Thanks for the memoriesFunctional aspects of memory

Richard Fielding

Department of Community Medicine

HKU

Outline• 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• 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.