Transcript 2320Lecture23x - U of L Class Index

Upcoming
March 23
March 25
Overview of Memory
Sensory Memory
Short-Term/Working Memory
(Brooks expt. 1)
March 30
April 1
Long-Term Memory
Long-Term Memory and False
Memories (Loftus)
April 6
April 8
Amnesia (Sacks)
Consciousness and
“Perception without
Awareness”
April 13
April 15
Subliminal Messages (Vokey
and Read)
Memes (Dawkins)
Recalling Episodic Memory
When You Don’t Remember
• Two reasons why you don’t remember:
When You Don’t Remember
• Two reasons why you don’t remember:
• Unavailable
– It wasn’t successfully encoded - something
went wrong while you were studying
When You Don’t Remember
• Two reasons why you don’t remember:
• Unavailable
– It wasn’t successfully encoded - something
went wrong while you were studying
• Inaccessible
– memory is stored but cannot be retrieved,
perhaps because appropriate connections
aren’t being made
Implicit and Explicit Memory:
yet another distinction
• Are all memories explicit? Is all
information stored in the brain subject to
conscious scrutiny?
Implicit and Explicit Memory:
yet another distinction
• Are all memories explicit? Is all
information stored in the brain subject to
conscious scrutiny?
• Implicit Memory refers to encoded
memories that are not part of the
“contents” of awareness
Implicit and Explicit Memory:
yet another distinction
• How can we know whether memory is
stored/recalled implicitly or explicitly?
Implicit Memory
• Consider the following distinction in recalling
items from a list of words:
Implicit Memory
• Consider the following distinction in recalling
items from a list of words:
• Free Recall - subjects can be asked to simply
recall and report as many items as possible these items are accessible as explicit memory
Implicit Memory
• Consider the following distinction in recalling
items from a list of words:
• Implicit Recall - subjects can be asked to
complete a word stem with any word that
comes to mind after reading a list of words
(no mention of testing memory!)
__ack
Implicit Memory
• Consider the following distinction in recalling
items from a list of words:
• Implicit Recall - subjects can be asked to
complete a word stem with any word that
comes to mind after reading a list of words
(no mention of testing memory!)
But how do you know that information is stored/recalled
implicitly? Couldn’t it be explicit?
Implicit Memory
• Consider the following distinction in recalling
items from a list of words:
• Twist - require subject to complete stem with
a word that wasn’t on the list - if a word from
the list is used preferentially, it was
remembered implicitly
Implicit Memory
Consider the implications regarding the
nature of consciousness and the
connection between neural activity and
awareness
Implicit Memory
Consider the implications regarding the
nature of consciousness and the
connection between neural activity and
awareness
Not all of the activity in your brain generates
experience - some is “sub”conscious or
non-conscious
Recalling Episodic Memory
• Recall is a generative processes rather
than simply calling up stored data
Recalling Episodic Memory
• Recall is a generative processes rather
than simply calling up stored data
• Evidenced by the fact that episodic
memories can be distorted or
completely false under certain
circumstances
Recalling Episodic Memory
• Misinformation Effect - exposure to
information subsequent to storage of
memory can alter the contents of the
memory
Recalling Episodic Memory
• Misinformation Effect
• Consider the following example:
– Subjects were shown a video depicting a
car accident
Recalling Episodic Memory
• Misinformation Effect
• Consider the following example:
– Subjects were shown a video depicting a car
accident
– Then given the following question: “How fast were
the vehicles going when they ______”
Recalling Episodic Memory
• Misinformation Effect
• Consider the following example:
– Subjects were shown a video depicting a car
accident
– Then given the following question: “How fast were
the vehicles going when they ______”
– Different subjects were asked questions that
differed in the “magnitude” of the final word
Recalling Episodic Memory
• Misinformation Effect
• Consider the following example:
– Subjects were shown a video depicting a car
accident
– Then given the following question: “How fast were
the vehicles going when they ______”
– Different subjects were asked questions that
differed in the “magnitude” of the final word
