L7 - Forgetting

Question 1

What is forgetting?

Answer 1

A failure to recover information once encoded, a trace of which may or may not exist

Question 2

How is forgetting measured conceptually?

Answer 2

Relative forgetting - forgetting is measured over time, or across experimental manipulations

Question 3

How did Ebbinghaus analyse the rate of forgetting?

Answer 3

Tested participants on a list of nonsense syllables until they reached 100% accuracy. Then subsequently tested recall/retention at varying intervals, from 20 minutes to 30 days after learning.

Question 4

What does Ebbinghaus’ forgetting curve show?

Answer 4

That memory for the items decreases most rapidly after an hour, and that after that forgetting rates are much more gradual.

Question 5

What is the type of function of the forgetting curve?

Answer 5

Logarithmic

Question 6

How did Meeter, Murre and Janssen (2005) study the forgetting of personal memories?

Answer 6

Determined the forgetting rates for PPS’ memories of public events from headlines and TV broadcasts, using questionnaires on recall and recognition

Question 7

What did Meeter, Murre and Janssen (2005) find about the forgetting of personal memories?

Answer 7

Recall for events showed a steep initial drop, and was followed by a slower forgetting rate.

After several years, 31% of the information could be recalled by PPS and 52% could be recognised, demonstrating the greater memory for recognition than recall.

Question 8

How did Bahrick, Bahrick and Wittlinger (1975) study forgetting of personal memories?

Answer 8

Tested 400 high school graduates on their ability to recognise and name classmates after delays of up to 30 years.

Question 9

What did Bahrick, Bahrick and Wittlinger (1975) find about forgetting of personal memories?

Answer 9

Ability to recognise faces, names and pair names with faces was unimpaired.

Ability to recall a name given a picture was extensively impaired.

Therefore, recall, but not recognition, of well-learned personal memories, closely follows the typical forgetting curve.

Question 10

Define consolidation

Answer 10

The time-dependent process by which new memory traces are gradually cemented and interconnected in memory.

Question 11

What are the 2 main types of consolidation?

Answer 11

Synaptic consolidation

System consolidation

Question 12

What are the 3 features of synaptic consolidation?

Answer 12

• Structural changes in the synaptic connections between neurons
• relies on biological processes
• occurs in the timeframe of hours-days.

Question 13

What are the 3 features of system consolidation?

Answer 13

• The gradual shift of a memory’s reliance from the hippocampus to the cortex.
• accomplished by repeatedly ‘replaying’ a memory until its various components are interconnected.
• can take up to the order of years to complete in humans.

Question 14

What is trace decay?

Answer 14

The idea that memories can simply fade over time and thus be forgotten

Question 15

What do some theories of trace decay propose?

Answer 15

It is just the activation level of the memory which fades, making it inaccessible. The physical trace is unaffected over time.

Opposing theories argue it is the decaying of the physical memory trace over time which is lost.

Question 16

What is the main criticism of trace decay theories?

Answer 16

They simply state that memory traces decay over time, and do not detail HOW (McGeoch, 1932).

Question 17

What are two types of disruptive processes that occur during waking hours?

Answer 17

• Contextual fluctuations

- Interference

Question 18

What do contextual fluctuations refer to?

Answer 18

Forgetting due to mismatches between encoding and retrieval context.

Question 19

What is interference?

Answer 19

Forgetting that occurs when a cue that is used to access a target becomes associated with other memories.

Question 20

When does retrieval competition arise?

Answer 20

When a reminder (cue) reactivates more than just one memory (target)

Question 21

What are the factors which cause interference?

Answer 21

• Competition assumption

- Cue overload principle

Question 22

What is the competition assumption?

Answer 22

When a cue is linked to multiple items, those items compete with the target for awareness

Question 23

What is the cue overload principle?

Answer 23

As a cue becomes attached to too many things, its capacity to access any one trace becomes compromised

Question 24

What is one explanation for retroactive interference (new information making old information more difficult to retrieve)

Answer 24

Associative unlearning

Question 25

What is associative unlearning?

Answer 25

Forgetting due to weak associations - i.e. forgetting of the weaker item due to stronger associations with a new competitor

Question 26

What is one explanation for proactive interference (old information making new information more difficult to retrieve)

Answer 26

Associative blocking.

