Memory 4 - Storage failures

Question 1

What is Psychoanalysis and hypnosis?

Answer 1

1. Psychoanalysis: during analysis patients may recover memories for traumatic or unpleasant events which seemed to have been lost
   - Issues: false memories, repression, does this only apply to some specific events
2. Hypnosis: under hypnosis people may be age regressed to recall lost details of their lives, or details from crime scenes
   - Issues: suggestibility, does hypnosis add anything to interviewing?

Question 2

Brain stimulation

Answer 2

• Wilder Penfield’s work in the 1940s on Epileptics
• Direct stimulation of the temporal lobes results in patients spontaneously reporting memory-like events
• BUT they examined 1132 patients (520 temporal lobe patients) and only got experiential reports from 40 of them – they only reported vague sounds
• Only 12 patients reported things that could be identified as being past experiences
• The events reported may be closer to dreams than to memories

Question 3

3 Mechanisms for forgetting

Answer 3

1. Encoding – failure to encode
2. Storage – decay, interference, repression
3. Retrieval – retrieval failure
   - Decay on info stored in memory

Question 4

Decay or interference?

Answer 4

• Keppel & Underwood (1962) demonstrate that Brown-Peterson forgetting is at least partly caused by Proactive Interference rather than decay
  a) Retroactive Interference: New learning causes forgetting of old material
  b) Proactive Interference: Old learning causes forgetting of new material
• The fact that Brown/Peterson forgetting is due to proactive interference is demonstrated clearly by the release from PI phenomenon - a change of category brings performance close to the levels of trial 1 again

Question 5

Interference from misinformation

Answer 5

Loftus & Palmer (1974):
- Participants watch a film of a car accident
- One group are asked “About how fast were the cars going when they smashed into each other”, a second group are asked “About how fast were the cars going when they hit each other”
- The first group give higher speed estimates than the second group
- One week later both groups are asked whether they saw any broken glass in the film of the accident (“smashed” 32% yes, “hit” 14% yes)
- Loftus (1979) interprets her results as showing that the original memory itself has been distorted by misleading post-event information
- This is extremely important for work on eyewitness testimony and on recovered memories because it implies that false components of memories can be added by an experimenter / interrogator / therapist
- Trace destruction? They argue that eyewitness testimony results such as those reported by Loftus, Miller & Burns (1978) demonstrate that the memory trace can be irrevocably altered by subsequent information

Question 6

Loftus, Miller & Burns (1978)

Answer 6

• 195 students watch a series of 30 slides depicting a car accident. Critical slide contains either a yield (give way) sign or a stop sign
• Participants then answer a 20 item questionnaire including the question:
• “Did another car pass the red Datsun while it was stopped at the stop sign?” Or “Did another car pass the red Datsun while it was stopped at the yield sign?”
• After 20 minute filler task participants are tested on a series of 15 slide pairs (including the critical one)
• Where question was consistent performance was 75% and misleading performance was 51%
• Effect is increased with delay (2 weeks vs. 20 mins), Reduced by forewarning or blatancy, but Unaffected by incentives ($25)
• But the misinformation effect never seems to work on all the participants in the misled group
• Could it just be a form of response bias for participants where no initial memory was encoded
• Thus, no destruction of the original memory trace required

Question 7

Permanence of memory: Nelson (1978)

Answer 7

• Standard Paired Associate Learning:
• 24 people, 20 pairs to learn each (480 items)
• Four Week Delay then Testing by Recall, Recognition & Relearning
• At (Cued) Recall 232 items are forgotten
• Of these 120 are not Recognized
• But when these 120 “forgotten” items are relearned it is easier to learn old associates rather than new ones:
• Performance: new 20%, old 50%
• Apparently forgotten memories can still influence behavior
• More recent work provides potential neural signatures for “forgotten” memories

Question 8

Does everyone forget? ‘s’

Answer 8

• S. appeared to have almost unlimited memory for numbers and equations
  a) Equation memorised after a few minutes
  b) Perfect Surprise Recall 15 years later
  c) Number grids of almost unlimited size memorised given about 3 to 4 seconds per item
• S. had no specific training - relied on imagery, synaesthesia and some strategies such as ‘Method of Loci’

Question 9

Problems with an infinite memory – ‘s’

Answer 9

• S. Had remarkably poor memory for faces
• “They’re so changeable - it’s the different shades of expression that confuse me and make it so hard to remember faces.”
• Lists provided by Vygotsky included bird names. S. could recall the lists but didn’t know that there were birds on the list until “reading off” list again
• Inability to forget eventually created problems for S
• “The Paradox of the Expert” – why doesn’t it become harder to learn new things as more items are already in memory? Surely capacity limits, or proactive interference would create problems for experts
• S. is extremely unusual in apparently demonstrating incredible memory for almost all types of material

Question 10

Storage (retention) failures?

Answer 10

• Human memory is certainly not always perfect but examples of complete loss from storage are hard to find
• Amnesia associated with Dementia, is one clear example, but not all amnesia does show permanent loss from memory e.g. Retrograde traumatic amnesia
• Even apparent failures of memory usually don’t provide clear evidence of complete trace destruction
• Expert Mnemonists demonstrate that astonishing amounts of material can be stored, virtually forever
• Normal forgetting may be more associated with a progressive loss of availability for individual memories due to interference