Re-consolidation and Retrieval Induced Forgetting (Week 4)

Question 1

Re-consolidation

Answer 1

Standard consolidation model- assumed once memories were consolidated they were stable and could resist changed.
However, recent research- suggests reactivating a memory places it back in a plastic state capable of being changed.
- so must be stabilised again = re-consolidation.

Question 2

Old theory (Misanin, Miller & Lewis, 68)

Answer 2

Susceptibility to amnesia for an event is due to the state of the memory trace for the event.
Experimental criteria:
- reactivate consolidated memory.
- administer treatment to alter reconsolidation.
- test for retention after window for reconsolidation has closed.

Window for reconsolidation is the time period that memory is fragile again.

Question 3

Misanin, Miller & Lewis (1968)

Answer 3

Fear conditioned rats given ECT:

• immediately after fear conditioning (prior to synaptic consolidation) OR…
• 24 hours after fear conditioning and after presentation of conditioned stimulus (consolidation complete and memory reactivation) OR…
• 24 hours after fear conditioning without presentation of stimulus (consolidation complete, no memory reactivation) OR…
• two control groups given ECT after memory reactivation or without.

Question 4

Results of rat study

Answer 4

ECT immediately after and ECT + reactivation had very high lick rates (suggest rats are happy).
- No longer feared the stimulus.
The other three conditions were fairly low- no ECT + reactivation being the lowest.

Question 5

Timeline of reconsolidation in animala

Answer 5

Approx begins 2-10 mins after memory reactivation (Monfils et al, 09).
Most takes place within 2 hours.
Complete by 6 hours (Duvarci & Nader, 04).

Question 6

In humans

Answer 6

Finding evidence is complicated.

• methodology used on animals is too invasive for human research- protein synthesis inhibitors are used to inhibit memory is unethical to use on humans.
• early failure to replicate with humans (Squire, Slater & Chace, 76) found ECT influenced recent memories more than remote ones but not effect of a reminder of previous learning.

Question 7

Walker, Brakefield, Hobson & Stickgold (2003)- procedural memory

Answer 7

Day 1: learn finger tapping sequence.
Day 2: learn second sequence (interference).
Group A- learned second after reactivating memory for day 1 sequence.
B- learned second without reactivating memory of day 1.
Day 3: tested for memory of day 1.
Group A made more errors on day 1 sequence.

Showed day one sequence once reactivated became plastic and allowed it to be harmed by interfering information.

Question 8

Hupbach, Gomez etc (2007)- episodic

Answer 8

List of objects.

Interference affected the list if reactivated and put into plastic state.

Question 9

Disrupting declarative memory with reconsolidation

Answer 9

Chan & LaPaglia (2013) found reinstating a memory (fictional terrorist attack) led to more vulnerability to misinformation.

Question 10

Limitations

Answer 10

Suzuki et al, 04:
- weaker memories are easier to change via reconsolidation.
- stronger reactivation of learned experience, the more changeable the memory becomes.
Sevenster et al, 2012:
- reactivation wasn’t enough for reconsolidation of a fear memory- new info also needed to be present.
Requirement of new info is consistent with hypothesised role of reconsolidation (needs to be relevant)- memory updating.

Question 11

Is it really re-consolidation?

Answer 11

Taubenfeld et al (2001) with animals- found in dorsal hippocampus, protein synthesis is crucial for consolidation but not reconsolidation.
- concluded the two processes are different- require either different molecular mechanisms or different brain areas.

Question 12

Implications

Answer 12

Enhancing memories- can we make learning more efficient?
- Rodriquez et al (2013).
Lots of research into this- eg. smaller spaced out study sessions is more efficient than one large study session.
Disrupting memories- can we help those suffering from maladaptive memories (PTSD).
- Kroes et al (2014) etc- looking at possibilities to help those with PTSD.
- mixed thoughts about this.
Might explain false memory effects: eg. memory conformity with other eye witnesses.

