Theories of Forgetting & Manipulation of Memory

Chapter 7Unit 3 Psychology ~ 2012

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Theories of Forgetting• Retrieval Failure Theory• Interference Theory

– Retroactive Interference– Proactive Interference

• Motivated Forgetting• Decay Theory

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Theories of Forgetting

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Retrieval Failure Theory• We forget because the right cue or prompt is

not used to retrieve the information stored in memory.

• Retrieval cues act prompts/hints that guide the search and recovery process within memory.

• RETRIEVAL CUE: any stimulus that assists the process of locating and recovering information stored in memory.

• Retrieval Failure Theory – We sometimes forget because we fail to use the right cues to retrieve information stored in memory

• Also known as Cue-Dependent forgetting

Tip of-the-tongue phenomenon

• Tip Of The Tongue phenomenon is the feeling of being aware that you know something, being confident you will remember it at any moment but not being able to retrieve the information at that point in time.

• Partial Retrieval Process – Bits of information can act as retrieval cues for the required information

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Interference Theory• Forgetting in LTM occurs because other

memories interfere with the retrieval of what we are trying to recall, particularly if the other memories are similar.

• The more similar the information, the more likely it is to interfere with retrieval.

• There are 2 kinds of interference:– Retroactive Interference– Proactive Interference

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Interference Theory (cont…)• RETROACTIVE INTERFERENCE:

– When new information interferes with the ability to remember old information

– New learning interferes with the retrieval of previously learned information.

• PROACTIVE INTERFERENCE:– When information learned previously

interferes with our ability to remember newly learnt information.

Old Information New InformationAttempting

toRetrieve

OLD Information

Old Information New InformationAttempting toRetrieve NEW

Information

Retroactive Interference

Proactive Interference

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Exam Question• Compare retrieval failure theory and

interference theory in terms of forgetting.

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Exam Answer• In retrieval failure theory, forgetting occurs

because you cannot access the appropriate cues, whereas interference theory argues that material cannot be recalled because memories for other material prevent access to the material that you are attempting to recall (retro-active interference) or memories may not be efficiently stored because of the presence of previously learned material (pro-active interference).

• Many students fell into the trap of merely rephrasing the question in their answer, without explaining the meaning of ‘retrieval failure’ or ‘interference’.

Motivated Forgetting• Forgetting that results from a strong motive or

desire to forget, usually because the experience is too disturbing or upsetting to remember.

• There are two types of motivated forgetting:1. REPRESSION– the unconscious process through which an

individual blocks a memory of an event or experience from entering conscious awareness.

– Repression is a form of self-defence from the anxiety or distress associated with the experience .

2. SUPRESSION – the deliberate, conscious effort to keep an event

or experience out of conscious awareness. 11

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Exam Question• According to Freud, we can repress

memories.a. What is repression? b. Explain the difference between

repression and suppression.c. Repression and suppression are

both forms of ____________ forgetting.

Exam Answer• A. The unconscious blocking of memory of an experience

from conscious awareness (because of the distressing or disturbing nature of the experience)

– Students were not awarded marks if they used the term ‘repressed’ in their response without explanation.

– Responses such as ‘repression is when memories are repressed unconsciously’ did not gain a mark.

• B. Repression refers to the unconscious blocking of memory of an experience, whereas suppression refers to a conscious process.

• C. Motivated

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Decay Theory• Based on the assumption that when something new is

learned a physical or chemical memory trace containing stored information is formed in the brain as the information is consolidated in LTN

• Forgetting occurs because a memory (or memory trace) fades through disuse as time passes, unless it is reactivated by being used occasionally.– MEMORY TRACE: a physical or chemical trace in the

brain that contains the stored information.• This theory provides a physiological explanation for

forgetting.• Research shows that there is a pattern of gradual

deactivation of neural pathways in the hippocampus (part of the brain where consolidation of memories occurs).

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Exam Question• According to decay theory, why

are some memories forgotten?

Exam Answer• Information is forgotten because of the

gradual loss of a physical (biological/bio-chemical, etc.) memory trace; it is a reversal/dissolution of the change made when the memory was formed (consolidated).– Many students simply indicated that the ‘... memory

faded because it is not revisited over time’, which was not a full explanation.

– Students needed to explain that it is this lack of revision that then enables the memory trace – a physiological change in the brain chemistry – to disappear.

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Manipulation of Memory

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Forgetting• Forgetting refers to the inability to retrieve

previously stored information.• There is a characteristic pattern in which

information is forgotten, as demonstrated by various experiments.

• The FORGETTING CURVE shows the pattern (rate & amount) of forgetting that occurs over time.

• Forgetting is rapid at first, then declines gradually as time passes.

• More than HALF the memory loss occurs within the first hour after learning.

• The more meaningful the information, the slower the rate of forgetting.

