Transcript BHS 499-07 Memory and Amnesia

BHS 499-07
Memory and Amnesia
Autobiographical Memory
Autobiographical Memory
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When we meet people we introduce
ourselves by exchanging memories.
• Excerpts from our “life story”
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Autobiographical memory covers events,
situations and other knowledge that
spans a person’s entire life.
• Autobiographical memory is a narrative.
Episodic or Semantic?
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Autobiographical memories are much
more than just episodic memory.
• More constructive and integrative.
• Spanning multiple events.
• Includes semantic-like generic info:
where
you work, phone numbers, etc.
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Semantic memories are affected by
autobiographical memory.
• We know more about personal heroes.
Levels of Autobiographical
Memory
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Event level – detailed, referring to
specific, individual events.
General level – referring to extended
sequences or repeated series of events
sharing a common component.
Lifetime period – broad, theme-based
portions of a person’s life.
• Relationship theme, work theme.
Event-Specific Memories
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These most closely correspond to
episodic memories.
• Involve a common activity at a particular place
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Lots of perceptual and contextual detail.
Includes internal context material about
emotional reaction and physiological
state.
May be lost or may endure over time.
Four Characteristics of Enduring
Event-Specific Memories
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Memories of originating events – a
childhood experience that sets someone
on a goal-related path to a career.
Turning points where a life is suddenly
redirected.
Anchoring events for a belief system.
Analogous events used to guide future
behavior – e.g., embarrassing moments.
General Event Memories
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Two types:
• A sequence of event-specific memories that
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form a larger episode (such as the first day of
a new job).
A repeating event (such as a class taken).
There is often a personal goal that is
affected by the extended event.
Integrative and interpretive thinking used
to link events into a single memory trace.
Lifetime Period Memories
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Long periods organized along some
common theme.
• Early childhood, career, education.
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Recall of autobiographical memories
beyond a general event is organized
along a theme.
Evidence for the Hierarchy
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This is a heuristic because there are
many examples of memories that don’t
fit – it is unclear where they belong.
• Smaller parts can be nested into larger ones.
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People have different aspects of their
lives going on concurrently – overlap.
Neurological Evidence
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Amnesics can recall general event and
lifetime periods but not specific events.
• S.S. (herpes encephalitis) – can remember
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his job
K.C. (motorcycle accident) – general semantic
knowledge but not specifics, e.g., floorplan of
house he grew up in, but not his own room.
K.S. (rt. anterior lobectomy for epilepsy) –
recalled specifics but not general info.
Memory as Life Narrative
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We organize the events of our lives into
a narrative structure, not semantic.
• Our life is told as a story
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We access info using basic event
components: people, places, activities,
other themes.
• Anything stored with the event can be a cue,
e.g., odors.
Recall of Narrative Memory
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When people remember, they recall
clusters of memories around a theme.
• People remember items related causally to
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one another.
People remember items that share the same
person, place or activity – not time.
Semantic memory is used to make the
memories more narrative in style.
• Better at recalling forward, than backward.
Perspectives
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Field memories – experienced from the
original perspective, as lived.
• More emotional, common in PTSD
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Observer memories – experienced from
outside ourselves, perhaps even
watching ourselves, detached.
• We could not do this if memory were not
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constructed.
More likely to be older memories, self-aware.
Schema-Copy-Plus-Tag Model
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The older memories become the more
schema-consistent because schemas
are used to fill in missing info.
• We better remember the parts that are
unusual, so memory doesn’t feel stereotyped.
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Model says people remember schemas
plus tags with the deviations, making the
memory unique.
Item-Specific vs Relational
Processing
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This distinction between schemas and
tags is like the semantic distinction
between item-specific and relational
processing.
• Difficult to tell which schema-consistent
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events really happened and which didn’t.
It is easy to tell how the event was different
than the schema (tag contains that info), even
though it may not be the most important info.
Infantile Amnesia
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Our earliest memories come from
around age 2-4.
Many reported memories from earlier
ages actually come from seeing pictures
or hearing family stories.
A lot of learning occurs during the first
two years, but nearly all events are lost.
Explanations
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Psychodynamic view – repressed by the
developing superego because they
involve fantasies about sex with parent.
Neurological view – the hippocampus is
undeveloped at birth and only reaches
adult form after a few years.
Schema organization view – infants do
not yet have organized schemas.
More Explanations
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Language development view – language
is needed to form a coherent narrative.
• Preverbal children do not translate knowledge
into verbal info until they learn how to talk.
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Emergent self view – infants lack a
sense of themselves as separate from
environment, no “I” as causal agent.
• Autobio memories construct around sense of
self.
Multicomponent Development
Theory
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There are a number of memory abilities
or components that emerge to bring
about autobiographical memory.
• Adequate episodic memory system
• Knowledge of how adults think and talk about
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the world and the passage of time.
How a person understands himself or herself.
Different cultures have different offset
ages for infantile amnesia.
Reminiscence Bump
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Memories of a person’s life are
dominated by those from around age 20.
Free-listing of autobiographical
memories shows:
• Recency effect, standard forgetting curve into
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the past.
Bump between 15 and 25.
Explanations
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Cognitive view – occurs because the memories
around 20 are the first ones of their type, a
primacy effect.
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Life scripts may guide recall with positive life
transitions around the bump times.
Neurological view – people reach their peak at
the bump time, declines after.
Identity formation view – people decide who
they are at that time in life with better
connectivity.
Flashbulb Memories
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Vivid memories with great detail,
relatively resistent to forgetting:
• Challenger explosion, Princess Di’s death,
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9/11
Include memory for the context, not just event
“Now Print!” mechanism in neural coding
– original explanation but no support.
Normal memories, not special.
Accuracy of Flashbulb Memories
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Because they are like normal memories,
inaccuracies can creep in over time, they
can be forgotten.
Because they are emotionally charged,
people believe they are more accurate.
• The stronger the emotional reaction, the more
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the memory is believed.
Pearl Harbor example – no baseball in Dec.
How are they Formed?
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What we remember better is our reaction
to the event, not the event itself.
Distinguishing qualities:
• The event must be novel (surprising) – less
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likely to be affected by interference.
The event must have serious consequences
for the person experiencing it.
An intensive emotional reaction must occur.
What Strengthens Them?
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Emotionally intense events raise arousal
which aids memorization.
More attention, more elaborative
processing and more reminders lead to
better recall.
Events are rehashed repeatedly, so
more practice.
Knowledge is needed for elaboration.