Long Term Memory

Question 1

MEMORY TAXONOMY

Answer 1

• simplified from human memory theory
  WORKING MEMORY VS LTM
• short term storage VS long term storage
  EPISODIC VS SEMANTIC/REFERENCE
• first day of Uni VS knowing Rescorla-Wagner is an associative learning model

Question 2

FORGETTING

Answer 2

• target memories could be lost due to:
  PROACTIVE INTERFERENCE
• from info acquired PRE target
  RETROACTIVE INTERFERENCE
• from info acquired POST target
  DECAY
• passage of time

Question 3

LONG-TERM MEMORY

Answer 3

• focus on retention over hour intervals/days/longer > minutes
• big issues = what transformations in memory trace take place between original encoding/final storage/if forgotten memories are lost completely/just become inaccessible
• forgetting should be considered as failure to retrieve; memory still there but animal is unable to access it under present conditions

Question 4

CONSOLIDATION

Answer 4

• initial memory trace = fragile/relatively short-term; needs to be transformed/consolidated into more durable trace for long term
• many studies looking at this used avoidance learning in shuttle box; rat is typically trained to move from one side to another to avoid shock
• lends itself to idea of forgotten memories being irretrievably lost

Question 5

SHUTTLE BOX APARATUS

Answer 5

• rat has to move from one side to the other to avoid shock
• if it stays on one side too long (30/60s) it gets shocked
• must hop low hurdle in middle of box to get between the halves

Question 6

PHYSIOLOGICAL DISRUPTION OF CONSOLIDATION

Answer 6

• several types of physiological trauma prevent learning ONLY if occur shortly post stimulus/reward
  DUNCAN (1949)
• electroconvulsive shock (ECS); sudden heating/cooling/drugs/concussive impact (ie. American football)
• so post learning shuttle response to avoid shock -> ECS given shortly post training disrupts performance post delay
• ECS given post delay/just before test = less effective

Question 7

DUNCAN (1949): AVOIDANCE

Answer 7

• animal put back in shuttle box post complete rest; observed if shuttling as before
• higher scores = better at avoiding shock
• ECS given just post training (20s) -> poor memory
• training/ECS time interval lengthens -> less effect
• 1-14 hours = same as controls (no ECS)
• ECS disrupts memory transfer of learned response (shuttling) to LTM (consolidation) -> no ECS effect
• implication = consolidation of memory disrupted by ECS given shortly post learning -> gone permanently as never enters LTM storage

Question 8

RETRIEVAL

Answer 8

• animal must retrieve memory to use it
• studies indicate that most forgetting should be viewed as failure to retrieve > storage loss
• most impressive = reactivation experiments; apparently lost memories = successfully retrieved following reminder treatment
• poses difficulties for consolidation theory; if memory not consolidated, how can it be retrieved?

Question 9

RETRIEVAL: GORDON & MOWRER (1981)

Answer 9

• animals trained to avoid shock; left for 3 days so forgetting = expected; final test given under 3 conditions:
  0 = tested; mean latency to shuttle = long via forgetting
  15 = held for 15s on one box side to remind previous training; animals shuttle almost immediately upon release; no further training indicates memory effect
  75 = held for 75s; shuttle slower; holding reminded of training BUT continuing to extinguishes fear
• reactivation by being exposed to training context can restore lost memories post ECS aka. paradox; evidence for both arguments

Question 10

ANIMAL LTM CAPACITY

Answer 10

VAUGHAN & GREENE
- picture recognition experiment w/pigeons
- random pseudo-concept task = slides of trees arbitrarily divided into positive/negative original training w/40 positives/40 negatives
- new slides introduced once old ones mastered
- successful training up to 640 slides
- birds trained w/320 slides rested for 2 years
- re-testing = forgetting BUT quick recovery

Question 11

EPISODIC MEMORY (?)

Answer 11

• less clear whether we can claim episodic memory in animals
  ROBERTS (2022)
• claims animals are “stuck in time”; cannot perform mental time travel
• BUT some claim otherwise…

Question 12

EPISODIC MEMORY: CLAYTON & DICKINSON

Answer 12

• claimed that food-storing birds (ie. scrub jays) show true episodic memory
• trained scrub jays to cache food in special sand-trays w/unique lego landmarks
• labs show they remember:
  1. what they stored (waxworms/peanuts); recover worms > peanuts as pref
  2. where they stored them
  3. when they stored them (recover peanuts > worms if stored 4+ hours before as worms perish)