4. L4 principles of memory

Question 1

duel store model and evidence for duel store model of memory

Answer 1

• The duel store models are based on the idea that memory is organised into LTM and STM and these have separate sets of abilities and limitations

Evidence for duel stores
Serial position curves
- Order of presentation predicts the probability of free recall of each item
- Any given item on the list can be mapped as either recalled from STM or recalled from LTM
- At the beginning of the curve: LTM (Primacy effect)
- At the end of the curve: STM (recency effect)
- In the middle of the curve: easily forgotten

Question 2

Distinctiveness as a principle of memory
faces
lists

Answer 2

Distinctiveness is memory
- Unique or distinctive stimuli are easier to remember
- Overarching principle ^

Distinctive faces
- Distinctive faces are better remembered than typical faces
- Faces made more distinctive by caricaturing are better remembered

Distinctive lists
- Distinctive sequences recalled better
- Irregular pronunciation: denial, glove, comb
- Low word frequency found in English language more distinct
- Encode distinctively by pronouncing regularly
- Distinctively pronounced lists remembered extremely well (+25%)
How to make list distinctive
- Pronounce lists with different pronunciation
- E.g. denial become dee nee al

Question 3

temporal distinctiveness

Answer 3

Temporal distinctiveness
- Temporal distinctiveness is based on the idea that memories are—at least in part—organised in terms of their time of acquisition (psychological time)
- Memories that are encoded at the same time are more difficult to retrieve
- Therefore memories can be retrieved with reference to a time dimension (time as a retrieval cue)

Question 4

temporal distinctiveness
Physical time vs psychological time

Answer 4

Physical time
- Time is whole units evenly spaced
- distinctive time does not matter

Psychological time
- If remembered temporal position is used as a cue the success of that recall depends on temporal isolation
- As time passes things recede further into the past
- Logarithmic compression “scrunches” them up
- Temporal distinctiveness is defined as the extent to which an item is separated from its neighbours in psychological (i.e., compressed) time
- Less distinctive items are harder to retrieve
- Due to interference from neighbours (the closer, the more interference)
- Therefore items are only distinct for a brief amount of time
relative time is what matters for recall

Question 5

temporal distinctiveness explains the serial position curve (recency effects) even in delayed conditions

Answer 5

• Even if we increase the time between items we still see primacy effects, even if the items go further than 20 seconds (max STM storage in dual effect models) even in the delay condition. Essentially there is no effect of the delay
• This is due to scale invariance: the recency of an item relative to the distance between items therefore Memory could be the same:
  ○ if the last item is recent and they are all close together
  ○ if the last item is distant and they are all widely separated in time
• Amount of recency determined by the ratio of time between the inter-presentation interval (IPI) and retention interval (RI)

Question 6

Distinctiveness and primacy effects in the serial position curve

Answer 6

• The edge effect: is that items on the edge of a list (the beginning) have less items to be confused with and therefore more easily retrieved
  • The further away from the edge we move the more interference from neighbouring items
  • Therefore memory of items in the middle will be the worst
  • Time is a bad retrieval cue for early items
  • In this case something like and n emotional cue would be better
    So for patients who have access to LTM but not STM could be explained that they have lost access to that temporal dimension and instead can use emotional cues to remember things

Question 7

Implications of temporal distinctiveness:
Post study rest
Sleep on memory
pre-study rest

Answer 7

effects of post study rest
- Rest after study can lead to astonishing improvement in recall, especially in memory-impaired patients (Della Sala, Cowan et al., 2005)
- Increases temporal distinctiveness and prevents interference

Beneficial effects of sleep on memory
- Most likely a combination of temporal distinctiveness and neural ‘consolidation’ mechanism during slow-wave sleep (Born et al., 2006)
- Synaptic consolidation is a Presumed neural process (synaptic transmission enhancement and protein synthesis), stabilizing newly created memory traces during periods of mental inactivity. The reactivation of newly established patterns and connections

Rest before study can also improve memory:
- predicted only by TD theory (Ecker et al., 2015; McGhee et al., 2020)
- Maybe you can insulate something you’ve learnt by resting before and after

Question 8

Criticisms of TD

Answer 8

• Continuous input of information is not preserved as continuous
• People spontaneously parse ongoing events into episodes
• Memory is better for information from the current episode
• Crossing event boundaries impairs memory

Radvansky & Copeland (2006)
- “Walking through doorways causes forgetting”
- People picked up, carried, and put down various objects in a virtual environment
- Memory for objects currently carried or just put down was better while still in the same room
- Independent of time or temporal distinctiveness

Ezzyat & Davachi (2011)
- Reading of narrative text
- Boundary markers such as “After a while,…” leads to parsing into episodes
- Given a sentence, retrieval of the subsequent sentence is better within such episodes than across