Lecture 13 and 14 - Memory and Forgetting

Question 1

Recap: What is implicit and explicit memory

Answer 1

BOTH ARE TYPES OF LONG TERM MEMORY
Implicit Memory (Non-Declarative)
- Procedural (skills and actions)
- Emotional Conditioning

Explicit Memory (Declarative)
- Episodic (experienced events)
- Semantic (knowledge and concepts)

Question 2

Recap: What is a Single and Double Dissociation

What two patients make up the double dissociation example for this lecture series?

Answer 2

Single Dissociation
- Damage to brain AREA 1 results in disruption of FUNCTION A
- But a RELATED FUNCTION B is INTACT
indicates that functions A and B are at least partially different - but it could be that function A is harder so it got more affected by the damage

Double Dissociation
- Need to find patients who the exact opposite pattern: damage to AREA 2 which leaves FUNCTION A intact but disrupts FUNCTION B
indicates that functions A and B are independent from each other, rules out the generic difficulty account

Question 3

Who was patient HM?
Who was patient KF?

Answer 3

Double Dissociation of working and long-term memory in brain damage –> Patients HM and KF

Patient HM
–>amnesic syndrome (working memory intact) - eg. had normal recency effect in free recall
–> poor recall of earlier items (long-term memory impairment)

Patient KF
–> Poor immediate repetition of short word sequences (impairment of working memory)
–> able to learn such sequences if presented slowly (long-term memory intact)

Question 4

Implicit (Procedural) vs Explicit (Declarative) memory: What is anterograde amnesia?

Answer 4

Patients with ANTEROGRADE AMNESIA (such as HM) have drastically impaired ability to form new memories for experienced events and facts - eg. can’t form new declarative memories
BUT
Can exhibit normal learning rates in acquisition of..
- perceptual skills
- problem solving skills
- practical skills

Question 5

How can brain damage cause deficits in procedural (implicit) memory without impairing declarative (explicit) memory?

Answer 5

Impaired procedural (implicit) memory without impairing declared memory (explicit)
- Apraxia: problems with movement coordination
- Aphrasia: problems with speech
- Acalculia: problems with simple mathematical tasks
- Prosopagnosia: difficulty recognising faces

Question 6

Explicit/Declarative: What is Episodic memory? What is Semantic Memory?

Answer 6

Episodic: memory for individual autobiographical experiences - true ‘remembrance of things past’ (re-experiencing)

Semantic: general and conceptual knowledge abstracted from experience eg. what famous people look like, geographical and scientific knowledge

Question 7

Outline the Double Dissociation example for Episodic v Semantic Memory (Amnesic v Semantic Dementia)

Answer 7

Amnesia
- Amnesic patients tend to have anterograde amnesia (cannot form new memories) for both personal episode and knew knowledge, but…

There are AMNESIC PATIENTS (eg. KC, or Clive Wearing) who cannot..
- recollect ANY personally experienced events from birth (dense retrograde amnesia)
BUT
- pre-trauma knowledge of maths, history, geography, general knowledge is WELL PRESERVED

Patients with SEMANTIC DEMENTIA show…
- Progressive loss of knowledge of the world (word meanings, objects, places, people)
- Well-preserved autobiographical memory across lifespan and recent events

Question 8

Is episodic memory preserved in semantic dementia?

Answer 8

YES

Days 1/2:Tests of semantic memory
(a) object and sound knowledge
(b) pick where iconic European statues are on a map

Day 2: What/where/when questions…
“Was i wearing a clip?” “When was the map test”
memory for recent episodes

FOUND:
In controls and semantic dementia patients:
- Episodic memory was high (explicit - experienced events)
In semantic dementia patients
- Semantic memory (explicit - knowledge and concepts) was MUCH LOWER than controls

Question 9

How do we measure forgetting?

Answer 9

Learning —————————> memory test
retention interval

Recall Tests:
- Recall of events (hard to score)
- Free recall of lists of nameable items (%recalled)
- Cued recall (paired associations) - % recalled when shown half the pair, asked to recall the other
- Serial Recall (given list of words - %recalled in correct position)

Recognition Test
- Ability to discriminate “old” from “new” items (% correct)

typically found: as time goes on…people remember less and less

Question 10

Historically: How were experiments on LTM conducted (Ebbinghaus 1885)

Answer 10

He studied HIMSELF - learning many lists of 13 nonsense words and then relearned after a variable interval
–> He measured how long it took him to learn the whole list and repeat without error

FOUND:
–> Forgetting is ORDERLY - can often be described by a simple mathematical function of the retention interval

Question 11

What causes forgetting?

Answer 11

Encoding —————– Storage ——————-> Retrieval
(decay?)