Question 13

Retrieval induced forgetting (Anderson et al, 94)

Answer 13

Examined through ‘retrieval-practice paradigm’.
Stage 1: ppts study category pairs (eg. fruit- banana).
Stage 2: ppts undertake retrieval practice (eg. fruit - (prompt) or…)- some word completion pairing.
- or baseline condition with no retrieval practice.
Stage 3: ppts undertake recall of all examples they can remember seeing from category.

Findings: words they had practice on they remembered better.
- boost the things practiced and hurt the things you didn’t.

Retrieval is required for the effect (ie. retrieval specificity).
During retrieval practice stage you need to actively recall the cued item, rather than passively view that pairing.

Question 14

Macrae & MacLeod (1999)- real world example

Answer 14

Standard retrieval paradigm with two fictitious islands.
Recall for retrieved facts = 70%.
Recall for non-retrieved factors (control) = 38%.
Recall for non-retrieved related facts = 23% (RIF effect).

Question 15

Social retrieval induced forgetting- how you discuss an event may shape your memory

Answer 15

Conroy & Salmon (2006):

• Children undertook some activities and discussed for several with the experimenters.
• final day had to recall the events.
• memory less good for the non-discussed items compared to the no discussion condition (ie. retrieval induced forgetting).

Question 16

Social retrieval induced forgetting- Cuc et al (2007)

Answer 16

Effect even found when you watch someone undertake the ‘retrieval practice’.
2 ppts sat adjacently learning same items.
P1 undertakes RP while P2 watches.
Both undertake subsequent recall of list items.P1 exhibits RIF but so does P2.

Question 17

RIF mechanisms: associative blocking

Answer 17

Cue word (eg. fruit) becomes more strongly associated with competitor word (orange- following retrieval practice). 
The cue word then repeatedly cues the competitor word (orange) because the association is strong and every time it is recalled it strengthens that association- self perpetuating effect. 
Consequently, it's harder to recall the target (non studied related word, eg. banana) due to interference of the competitor. 

This is premised on strength dependent competition- because association is stronger, that is why orange is repeatedly recalled.
Storm et al, 2006- examined whether RIF is still found when retrieval practice pair has impossible answer (eg. fruit- lu…)- nothing gets strengthened yet RIF is still found.
- RIF is strength independent.

RIF is also interference dependent.
- occurs more for high frequency example (eg. banana) than less frequent (eg. lychee).

Question 18

RIF mechanisms: associative unlearning

Answer 18

The association between the cue and the target is weakened every time it is incorrectly recalled- association is punished.
When generating fruit during retrieval practice, accidentally recalling ‘banana’ will be punished because it is incorrect- result in unlearning the association between fruit and banana.

Real life- in terms of cognitive efficiency.
- eg. punishing the memory every time you recall an old password.

Question 19

RIF mechanisms: inhibition

Answer 19

Sometimes it is maladaptive for strong memory to be recalled.
We then inhibit or suppress that memory.

Inhibition vs. Associative unlearning:

• if inhibited- responding in general to banana should be reduced (effect should generalise to novel cues).
• if association unlearnt- forgetting should be confined to the pairings used during retrieval practice (cue dependence).

Question 20

Inhibition and RIF: attention

Answer 20

Inhibition of memory leading to RIF appears attention dependent.
Reduced retrieval induced forgetting when: participants undertake a secondary task (Anderson et al, 94)- concurrently listening to digits and responding when three consecutive odd digits.
- people with ADD.

Neuroimaging data support: Kuhl et al (2007):

• as retrieval ractice progressed there was less activity in anterior cingulate cortex and both the dorsal and ventrolateral prefrontal cortex.
• consistent with initial inhibition of highly accessible (but incorrect) items during retrieval practice.
• level of deactivation in the PFC correlated with degree of RIF for non-practiced but related items.

Question 21

Summary

Answer 21

Retrieving memories can lead to the forgetting of non-recalled but related items- requires retrieval specificity.
Because:
- associative blocking- probably not because effect is strength independent and interference dependent.
- associative unlearning- probably not because effect is cue independent.
- inhibition- requires attention.