Chapter 6 - Memory

THEMES:

• What is Memory

• Encoding

• Storage

• Retrieval

• Forms of Long-Term Memory

• Memory Failures

Intro to Memory

PROCESSES OF MEMORY

1. Encoding → Translating information into a neural code so that it can be stored for later use

2. Storage → The process by which information is retained over time

3. Retrieval → Pulling information back out of your mind for use

THREE COMPONENT MODEL

1. Sensory memory

2. Short-term/working-memory

3. Long-term memory

Sensory input → Sensory Registers → (encoding) → W/STM → (encoding) (retrieval) ← LTM

Sensory Memory

• Sensory Memory → Briefly hold sensory info.

• Sensory Registers → Part if S.M., initial information processor

  • Iconic store → Holds visual information

  • Echoic store → Holds auditory information

Short-Term Memory

• Short-term memory → Temporarily stores and processes a limited amount of information in consciousness

• Information storage:

  • Visually

  • Phonologically

  • Semantically

  • Actions

  • Errors can happen if you try to store too much information in one system too quickly

• Increasing capacity:

  • Chunking (Amount) → Grouping units into larger bits

  • Control Processes (Duration)

    • Maintenance rehearsal (simple repetition)

    • Elaborative rehearsal (focus on meaning)

• Working memory → Limited-capacity system for storage and manipulation of information for complex tasks

  • Holds on to info in active memory to work on (eg. mental math)

• The difference between short-term and working memory is short-term memory is made-up of a single component and is concerned with storing information, working memory is made-up of multiple components and is concerned with manipulation information.

Long-Term Memory

• Long-term memory → Library of memories, durable storage of past events and learned knowledge. It’s unlimited, a large storage capacity. It lasts a lifetime

  • Not affected by Dementia, Dementia is a failure of retrieval

• Long-term memory

  • Declarative memory

    • Semantic memory

    • Episodic memory

  • Procedural memory

• Declarative memory (explicit memory)

  • Can be verbalized

  • Consists of episodic (personal experiences, episodes) and semantic (general factual knowledge) memory

• Procedural memory (implicit memory)

  • Cannot be verbalized

  • Skills and actions (even some conditioned responses)

• Damage (amnesia)

  • Anterograde amnesia → Loss of abilities to assimilate and retain new knowledge

  • Retrograde amnesia → Loss of memory for past events

CASE STUDIES

• HM case study

  • Action → bilateral temporal lobectomy to lessen epilepsy

  • Effect → Caused anterograde amnesia

  • Meaning →

    • Working memory does not require medical temporal structures

    • Declarative memory and procedural memory are different

    • Medial temporal structures are important for semantic and episodic memory

• KF case study

  • Action → motorcycle accident

  • Effect → short-term memory damaged, LT intact

  • Meaning → LT does not require a functioning short-term memory to encode new information

• Clive Wearing case study

  • Action → virus attacked his CNS (hippocampus)

  • Effect → Anterograde and retrograde amnesia but was still able to learn new tasks

  • Meaning → Using implicit/procedural (unconscious) long-term memory and repeated exposure allows performance of tasks without need of conscious control or attention

LISTS

• Serial Position Effect → describes the relationship between a word’s position in a list and its probability of recall

  • Primacy Effect → It’s easy to remember things at the beginning of the list

  • Recency Effect → It’s east to remember things you’ve encountered most recently (end of list)

  • ‘U’ pattern

Encoding

• Effortful processing

  • Effortful, intentional conscious process

  • eg. Studying for a class

  • Ways of ensuring that encoding works well:

    • Maintenance Rehearsal → repetition, not the best way to improve recall

    • Elaborative Rehearsal → Adding to the info. (meaning, concepts, memory)

• Automatic processing

  • Unintentional processing, requires minimal attention

  • eg. You remember what you did yesterday without consciously encoding it

• Levels of processing

  • Structural (Shallow) → Eg. capitals, font, italics

  • Phonetic (Deeper) → Eg. Rhyming

  • Semantic (Deepest) → Eg. Does it fit in a sentence: • Does the word fit in this sentence: “He saw the _____”?