Question 27

What is associative blocking?

Answer 27

Forgetting due to strong competitors - i.e forgetting of the weaker competitor due to stronger associations of the cue with previous competitors

Question 28

What is retrieval-induced forgetting?

Answer 28

Decreased memory for items that have not been rehearsed or retrieved post-learning, when other items have been (for which memory is increased).

Question 29

What is a real life implication of retrieval-induced forgetting?

Answer 29

In a courtroom - if witnesses, victims, or suspects are continuously interrogated on a particular aspect of a crime scene or event, but are not asked to recall specific aspects, memory for those specific aspects will be later impaired.

Question 30

What does RIF stand for?

Answer 30

Retrieval-induced forgetting

Question 31

What did Cuc, Koppel & Hurst (2007) find about socially shared RIF?

Answer 31

If a pair of participants both learn word pairs, and one PPS performs retrieval practice while the other listens, both will have impaired memory for the items that were not covered during the retrieval practice.

Question 32

What are the possible mechanisms underlying RIF?

Answer 32

• Associative unlearning
• Associative blocking
• Inhibition

Question 33

How might associative unlearning explain RIF?

Answer 33

Perhaps the learning of the association between one word pair, or between a cue and a target, (insect-spider) causes the unlearning of the association between another word pair, or another cue and target (insect-bee)

Question 34

How might associative blocking explain RIF?

Answer 34

The practice on the items that you retrieved between learning and recall tests (insect-worm, insect-spider) means that associations are so strong that it blocks the associations for the other word pairs (e.g. insect-bee).

Question 35

How might inhibition explain RIF?

Answer 35

Retrieval of one memory involves suppression of all competing memories.

Inhibition affects the activation level of the target memory itself- perhaps some information is simply suppressed (tested by providing further retrieval cues).

Question 36

What are the 4 properties of retrieval-induced forgetting that support the idea of inhibitory mechanisms?

Answer 36

• Cue independence
• Retrieval specificity
• Strength independence
• Interference dependence

Question 37

What is cue independence?

Answer 37

Forgetting due to inhibition generalises to independent/novel test cues.

(I.e. if an item has been forgotten due to inhibition, novel test cues will not jog the memory?)

Question 38

What is retrieval specificity?

Answer 38

Forgetting occurs only after retrieval practice, and not after other ways to strengthen memory (e.g. re-study).

Question 39

What is strength independence?

Answer 39

Frogetting does not depend on the strengthening of practiced items - it’s retrieval that matters

Question 40

What is interference dependence?

Answer 40

Interference by competitors during retrieval is necessary for RIF to occur.

Question 41

What was the assumption made in Penolazzi et al’s (2014) study into tDCS and RIF?

Answer 41

Cathodal stimulation over dPFC, during a RIF experiment, should disrupt inhibitory mechanisms behind RIF

Question 42

What did Penolazzi et al., (2014) find about tDCS and retrieval practice/RIF?

Answer 42

Cathodal stimulation during the retrieval practice stage led to unimpaired memory performance.

Question 43

What is a neural footprint?

Answer 43

A unique pattern of brain activity

Question 44

What did Wimber et al., (2014) find about RIF and neural footprints?

Answer 44

Increased activity for target memories, and simultaneous decreasing of activity for competing memories.

–> mechanism that is actively suppressing unpracticed items.

Question 45

What did Charles, Mather and Carstenson (2003) find about increased age and memory for unpleasant items?

Answer 45

Ability to remember unpleasant things becomes more impaired in older age groups.

Question 46

What is the motor evidence supporting intentional forgetting?

Answer 46

We seem to be able to inhibit reflexive actions. If we can do this in a motor context, why can’t there be an equivalent process for a memory context?

Question 47

What are the results on go/no-go tasks?

Answer 47

Improved memory performance on ‘go’ items and impaired performance on ‘no-go’ items.

Question 48

What do results on go/no-go tasks suggest?

Answer 48

Suggests we have a mechanism that can prevent us from retrieving previously studied items. Due to inhibition, because the ability to remember word pairs is not restored when further cues are provided.

Question 49

Which brain regions are thought to be active during go/no-go tasks?

Answer 49

Increased DLPFC activity, which is thought to be inhibiting the hippocampus in retrieving the memory.