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Exam Question• Anna works in a supermarket and has been asked

to learn 20 sequences of numbers that represent the codes for 20 items. Each sequence appears to be meaningless. She learns the list in one session but does not view or use the sequences in the list again for three weeks.With reference to the features of the forgetting curve, how might Anna’s rate of forgetting the sequences be affected during the three weeks after learning them?

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Exam Answer• The greatest rate of forgetting would occur immediately

after learning. • After about eight hours, memory loss would slow to a

steady decline and after a few days, little or no more forgetting would occur.

• One mark was awarded for each of the above points. In general it is very important for quantified amounts to be reported accurately. In this case, however, the items are strings of numbers and mnemonics such as chunking will mean that we could not predict the values on the curve accurately – in this case, therefore, descriptive terms were acceptable. Students who used Ebbinghaus’ figures were given full credit.

Measures Of Retention• In what ways are we able to find out how WELL

information has been “retained” in memory? We look at the retrieval methods…

• RECALL the ability to remember information with few cues to aid retrieval. This is the LEAST sensitive measure of retention.– FREE RECALL

• The ability to remember as much information as possible in no particular order

– SERIAL RECALL• The ability to remember information in the same

order that it was presented– CUED RECALL

• Making use of specific cues to aid retrieval.

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Activity - Recall

• After being dived into three groups each individual must try to recall the words above– Group 1 Individually write down as many words that you

remember– Group 2 Individually Write down the list in order– Group 3 After receiving a slip of paper from your teacher

Individually write down as many words as you can– Once you have finished write down which type of recall

you were required to use

PenDrinkTreeSnow

PhotoFourSockBlack

DogManEyeNorth

CowBookPegGarden

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Measures Of Retention• RECOGNITION the ability to identify the

correct information to be remembered among given alternatives or a set of distracter items. This method provides more cues than the recall method, hence it is a more sensitive measure of retention.

• RELEARNING the MOST sensitive measure of retention as it requires the re-learning of information previously memorised and then measuring the amount of time or learning trials saved in this process via a “savings score”.

Measuring Relearning• Relearning involves earning information

again that has been previously learned and stored in long-term memory.

• If information is learned more quickly the second time, it is assumed that there must be some information retained from the first learning experience.

• Relearning is also called the “method of savings” as it can be used to measure the amount of information saved from previous learning.

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Relearning & Calculating A Savings Score

• The formula for calculating a savings score:

SAVINGS = No. of trials for original learning – No. of trials for relearning x 100

No. of trials for original learning 1

• Savings scores are expressed as a percentage (%).

• Scores can be calculated using – the number of trials required to learn/relearn

or – the time taken to learn/relearn information

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Relearning & Hermann Ebbinghaus

• Hermann Ebbinghaus (1885) was the first researcher to study relearning.

• Ebbinghaus used himself as the research participant.

• He memorised a list of non-sense syllables under various practice conditions.

• Ebbinghaus measured his memory for what he learned.

• He found that if he couldn’t remember any items from the original list, he could relearn them more quickly a second time than he had initially learnt the list.

• He concluded that some information must have been retained from the initial learning. 27

Relative Sensitivity Of Measures Of Retention

• SENSITIVITY as a measure of retention refers to the ability to assess the amount of information that has been stored in memory.

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Most Sensitive

Least Sensitive

RELEARNING

RECOGNITION

RECALL

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Improving Memory• To ensure that information goes beyond

sensory memory, attention must be given to it.

• It must also be organised and integrated into the information already stored in long-term memory.

• This can be achieved via several methods that help to enhance memory:– Context- & State- Dependent Cues

recreate the conditions under which the required information was originally learned.

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Context-dependent cuesEnhancing Memory

• Environmental cues in the specific context (setting) where a memory was formed.

• These environmental cues act as retrieval cues.

• These cues may include the sights, sounds and smells within that specific situation.

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State-dependent cuesEnhancing Memory

• Associated with an individual’s internal physiological and psychological state at the time the memory was formed.

• Memory recall is better when performed under the same state as when the memory was formed

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Mnemonic Devices• Acronyms – Pronounceable words formed from the

first letter of a sequence of words e.g. EFTPOS• Rhymes – A phrase or string of words with an

emphasis on similar sounding key words• Acrostics – The first letter for each item is used to

construct a sentence of phrase• Peg-word Method – Memorising a rhyme or jingle

that has mental ‘pegs’ on which you hang items to be remembered

• Narrative Chaining – Linking otherwise unrelated items to one another to form a meaningful sequence or story

• Method of Loci – Uses a well learned sequence of locations as a series of retrieval cues for information to be recalled

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Narrative ChainingEnhancing Memory

• Involves linking items to one another (chaining) to form a meaningful sequence or story (narrative).

• These items are normally unrelated.• This method is particularly useful when

trying to remember items in order.• The story that is formed adds organisation

and meaningfulness to information that would otherwise be meaningless.