Orderliness of forgetting might suggest some inevitable decay process: loss from storage

BUT: information not recalled now may be recalled LATER
–> AND - further prompts/cues may success in eliciting recall
so some cases of forgetting is due to retrieval failure NOT loss from storage

Bahrick: Longer retention doesn’t NECESSARILY increase forgetting
- No forgetting of school classmates over 30 years for STUDENTS
- But teachers showed much quicker levels of forgetting
Interferences: new students - memory traces get overwritten with new SIMILAR traces

Question 12

Paired Associate Learning: When is forgetting clearly attributable to interference?

Answer 12

“Paired Associate” learning: 1940s-1950s: participant must learn (say) 10 arbitrary pairing between “stimulus” and “response” words
–> P leans List 1, then List 2
–> Tested on either List 1 or List 2
FOUND:
- Later recall of List 1 –> WORSE when List 2 was learned afterwards - retroactive interference
- Later recall of List 2 –> WORSE when List 1 has been learned before - proactive interference

Question 13

Baddeley & Hitch (1977) outline their findings in ‘Time versus intervening (similar) experiences as predictors of event forgetting’

Answer 13

At end of season, 2 rugby teams recalled games played: clear forgetting over a season (though some games are more memorable)
–> Each player missed some games

If you control for time: the number of games played during the interval is a significant predictor of forgetting
more games played = increased forgetting / decreased recall

Retrieval failure is INCREASED by INTERFERENCE from SIMILAR MATERIAL

Question 14

Which factors influence memory retrieval (4)

Answer 14

1. Processing at encoding/acquisition
2. Consolidation after encoding
3. Interference from other memory traces at retrieval
4. Similarity of encoding and retrieval contexts

Question 15

Encoding: How does ‘organisation at acquisition’ effect memory
–> Include the research by Mandler (1967)

Answer 15

Deliberate ROLE REHEARSAL DOES increase later recall
- Hence the PRIMACY effect in free recall: first few items get more rehearsals
- Memory experiments show that actively organising material is an effective learning strategy

Mandler (1967)
–> Groups 1 and 2 sorted words on cards into categories of their own devising
- G1 was told to remember words, G2 was not
NO DIFFERENCE: in a later recall test
–> Group 3 did not categorise, just listed
- REMEMBERED LESS than Groups 1 and 2

Organising the material is what produces effective acquisition, not effort to learn (by itself)

Question 16

Encoding: How does ‘Depth of processing at acquisition’ affect memory?
–> Include the research by Craik and Tulving (1975)

Answer 16

Craik and Tulving (1975) showed a series of unrelated words, and gave groups one of three orientating tasks:
- Is it written in upper/lower case
- Does it rhyme with X?
- Does it fit into a sentence (eg. The man broke his __)

LATER did an unexpected recognition test

FOUND: Highest recognition when processed in a sentence

Question 17

Encoding: What are two popular methods to demonstrate the power of elaboration at acquisition

Answer 17

Mnemonics
–> First, learn the rhyme
–> To learn a sequence: form a vivid image representing the rhyme item for position X in interaction with what you want to remember at position X
–> To remember: just go through the rhyme
*Binds ideas to a pre-established framework which organises them

Method of Loci (eg. for learning a speech)
–> First, memorise a route around a familiar building or garden, so that you can walk around it in your ‘mind’s eye’
–> Learning the speech: At each point in the route, form a striking image representing the idea you want to mention at that point
–> Remembering: Traverse the route, reading and interpreting the images
*Encourages formation of rich nexus of associations between the fame and the concept

*General Moral: effectiveness of learning involves forming associations among representations that ALREADY EXIST IN THE MIND - including representations of…
o Elements of the new experience/fact
o Elements of the context
o Elements of prior knowledge

Question 18

Consolidation: Outline PHASE 1

Answer 18

HIPPOCAMPAL/MEDIAL TEMPORAL TRACE

After a traumatic brain injury (eg. concussion) or ECT - there is often RETROGRADE MEMORY LOSS spanning many minutes, even HOURS (way beyond duration of ‘working memory’)
–> disruption of process of consolidation of memory trace in hippocampal/medial temporal cortex system

Consolidation of novel traces suffers INTERFERENCE from consolidation of further novel traces (remembering lots of stuff at the same time)

sleep improves memory for material learned recently
alcohol and barbiturates impair learning - disrupt consolidation –>BUT improve memory for material learned just before

Question 19

Consolidation: Outline PHASE 2

Answer 19

ROBUST TRACE ELSEWHERE IN THE CORTEX

Over a longer timescale (months/years) recent LTM traces are more vulnerable to hippocampal damage than older traces
–> Amnesic patients with damage to hippocampus/medial temporal cortex show gradient of retrograde amnesia over the years - older memories BETTER PRESERVED (Ribot’s Law - eg. HM)

If you reactivate memory traces - makes them more robust - they are now stored ELSEWHERE in the cortex (no longer dependent on the hippocampus)

Question 20

Retrieval: What is competitive associative interference?

