Thanks for the memories
Functional aspects of memory
Richard Fielding
Department of Community Medicine
HKU
Outline
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Learning objectives
Memory concepts
Levels of processing
Storage: maintaining information
Retrieval
Forgetting
Memory breakdown
Improving memory
Conclusions
Learning objectives
• Outline the main performance
characteristics of sensory or peripheral
registers
• Outline the main components and features
of working (short-term) memory (STM)
• Outline the main features of long term
memory (LTM) and describe at least three
components of LTM
• Define encoding and stimulus organization
influences on LTM
• Give common reasons for “forgetting”.
Memory concepts
• Functionally, memory has three stages:
ENCODING
STORAGE
RETRIEVAL
• “Early” versus “late” selection of input.
• Available attentional capacity is
determining criteria for input selection
stage.
• Levels of processing: sensory, shallow,
intermediate, deep.
Levels of processing
• Sensory encoding - most superficial:
sensory stores “buffer” registers;
200ms. Eidetic; echoic registers.
• Attentional theory of remembering.
– Structural encoding
– Phonemic encoding
– Semantic encoding
Storage: maintaining information
• Information-processing models of memory
input
Sensory store
attention
rehearsal
Short-term (Working) memory
storage
retrieval
Long-term memory
Schematic of working memory
Storage in LTM
• Rehearsal of data in STM facilitates transfer
to LTM - (maintenance versus elaborative)
• Primacy and recency effects (first and last
information preferentially stored)
• Organization: if data not organized in LTM,
impossible to find anything: clustering,
concept hierarchies, semantic networks,
schemas/scripts.
Retrieval
• Recall a function of memory strength:
– weak, strong, weak consistent pattern of recall.
• Use of retrieval cues:
– tip-of-the-tongue phenomena = retrieval failure
– cues, such as first letter, aid recall of words.
– Event contexts: (crime scene reconstructions)
– mood: “state-dependent memory” vs. mood
congruence
– “reconstructive” memory
Forgetting
• Forgetting is rapid for meaningless data
~35% retention after 1 day.
• Why?
– Ineffective encoding
– Trace decay
– Interference (retroactive / pro-active)
– Retrieval failure.
Memory breakdown
• Amnesia - memory loss.
– Retrograde amnesia: loss of memories for events
prior to injury
– Anterograde amnesia: loss of memories for events
following injury.
• Do not confuse loss of content storage/ recall
with loss of ability to follow procedure.
• Implicit memory (retention when remembering
not intended), mostly unaffected by amnesia.
Suggests different memory systems involved.
• Declarative (fact) vs. Procedural (skill) memory
Improving memory
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Adequate rehearsal
Distributed practice
Minimize interference
Use deep processing
Emphasize transfer-appropriate processing
Enrich encoding with verbal mnemonics
Enrich encoding with visual imagery
Organize information
Conclusions
• Memory processes extensive and complex
• Numerous systems for memory and “types”
of memory
• Memory is not perfect recall, it is partially
reconstructive
• Relevance to medical practice in obtaining
history from patients and giving information
to patients.