– The possible words were: Contacted, Hit,
Bumped, Collided, and Smashed
Recalling Episodic Memory
• Misinformation Effect
• Consider the following example:
– Average estimated velocity depended on
the nature of the question
Recalling Episodic Memory
• Misinformation Effect
• Interpretation:
– Episodic memory can be distorted by
subsequent information
Recalling Episodic Memory
• Memory for episodes in life can be
illusory
Recalling Episodic Memory
• Memory for episodes in life can be
illusory
• Consider the example in Loftus’ article:
– participant was induced to have an episodic
memory of being lost in a mall
Recalling Episodic Memory
• Memory for episodes in life can be
illusory
• Consider the example in Loftus’ article:
– participant was induced to have an episodic
memory of being lost in a mall
– Even when told the memory is a false one, the
participant had difficulty recognizing it as an
invalid memory
Recalling Episodic Memory
• False Memories may arise when details
of a crime are in question as in eyewitness testimony or repressed
memories of abuse during childhood
Repressed Memories
Elizabeth Loftus
“Derepressed memories”
• Loftus opens with several examples of
court cases that involve “derepressed
memories”
• What is a repressed memory?
• What is a derepressed memory?
Loftus’ position in this article
• Loftus does not reject the notion of
repressed memories
– 18% - 59% of abuse survivors report
having regained access to previously
repressed memories
Loftus’ position in this article
• Loftus does not reject the notion of
repressed memories
– 18% - 59% of abuse survivors report
having regained access to previously
repressed memories
• What does Loftus challenge?
Loftus’ position in this article
• Loftus does not reject the notion of
repressed memories
– 18% - 59% of abuse survivors report
having regained access to previously
repressed memories
• What does Loftus challenge?
…That all “de-repressed” memories are accurate memories.
High Stakes
• Survivor of real
abuse might struggle
for years or decades
with consequences
and need to confront
the repressed
memory in order to
recover emotionally
• False accusation could
tear family apart and
send an innocent
person to jail
What’s the issue?
• What does Loftus express concern about regarding
the derepression of memories?
What’s the issue?
• What does Loftus express concern about regarding
the derepression of memories?
– reality of the memory is in question if it is recalled under
certain circumstances
What’s the issue?
• What does Loftus express concern about regarding
the derepression of memories?
– reality of the memory is in question if it is recalled under
certain circumstances
• What is the course of events that Loftus finds
worrisome?
What’s the issue?
• What does Loftus express concern about regarding
the derepression of memories?
– reality of the memory is in question if it is recalled under
certain circumstances
• What is the course of events that Loftus finds
worrisome?
This memory might
be false!
Therapist or Popular
Book suggests that
patient consider
possibility of abuse
Patient engages in
intense effort to
recall
An explicit
episodic
memory is
achieved
Model of Memory
RETRIEVAL
ATTENTION
Sensory
Signals
Sensory
Memory
Short-Term
Memory
Each time memory is retrieved and re-encoded it is
susceptible to distortion – particularly by other
information available at the time of retrieval
Long-Term
Memory
REHEARSAL
What’s the issue?
• So we potentially have a situation in which someone
who is having troubles in life and is seeking answers
is told to consider whether or not memories for abuse
exist
• What are some techniques that are used to “assist”
recollection?
What’s the issue?
• So we potentially have a situation in which someone
who is having troubles in life and is seeking answers
is told to consider whether or not memories for abuse
exist
• What are some techniques that are used to “assist”
recollection?
– hypnosis, imagery, dream analysis, story telling
– Loftus presents evidence that such processes may lead to
invalid memories or overconfidence in the validity of
memories
Conclusion:
• We cannot know with certainty (without corroborating evidence)
whether a derepressed memory is true
• Therapists should engage in probing this possibility very
carefully
– avoiding suggestive questions
– remaining unconvinced without corroborating evidence
– being “gently confrontational” to encourage patient to
consider the possibility that the events didn’t happen