Memory Processes
Chapter 6
Outline
1. Encoding and Transfer of Information
2. Retrieval
3. Processes of Forgetting and Memory
Distortion
4. The Constructive Nature of Memory
1. Encoding and Transfer of
Information
•
1. Forms of Encoding
Short-Term Storage
Acoustic Encoding
– Participants were presented with series of
six letters in a serial-recall task
– Errors – participants substituted letters that
sounded like the correct letters (e.g. B for P)
– Short-term memory relies primarily on an
acoustic rather than semantic or visual code
1. Encoding and Transfer of
Information
•
1. Forms of Encoding
Short-Term Storage
Semantic Encoding (by meanings of words)
–
•
Although encoding in short-term memory appears to
be primarily acoustic, there may be some secondary
semantic encoding as well
Visual Encoding
–
We sometimes temporarily encode information
visually as well, although visual encoding appears
to be more fleeting and vulnerable to decay than
acoustic encoding
1. Encoding and Transfer of
Information
•
1. Forms of Encoding
Long-Term Storage
Semantic Encoding
– Most information stored in long-term
memory is primarily semantically encoded
– Evidence
•
•
In recognition tasks participants make more
errors when distracters are semantically related
to target words
We have tendency to remember words by
clustering them into categories (e.g. animals)
1. Encoding and Transfer of
Information
•
1. Forms of Encoding
Long-Term Storage
Visual Encoding
– We tend to cluster items into categories
according to their visual similarities
•
Acoustic Encoding
– Sometimes (even though rarely) we use
acoustic encoding too
1. Encoding and Transfer of
Information
2. Transfer of Information from Short-Term
Memory to Long-Term Memory
• Basic Concepts
– Consolidation
• Process of integrating new information into stored
information
– Metamemory Strategies
• Based on reflecting on our own memory processes
wit a view to improving our memory
1. Encoding and Transfer of
Information
2. Transfer of Information from Short-Term Memory
to Long-Term Memory
• Rehearsal
– Repeated recitation of an item
– To move information into long-term memory, an
individual must engage in elaborative rehearsal, in
which the person meaningfully integrates the items
into what the person already knows
– Maintenance rehearsal – the person simply
repetitiously rehearses the items to be repeated,
temporarily maintains information in short-term
memory without transferring it to long-term memory
1. Encoding and Transfer of
Information
2. Transfer of Information from Short-Term Memory
to Long-Term Memory
• Spacing effect
– People tend to remember information longer when they
acquire it via distributed practice (i.e., various sessions
spaced over time) rather than via massed practice
(session crammed together all at once)
– A good night’s sleep, which includes plenty of REM
stage sleep, aids in memory consolidation
– Benefits of distributed practice seem to occur because
we have a relatively rapid learning system in the
hippocampus that becomes activated during REM
sleep
1. Encoding and Transfer of
Information
2. Transfer of Information from Short-Term Memory
to Long-Term Memory
Mnemonic devices
• Specific techniques to help you memorize lists of
words by adding meaning to otherwise
meaningless lists of items
1. Categorical clustering
– One organizes a list of items into a set of categories
(e.g. fruits, vegetables,…)
2. Interactive images
– One imagines the objects represented by words one
has to remember interacting with each other in some
active way
1. Encoding and Transfer of
Information
2. Transfer of Information from Short-Term Memory
to Long-Term Memory
Mnemonic devices (cont.)
3. Pegword system
– One associates each word with a word on a previously
memorized list and forms and interactive image
between the two words (e.g. “one is a bun,” “two is a
shoe” – imagining an apple between two bunds a sock
stuffed inside a shoe)
4. Method of loci
– One visualizes walking around an area with distinctive
landmarks and one then links the various landmarks to
specific items to be remembered (e.g. a strangelooking house with a sock on top of the house in place
of the chimney)
1. Encoding and Transfer of
Information
2. Transfer of Information from Short-Term
Memory to Long-Term Memory
Mnemonic devices (cont.)
5. Acronyms
– One devises a word or expression in which each of its
letters stands for a certain other word or concept (e.g. UK)
6. Acrostics
– One forms a sentence rather than a single word to help
one remember new words (e.g. “every good does fine” to
recall names of notes in music)
1. Encoding and Transfer of
Information
2. Transfer of Information from Short-Term
Memory to Long-Term Memory
Mnemonic devices (cont.)
7. Keyword system
– One forms an interactive image that links the sound
and meaning of a foreign word with the sound and
meaning of a familiar word (e.g. libro (Spanish) with
liberty and think of the Statue of Liberty holding up a
large book)
2. Retrieval
1. Retrieval from Short-Term Memory
• Saul Sternberg (1966)
– Wondered whether items are retrieved all at
once (parallel processing) or sequentially
(serial processing)
– See his paradigm on the next slide
?
Memorize the following list of numbers:
6, 3, 8, 2, 7, 5
Was 8 on the list?
