Transcript Human Cognitive Processes

Human Cognitive
Processes: psyc 345
Ch. 7 Long-term memory:
Encoding and retrieval
Takashi Yamauchi
© Takashi Yamauchi (Dept. of Psychology, Texas A&M University)
• (Q1) What is the best way to store
information in long-term memory?
• (Q2) What are some techniques to help us
get information out of LTM when we need
it?
• (Q3) How is it possible that a lifetime of
experiences and accumulated knowledge
can be stored in neurons?
• (Q1) What is the best way to store
information in long-term memory?
Encoding
• What encoding strategy enhances long
term memory?
• http://www.youtube.com/watch?v=0J9J_yD41k&NR=1
Level-of-processing theory
• Memory depends on depth of processing
• Deep processing vs. shallow processing
– Focusing on an item’s meaning and relating it
to something else.
• Shallow processing
– Little attention to meaning, attention to
physical features to items. Rote memory
Craik & Tulving (1975)
• Experiments:
– Levels of processing and remembering
– Deep processing helps
• (Processing semantic information helps)
• CogLab: level of processing
Experiment:
• Tasks:
– Subjects were shown words one by one on a
screen.
– They carried out one of 3 different tasks.
• Task1: Capital letters?
• low semantic involvement
– Ss judged whether the word presented on the
screen is printed with capital letters or not.
– TRAIN  yes
– Table  no
• Task2: Rhyme?
– In another trial, Ss were shown a word (e.g., TRAIIN)
and judged whether or not the word rhymed with a
word (e.g., BRAIN).
•
•
•
•
Train  brain - yes
Crate  weight  yes
Table  cable  yes
Book –> note  no
• Task 3: Fill in the blanks
– Ss judged whether or not the word shown first
fitted a particular sentence.
– E.g., “friend” was shown, and a sentence
• “He met a
in the street” was shown.
• The answer is “yes”.
Different levels of depth
• Task 1 < Task 2 < Task 3
Memory test (recognition):
• After Ss carried out these tasks, then a list
of 80 words was given.
– In the list, 40 words appeared during the first
phase.
– 40 words were new words that did not appear
in the first phase.
• Ss indicated the words that they
remember from the first phrase.
These tasks differ in the level of
processing.
Craik & Tulving 1975
Answer
Question
Yes
No
Structural
Is the word in capital letters?
TABLE
table
Phonemic
Does the word rhyme with WEIGHT
crate
MARKET
Category
Is the word a type of fish?
SHARK
heaven
Sentence
Would the word fit the sentence:
FRIEND
cloud
"He met a
in the street?"
Processing semantic
information
• The three tasks differed in the degree to
which semantic information was
processed.
• Fill in blanks > Rhyme > Capital letter
• Level of processing: (2:22)
– http://www.youtube.com/watch?v=0J9J_yD41k&NR=1
Additional factors that aid encoding
Fig. 6-18, p. 206
• Creating connections
– Visualizing study items.
– Relating study items to yourself.
– Generating study items by yourself
• Bower & Winzenz (1970)
– Ss received a list of 15 pairs, (boat, tree)…
– One group were told to just repeat the words.
– Another group were told to form mental
pictures
•Ss in the mental picture group were
able to recall twice as many words as
the Ss in the repeat group.
Self-referencing effect
• Ss received a word list.
– Sad, positive, overwhelming, sly, shy,
happy,…
– They answered yes-no questions
• happy
– Printed in small case? (physical
characteristics)
• snappy
– Rhymes with happy? (rhyming)
• upbeat
– Means the same as happy? (meaning)
• happy
– Describe you? (self-reference)
• (Q2) What are some techniques to help us
get information out of LTM when we need
it?
Retrieving information from LTM
• What are effective ways of encoding and
retrieving?
• Using retrieval cues
• Retrieval cues are like “hints” that are
useful for retrieving memories.
Cued recall
• Mantyla (1986)
• Ss received a list of 600 nouns
– (e.g., banana, freedom, tree, …)
• During learning, Ss wrote down three
words and associated the words with each
noun.
– E.g., banana  yellow, bunches and edible.
Cued recall
• Ss were given a surprise memory test.
• Ss were presented with the three words
they had created.
– e.g., yellow, bunches and edible
• 90% of the 600 words were recalled
correctly.
• Another group of participants:
– Did not create their own cues
– But they were given cues that were produced
by someone else
• E.g., banana  yellow, bunches and edible.
