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