Answer 20

Interference in retrieval is MAXIMAL when the same (or similar) stimulus items are used for each list: competition between two associative links from the same retrieval cue
–> RETRIEVAL CUES COMPETE

Question 21

Example of Associative Interference: What is the ‘Fan Effect’

Answer 21

More facts needed to learn –> harder to retrieve a particular fact…

Participant learns 0-4 new “facts” about each of set of famous people
eg. Napoleon had a wart on his nose
–> Later true/false reaction time measured for
ACTUALLY TRUE STATEMENTS
EXPERIMENTAL TRUE STATEMENTS
FALSE STATEMENTS
FOUND: longer reaction times for retrieval when more fantasy facts learned

Question 22

How can the effects of associative interference be mitigated?

Answer 22

THEMATICALLY RELATING THE FACTS
–> It has been claimed that if the facts are thematically related, the fan effect is ELIMINATED
–> The thematic relationship enables the learner to form associations between the separate facts using pre-existing knowledge schemas, which provide multiple retrieval paths

Question 23

How is reconstruction vulnerable to associative intrusions?

Answer 23

We interpret what we see and hear via learned “schemas” or “scripts” - knowledge of typical patterns or event sequences
–> When we try to remember - we recover only FRAGMENTARY ASSOCIATIONS (from which we reconstruct the event)

We fill in the gaps using:
–> General knowledge schemas (in semantic memory)
–> Fragments remembered from other episodic sources

Question 24

What are false memories and how do they occur?

Answer 24

It is easy to create false memories: “recognition” “recall” and “recollection” of events that did not happen because…
- SOURCE AMNESIA: retrieval of info coupled with inability to remember its source
- RECALL IS RECONSTRUCTIVE: fragments of actual experience get combined with other information in memory whose source is lost

Question 25

Loftus and Palmer: Outline their false memories research (2 types)

Answer 25

1. Car Crash Experiment
   o 100 ppts see film of car crash and answer a series of questions…including: About how fast were the cars going when they smashed into/hit each other
   o One week later asked “did you see any broken glass”
   –> SMASHED: 16/50 said yes
   –> HIT: 7/50 said yes
   *misinformation implied by interrogation after the event is incorporated into the subject’s reconstruction of the event
2. Lost in the Mall experiment
   –> Loftus and her colleagues planted a false memory in participants’ minds that they had been lost in a shopping mall as a child. The participants were given narratives about four events from their childhood, three of which were true and one false—the experience of being lost. Afterward, many participants reported remembering the false event, indicating the susceptibility of memory to suggestion
   –> 25% of subjects remembered being ‘lost’

Question 26

False Memories about emotional events that never happened:

Answer 26

• being abducted by space aliens
• committing embarassing acts at public events
• suffering injuries requiring hospitalisation

1992 El Al crash in Amsterdam: 10 months later - “Did you see the television film of the moment the plane hit the building?”
–> 50> % said yes

Question 27

What is the Context-Content Paradox

Answer 27

The way emotions affect false memories depends on….
–> whether the emotion is part of the to-be-remembered event (eg. airplane crash)
–> or whether (negative) mood is the context in which something is remembered

NEGATIVELY perceived events are MORE PRONE to disruption - they heighten susceptibility to suggestion and misinformation
BUT
NEGATIVE MOOD during the to-be-remembered event seems to protect against it

Question 28

How do context effects aid encoding/retrieval?

Answer 28

As a general rule…information is more easily retrieved if tested in the same context in which it was acquired
–> Environmental Context (Godden & Baddeley, 1975)
o Divers learned word lists on dry land or underwater
o In between all subjects moved between environments
o Best retrieval when learning and retrieval context is the same

Question 29

What is State-Dependent Learning?

Answer 29

Sensitivity of retrieval to congruence with the INTERNAL context at the time of learning
–> Eich (1975) - retrieval highest in similar conditions of normal/weed smoked
–> Similar effects of induced sad/euphoric moods

Encoding-specificity is causal in the maintenance of depression; negative memories are more accessible in the depressed state, and their retrieval reinforced the depression

Question 30

How does motivation to learn influence what we learn?

Answer 30

Learning is EASIER when in this state of motivation and curiosity –> driven by a desire to know and the rewarding feeling of learning something interesting
–> eg. Lawnchair Larry story (attaching balloons to lawnchair)
EVEN THOUGH: no effort invested into studying