• The story will only be helpful if it hangs together well.

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Method of LociEnhancing Memory

• This method uses a well-learned sequence of locations as a series of retrieval cues for the information to be recalled.

• The individual would associate the information with landmarks in a familiar place or parts of a building.

• This is another method that helps to remember information in a particular order.

• The ‘method of loci’ elaborates the information to be learned by linking it with memory cues that are very familiar.

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Method of Loci (cont…)• This method involves:

– first learn, in their naturally occurring order, some locations that are easily distinguishable and well known to you (eg: the route you take to school)

– Then associate a visual image of the items to be remembered with a location in the sequence.

– When you need to remember the information, you mentally revisit each place in the sequence, retrieving from each place the image associated with it.

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Manipulation of Memory• A Leading Question is a question that has content

or is phrased in such a way as to suggest what answer is desired

• Leading questions can be used to manipulate memory

• Presupposition – Information that should or must be true in order for the question to make sense

• ELIZABETH LOFTUS conducted research in the field of memory reconstruction

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Elizabeth Loftusexperiment 1

• Two lab experiments that looked at the influence of question wording on memory and how that information can distort a witness’s memory

• 45 volunteer students shown seven film clips of car accidents and were asked to write a description of what they had seen as well as being asked to answer questions on the estimation of the speed of the cars

• 5 Conditions of the experiment with 9 participants being randomly assigned to each condition

• Each condition contained a different word that was used to asked the question about ‘How fast were the cars going when they ______________ each other?’

• The blank words included; smashed, collided, bumped, hit and contacted

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experiment 1 (cont…)• Results indicated that the wording of the

question influence the speed estimations given by the participants with the most intense word ‘smashed’ brining the highest estimated speed.

• The results were found to be statistically significant

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Elizabeth Loftusexperiment 2

• 150 volunteer students who were randomly assigned to one of three groups (conditions) and viewed a one-minute film that included a four-second scene of a multiple car crash

• Group One was asked ‘how fast the car were going when they smashed into each other’

• Group Two was asked ‘ how fast were the cars going when they hit each other?’

• Group Three was not asked a question about the speed of the cars

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experiment 2 (cont…)• The results found that the group with the

intense word had a higher mean score (10.46mph) compared to the less intense word (8.00mph)

• The results were found to be statistically significant

VERB CONDITION  

Response ‘Smashed’ ‘Control’ ‘Hit’

Yes 16 7 6

No 34 43 44

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experiment 2 (cont…)• One week later participants returned for the

second part of the experiment where they were required to answer a series of 11 question with the critical question being hidden amongst the others ‘did you see any broken glass?’

• There was no broken glass• Results showed that more

participants who had been given the questions with the word ‘smashed’ reported seeing broken glass (16) over those that were give the word ‘hit’ (7)

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Findings of Loftus’ Experiments

• Overall it was found that participants formed a memory of the crash and then integrate the new ‘false’ piece of information supplied after the event

• The participants were unable to tell if the key information in their memory had come from different sources – Source Confusion.

• This arises when the true source of the memory is forgotten

• This lead Loftus to propose that any model of memory should include the process of reconstruction

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Eyewitness TestimonyAre you a good eyewitnesshttp://www.youtube.com/watch?v=iav4n6X9jGo

Dr Phil ‘Leading Questions”http://www.youtube.com/watch?v=XORIWLgEVwE

Quick Quiz

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• Question 1: What is forgetting?• Answer: • Question 2: According to retrieval failure theory, why do we

sometimes forget? • Answer: • Question 3: What is another name for retrieval failure theory? • Answer: • Question 4: What is a retrieval cue?• Answer: • Question 5: What is the tip-of-the-tongue phenomenon?• Answer: • Question 6: Experiencing the TOT phenomenon is usually

associated with feelings of happiness. True or false?• Answer: • Question 7: A limitation of retrieval failure theory is that there is

no research evidence to support it. True or false? • Answer:

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Quick Quiz ~ Answers• Question 1: What is forgetting?• Answer: The inability to retrieve previously stored information. • Question 2: According to retrieval failure theory, why do we

sometimes forget? • Answer: Because we lack or fail to use the right retrieval cues to

retrieve information stored in memory. • Question 3: What is another name for retrieval failure theory? • Answer: Cue-dependent forgetting. • Question 4: What is a retrieval cue?• Answer: Any stimulus that assists the process of locating and

recovering information stored in memory. • Question 5: What is the tip-of-the-tongue phenomenon?• Answer: A state or feeling that occurs when you are aware of

knowing something, but you are not able to retrieve it from memory at that point in time.

• Question 6: Experiencing the TOT phenomenon is usually associated with feelings of happiness. True or false?

• Answer: False, it is usually associated with feelings of frustration.• Question 7: A limitation of retrieval failure theory is that there is

no research evidence to support it. True or false? • Answer: False.