2. Retrieval
1. Retrieval from Short-Term Memory
• Saul Sternberg (1966)
– Parallel processing
• Simultaneous handling of multiple operations
• Response times should be the same, regardless of
the size of the set of items, because all
comparisons would be done at once
– Serial processing
• Operations being done one after another
• It should take longer to retrieve four digits than to
retrieve two digits
2. Retrieval
1. Retrieval from Short-Term Memory
• Saul Sternberg (1966)
– Serial processing
• Exhaustive serial processing – the participant
always checks the test digit against all digits in the
set, even if a mach were found partway through
the list
• Self-terminating serial processing – the participant
would check the test digit against only those digits
needed to make a response
2. Retrieval
1. Retrieval from Short-Term Memory
• Saul Sternberg (1966)
– Results
• Response times increased linearly with set size but
were the same regardless of serial position
• It indicates that serial exhaustive model seems to
be right
2. Retrieval
2. Retrieval from Long-Term Memory
• Categorization dramatically affects retrieval
– Cued-recall (participants tested category by category)
is far better than free-recall (participants recalled as
many words as they could regardless of the category)
– Participants given hierarchical presentation of
categories of items recalled 65% of words, compared
with recall of just 19% by participants given the words
in random order
3. Processes of Forgetting and
Memory Distortion
1. Interference theory
• Competing information causes us to forget
something
• “Brown-Peterson” paradigm (Brown and
Peterson, 1959)
– Participants had to recall trigrams (strings of three
letters) at intervals of 3, 6, 9, 12, 15, or 18 seconds
after the presentation of the last letter
– After oral presentation of each trigram, participants
were asked to count backward by threes from a threedigit number spoken immediately after the trigram
3. Processes of Forgetting and
Memory Distortion
1. Interference theory
• Two kinds of interference
– Retroactive interference
• Caused by activity occurring after we learn something but
before we are asked to recall that thing
• The interference in the Brown-Peterson task appears to be
retroactive because counting backward by threes occurs
after learning of the trigram and interferes with our ability to
remember information we learned previously
– Proactive interference
• The interference material occurs before, rather than after,
learning of the to-be-remembered material
• In the Brown-Peterson task the trigrams learned earlier
interfered with participants’ ability to remember later trigrams
?
Say the following list of words once to
yourself, and then, immediately thereafter,
try to recall all the words, in any order,
without looking back at them:
Table, cloud, book, tree, shirt, cat, light,
bench, chalk, flower, watch, bat, rug, soap,
pillow
3. Processes of Forgetting and
Memory Distortion
Recency and primacy effects
• Recency effect
– Superior recall of words at and near the end of the list
– Words at the end are subject to proactive but not
retroactive interference
• Primacy effect
– Superior recall of words at and near the beginning of
the list
– Words at the beginning of the list are subject to
retroactive but not proactive interference
– Words in the middle of the list are subject to both
types of interference, therefore, recall is poorest in the
middle of the list
3. Processes of Forgetting and
Memory Distortion
2. Decay theory
• Information is forgotten because of
gradual disappearance, rather than
displacement, of the memory trace
• It is exceedingly difficult to test
– Preventing participants from rehearsing and
ruling out the interference at the same time is
difficult
– Possibility: visually present participants with
words and then engage them in a tonedetection task
4. The Constructive Nature of
Memory
• Memory retrieval is not just reconstructive
– Involving the use of various strategies for retrieving
the original memory traces of our experiences and
then rebuilding the original experiences as a basis for
retrieval
• Memory retrieval is also constructive
– Prior experience affects how we recall things and
what we actually recall
• Participants read an ambiguous passage that could be
interpreted meaningfully as being either about watching a
peace march or about a space trip
• Participants omitted different details, depending on what they
thought the passage was about
4. The Constructive Nature of
Memory
Autobiographical memory
• Refers to memory of an individual’s history
• It is constructive
– One does not remember exactly what has
happened
– Rather, one remembers one’s construction or
reconstruction of what happened
– It is differentially good for different periods of
time
4. The Constructive Nature of
Memory
Memory Distortions
• Seven specific ways in which distortions occur:
– Transience: memory fades quickly
– Absent-mindedness: people sometimes brush their
teeth after already having brushed them
– Blocking: people have something that they know they
should remember, but they can’t
– Misattribution: People often cannot remember where
they heard what they heard
– Suggestibility: people are susceptible to suggestion
– Bias: People often are biased in their recall (e.g. pain)
– Persistence: People sometimes remember personally
significant but inconsequential things (e.g. single
failure on an exam)
4. The Constructive Nature of
Memory
Eyewitness Testimony
– Experiments have shown people’s great
susceptibility to distortion in eyewitness
accounts
– Problems with wrongful conviction when using
eyewitness testimony
– Lineups can lead to faulty conclusions
– It is clearly suspect in children because they
are highly susceptible to suggestive
questioning
4. The Constructive Nature of
Memory
• Repressed Memories
– No compelling evidence points to the existence of
such memories
• Context Effects on Encoding and Retrieval
– Flashbulb memory
• Memory of an event so powerful that the person remembers
the event as vividly as if it were preserved on film
– We remember better event with significant emotional
intensity
– When information is encoded in various contexts, the
information also seems to be retrieved more readily in
various contexts