• 55% of the words were recalled.
Fig. 6-28, p. 217
• Creating your own retrieval cues during
encoding REALLY helps
Encoding specificity
• How are encoding and retrieval related?
• Encoding specificity theory
– Memory retrieval is effective to the extent by
which the context of encoding corresponds to
the context of retrieval (Tulving & Thompson,
1973)
• Godden & Baddeley (1975)
– One group of Ss studied a list of words
underwater.
– Another group studied the words on land.
– At test, each group was further divided into and
recalled the words either underwater or on land.
Caption: (a) Design for Godden and Baddeley’s (1975) “diving”
experiment. (b) Results for each test condition are indicated by the
bar directly under that condition. Asterisks indicate situations in which
study and test conditions matched.
Caption: (a) Design for Grant et al.’s (1998) “studying” experiment. (b)
Results of the experiment. Asterisks indicate situations in which study
and test conditions matched.
Grant et al. (1998)
• Other methods to improve your memory (2:50)
• http://www.youtube.com/watch?v=BBjr4jKYEpw
&feature=related
• Things that impede your memory (1:35)
• http://www.youtube.com/watch?v=OHl7BewJ0y
U&feature=PlayList&p=8DE5E0C927437E3B&pl
aynext=1&playnext_from=PL&index=32
• (Q3) How is it possible that a lifetime of
experiences and accumulated knowledge
can be stored in neurons?
How are memories stored in the
brain
• Hebb (1948)
• http://en.wikipedia.org/wiki/Donald_O._Hebb
• Learning and memory are represented by
physiological changes at the synapse.
• Long-term potentiation (LTP)
Neuron IV
Neurons
Dendrites
Cell body
Axon
Synapse
Synapse and neurotransmitter
Dendrite
Axon
neurotransmitters
reach a terminal
of a dendrite of
the other neuron,
and change the
neuron’s resting
potential.
Synapse
Fig. 6-20, p. 209
• Neuroanimator demonstration
– Ch 13. 3: Long-lasting LTP
Forming Memories in the brain:
The fragility of new memories
• Memory loss
• Teenage memory loss due to concussion
(2:11)
– http://www.youtube.com/watch?v=gv4SJN016
hQ
• H. M.
– his hippocampus is surgically removed.
– He cannot form new memories
– He also lost memories of events up to 10-15
years before the operation.
H. M. had both anterograde and retrograde amnesia
Fig. 6-21, p. 209
Consolidation
• These examples show that memory for
recent events is more fragile.
• Some process of transferring of memory
occurs.
•  Consolidation
– Transforms new memories to a stronger less
fragile state.
Consolidation
Retrieval of episodic
memory initially depends
on the hippocampus.
Later, the hippocampus is
not involved in retrieval.
How does it happen?
-- >reactivation
Incoming
information
activates
cortical areas
and the
hippocampus
The hippocampus
replays the neural
activities
associated with a
memory. This
results in the
formation of
connections
between cortical
areas.
Eventually, the
cortical
connections
become strong
enough, and the
hippocampus is no
longer necessary.
Fig. 6-22, p. 211
What creates consolidation?
• Sleeping helps strengthen memory.
• A lot of neural connections between
hippocampus and neocortex.
• Neurons in hippocampus send neural
signals to neurons in neocortex while you
sleep.
• Synapse and learning (10:45)
• Teenagers and sleep deprivation
– http://www.youtube.com/watch?v=pqpOZd2LtI
o&feature=PlayList&p=8DE5E0C927437E3B
&index=24&playnext=2&playnext_from=PL
• Poor sleep and Alzheimer’s disease
– http://www.youtube.com/watch?v=WOC5a9h5
_dk
Additional materials
Memory for emotion
• A strong connection between emotion and
memory.
• We tend to remember well emotionally
charged experiences (both negative and
positive).
• Why?
LaBar & Phelps (1998)
Dolcos et al. (2005)
Arousing words (profanity,
sexually explicit words) are
remembered better than
neutral words
Emotional pictures are
also remembered better
than neutral pictures.
Fig. 6-26, p. 214
Why
The amygdala is the
center for processing
emotion.
The hippocampus is right
next to the amygdala.
• What happens if you don’t have
amygdala?
• DVD: Secrets of the mind
– (Capgras delusion; from 29:00 to 39:00 ) 10
min.
• A case study (imposter feeling) of a patient with
the damage to amygdala.
• http://www.youtube.com/watch?v=dqBGzkz1oDU