  • Deeper processing facilitates stronger memory (recall)

• Organizing Information → Arranging information in a meaningful way enhances memory

  • schemes serve as a cue to aide retrieval of information eg. mnemonic devices

• Mnemonic Devices → Mental strategies that aide in remembering information

  • Simple →

    • Chunking → Combine items into lager units of meaning (phone numbers, words, etc.)

    • Hierarchy technique → Organize items based on how they are related (house, neighbourhood, city), it enhances memory due to associations (meaning makes info easier to recall)

  • Semantic → First-letter technique (ROYGBIV), Narrative technique (story)

  • Visual-based → Bizarre imagery, interactive imagery

  • Complex → method of Loci (linking what you need to remember with a place that you know well, real or not)

Storage

• Storage → How we retain information over time (eg. hard drive), but how do we know how it works?

  • We know that storage has to happen, we have a couple ideas of how it works

• Associative Networks → Theory that memory can be represented as a network of associated concepts

  • Each concept is represented by a node

  • Lines between concepts represent associations, length matters

  • Activating one concept will activate other related conceps

• Priming

  • The activation of a concept by another

  • Exposure to one stimulus influences a response to a subsequent stimulus

• Neural Networks

  • Also describe linked nodes, but nodes are physical (neurons), and do not contain a single unit of information

  • But….where is a single concept stored? → within that neural network, pattern or set of nodes that activate together (parallel distributed processing model)

Retrieval

• Process of transferring information from LTM back into working memory (consciousness)

  • Most of our failures of memory are failures to retrieve

• Value of distinctiveness

  • Things that stand out are more easily recalled eg. chickadee, hawk, duck, tomato, goose, chicken, owl

• Flashbulb memories

  • Memory for the circumstances in which you first learned about a very surprising and emotionally arousing events (many believe they can accurately recall all minor details about what they were doing at the time of this event)

  • Not a special type of memory that uses diff. system

  • Grows less accurate over time

  • Shows that enhanced emotional reaction to some event does NOT guarantee better retrieval of that information

• Cued Recall

  • Cues: Stimuli that lead to activation of information stored in LTM

  • Multiple cues lead to better retrieval and involves deeper processing

  • Self-generated cues work better

  • Priming tasks (magic tricks) (exposure to one stimulus influences a response to a subsequent stimulus)

• Matching conditions → Retrieval can be increased by matching the conditions at retrieval to the conditions that existed at encoding

  • Encoding Specificity → information is learnt together with its context

  • State-Dependent Learning → Learning is associated with a particular internal state

  • Transfer-Appropriate Processing → Memory performance is better if the type of task at encoding matches type of task at retrieval

Forgetting

Why do we forget??

• Encoding failure

  • Lack of attention or deep processing

  • Brain only encodes what it deems important

• Decay of Memory Trace

  • Long-term physical trace in nervous system fades away over time with disuse (don’t use it, you lose it)

• Interference Theory

  • Information forgotten because other items in LTM impair ability to retrieve it

  • Proactive Interference → Past material interferes with ability to recall older information

  • Retroactive Interference → New information interferes with ability to recall older information

• Motivated forgetting

  • Repression → may protect us by blocking the recall fo anxiety-arousing memories

  • Based on Freudian concepts

  • Conscious or unconscious process??

• Amnesia

  • Retrograde

  • Anterograde

• Dementia

  • Refers to impaired memory and other cognitive deficits that accompany brain generation and interfere with normal functioning

• Alzheimer’s Disease

  • Severe retrograde and anterograde amnesia

  • Spreads across the temporal lobes and to the frontla lobes and other cortical regions

• Memory Distortion

  • Memory is a constructive or reconstructive process → how we visualize the world

  • Piece together bits of information in ways that intuitively “make sense”

  • Often highly inaccurate!!

  • Schemas can distort memories

  • Important for eye-witness testimony → Suggestive questioning can lead to inaccurate recall and witness may not even be aware