Transcript Ch 6 LTM structure

Human Cognitive
Processes: psyc 345
Ch. 6 Long-term memory
Takashi Yamauchi
© Takashi Yamauchi (Dept. of Psychology, Texas A&M University)
• (Q1) Is short-term memory and long-term
memory anatomically and behaviorally
separable? If so, how?
• (Q2) Which part of the brain is used for
long-term memory, and how do we store
long-term memory?
• (Q3) Are there different kinds of long term
memory systems?
• (Q1) Is short-term memory and long-term
memory anatomically and behaviorally
separable? If so, how?
• (Q2) Which part of the brain is used for
long-term memory, and how do we store
long-term memory?
• STM vs. LTM
– There are clear distinctions between STM and LTM.
– STM and LTM interact constantly.
• Demonstration:
– CogLab
• Serial position
memory is better for words presented at the beginning of
the list (primacy effect) and at the end (recency effect)
Fig. 6-5, p. 182
The dashed curve
occurred when the
words were presented
more slowly
no recency effect
occurs if the memory
test is delayed for 30
seconds (dashed line).
Fig. 6-6, p. 183
What does this tell?
• Primacy effect
– Words are rehearsed during presentation of
the list, so they get into LTM
• Recency effect
– Words are still in STM
Distinguishing STM and LTM:
Neuropsychological evidence
• K. F. (described by Warrington et al.)
– STM  Impaired, LTM  OK
• A left posterior temporal lesion
– This resulted in an almost total inability to
repeat verbal stimuli (digits, letters, words,
and sentences)
Memory
• H. M.
– his hippocampus is surgically removed.
• Impaired:
– H. M. cannot retain information about events
that happened after the operation.
• Intact
– intelligence (IQ), attention, concentration,
language and motivation levels were intact.
– good memories about several weeks before
the operation.
Hippocampus
Selectivity of memory loss
• H. M.
– before the operation
– remembered which elementary school he
went, the names of friends in his high school
days, TV programs he saw when he was a
child.
– Had no idea about what he did, whom he met,
what he saw, and what he talked last months,
last week, or even a few hours ago.
H.M.
• Memory dissociation
–
–
–
–
–
H.M.’s IQ 118
Language comprehension  normal
Motor learning  normal
Problem solving and practice  normal
H.M. had good memory about the events and
incidents he experienced before the surgery.
– H.M. hardly remember what happened to him after
the surgery
H.M. (continued)
• H.M. was severely impaired in one type of
memory,
• such as the memory about specific events,
– but his memory about motor skills and other
learning is intact.
Mirror-reversed word triad
• (Q3) Are there different kinds of long term
memory systems?
• Organization of LTM
Declarative (explicit) vs. Implicit
memory
• Declarative (explicit) memory
– Is our conscious recollection of events or facts
we have learned
• Implicit memory
– Memory without conscious awareness
• Episodic: memory for personal
events
– Episodic involves mental time travel
– You can trace down the time frame
of your episodic experience.
• Semantic: facts and knowledge
– Semantic memory does not involve
mental time travel
The separation of episodic &
semantic memories
• Episodic can be lost, leaving only
semantic
– Acquiring knowledge may start as
episodic but then “fade” to semantic
• Semantic memory can be lost, while
episodic memory is intact.
– A brain damaged patient knows what
she did yesterday, or 10 days ago but
don’t remember meanings of words.
Separate brain activation for
episodic and semantic memory
• Fig. 6.8
Blue areas are associated with semantic
memory
Connection between Episodic
& Semantic Memories
• Semantic Memory can be enhanced
if associated with episodic M.
– Personal semantic memory: semantic
memories that have personal
significance
• Episodic Memory can be enhanced if
associated with semantic M.
– Extracting meaning (e.g., story)
enhance our memory.
Implicit memory
• Implicit memory
– Memory without conscious awareness
• CogLab
• Implicit learning
Neuropsychological evidence
• Movie:
• DVD: How does your memory work?
(chapter 3; 7:09)
Implicit or Explicit Memory
Tasks
• Explicit memory tasks
– Involves conscious recollection
– Participant knows they are trying to retrieve
information from their memory
• Implicit memory tasks
– Require participants to complete a task
– The completion of the task indirectly indicates
memory
implicit memory tasks
• Mirror tracing
• Mirror reversed reading
• Identifying degraded words
• http://www.psywww.com/intropsych/ch06_me
mory/implicit_vs_explicit_memory.html
Tulving, E., Schacter, D. L.,
Stark, H. A. (1982).
• Priming and implicit memory
• Test implicit memory and explicit memory
– Stimuli:
• 96 words
– Design:
• 3 phases: Learning phase & test phase (1hr)
• & test phase (7 days later)
Tasks
• Phase I (Learning)
– Ss studied 96 words (5sec/word)
– Ss were told that they would be tested with
their recognition memory.
– Ss could study the words in whatever way
they like.
Fig. 6-10, p. 194
Learning a new skill: mirrorreverse reading
Mirror-tracing
Reading degraded
words
Warrington (1968)
• 5 patients with Korsakoff’s syndrome
–  deficit in declarative memory
• Give them incomplete pictures and let
them learn how to identify the fragmented
pictures.
Show (a), and then (b), (c),.. so on until they were able to identify the picture
Fig. 6-11, p. 194
Fig. 6-12, p. 195
Implicit memory in everyday
experience
• Mere exposure effect / propaganda effect
• You form a positive feeling to things that
you experienced before.
Perfect & Askew (1994)
• Participants scanned ads in a magazine.
• They rated how appealing the ads were.
• Results: Participants gave higher ratings to the
ones they had been exposed to than to the ads
they had never seen.
• This happened even when they recognized
2.4% of the original 25 ads.
• Masked priming: demonstration
• http://www.u.arizona.edu/~kforster/priming/ind
ex.htm
H.M.
• Memory dissociation
–
–
–
–
–
H.M.’s IQ 118
Language comprehension  normal
Motor learning  normal
Problem solving and practice  normal
H.M. had good memory about the events and
incidents he experienced before the surgery.
– H.M. hardly remember what happened to him after
the surgery
Hippocampus
Initial state
Goal state
• Tower of Hanoi solution
• http://www.youtube.com/watch?v=aGlt2GDC8c
• H. M got better at doing the Tower of
Hanoi game even though he did not
remember at all about his previous trials.