (affecting encoding)
• More often rehearsed (enhancing retrieval)
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Flashbulb Memories
• Research shows that flashbulb memories
– Are vivid
– Are far from accurate
– Can change over time
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Early Studies
– Found that college students made changes
in stories when recalling them
• Leveling
• Sharpening
• Assimilation
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Early Studies
• Contemporary explanations center on the
reconstructive nature of memory
–
–
Memory formation often relies on a
schema
We can not remember all the details of
an event
• Schemas help fill in the missing details
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Forgetting
Key Causes of Forgetting
1. Decay of Information
• The loss of information from memory
due to disuse and the passage of time
• Disintegration of a physiological
memory trace
2. Interference in Memory
• The suppression of one bit of
information by another
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Interference in Memory
• Two types of interference
a. Proactive interference
• Previously learned information interferes
with the ability to learn new information
b. Retroactive interference
• Newly learned information interferes with
the ability to recall previously learned
information
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Key Causes of Forgetting
3. Interference with Attention
– Likely causes of absentmindedness
• Encoding failure
– Divided attention
• Problem for both encoding and
retrieval
• More of a problem during encoding
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Interference with Attention
• Stroop Effect
–
Read the INK COLOR of the words
below as quickly as you can
YELLOW
RED
BLUE
BLACK
GREEN
RED
BLUE
YELLOW
RED
BLUE
BLACK
GREEN
RED
BLUE
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Forgetting
Special Types of Forgetting
1. Eyewitness Testimony
• Both jurors and judges place high
confidence in eyewitnesses
– However, research shows
eyewitnesses are often inaccurate
– Loftus’ (1975, 1979) research
» Demonstrated memory distortion
may be caused by the wording of a
question
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Eyewitness Testimony
• Demonstrates the misinformation effect
• High motivation to remember an event can
actually distort it
• Accuracy and confidence are uncorrelated
– Speed of identification is a better
indicator of accuracy than confidence
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Special Types of Forgetting
2. Motivated Forgetting
– Occurs when frightening, traumatic events
are forgotten because people want to
forget them
– First suggested by Freud (1933)
• Believed such memory loss occurred
through repression
– Underlies the debate on recovered
memory
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