Memory Flashcards
Define memory
Process in which we retain and recall information about events that have happened in the past
(Process = internal and mental)
Define Short-term memory (STM)
Memory for immediate events, which disappear if not rehearsed.
Sometimes referred to as working memory.
Define Long-term memory (LTM)
Memory for events that have happened in the past (between 2 minutes to 100 years ago → theorised to be unlimited).
It’s the permanent memory score.
Define sensory register
Stores a huge amount of information from our senses for a small range of time (one millisecond up to one second)
Define capacity
Amount of information that can be stored
Define duration
Length of time information can be held in the memory store
Define coding
Format in which information is stored in the memory stores → acoustic or semantic.
The process of converting information from one format to another.
Define acoustic coding
Information stored in the form of sounds.
Stored in STM.
Define semantic coding
Information stored in the form of the meaning of the experience.
Stored in LTM.
Define sensory register
Storage system that receives information from the sense organs.
It is not under cognitive control, but is an automatic response to the reception of sensory information.
If information is paid attention to, it passes on to the next store → STM.
If not paid attention to, the information fades away quickly through trace decay, leaving no lasting impression.
The separate sensory stores for different sensory inputs:
Iconic → Visual
Echoic → Auditory
Haptic → Touch
Gustatory → Taste
Olfactory → Smell
Match the sensory store to the sensory input,
Iconic:
Visual (sight)
Match the sensory store to the sensory input,
Echoic:
Auditory (sound)
Match the sensory store to the sensory input,
Haptic:
Touch
Match the sensory store to the sensory input,
Gustatory:
Taste
Tip: Remember gustatory with link to oesophagus
Match the sensory store to the sensory input,
Olfactory:
Smell
Coding in the sensory register
Information is stored in a raw, unprocessed form
Research: Coding in the sensory register
Crowder provides research evidence for different types of coding in the sensory register.
Crowder found that the sensory register retains:
→ Iconic information for a few milliseconds
→ Echoic information for 2-3 seconds
This suggests that there are different stores within sensory memory (therefore is not unitary) so different types of coding exist too.
Research: Capacity in the sensory register
The capacity of each sensory memory (visual, iconic etc) must be very large (potentially unlimited) given that the information contained within them is unprocessed, highly detailed and ever-changing formats.
Sperling provides research evidence that the capacity of each memory store within the sensory register is quite large.
Sperling studied iconic store of sensory memory by:
Flashed 3x4 grid of letters onto a screen for 1/20 th of a second.
Participants asked to recall the letters of one random row from the screen and to indicate which row had to be recalled (1st, 2nd or 3rd), Sperling followed it immediately with a tone (high, medium or low).
→ Recall of letters in indicated row was high (= 76% average)
This suggests that all of the information was originally there, indicating that the capacity of the sensory register, especially for the iconic store, is quite large and therefore potentially unlimited.
Research evaluation: Capacity in the sensory register
Method can be criticised because it *blacks Mundane realism** and ecological given that … is not an everyday task and is quite articifical therefore cannot be generalised to everyday life activities which is not valid and reliable ??
Research: Duration in the sensory register
All sensory memory stores have a limited duration, though the actual duration of each is not constant - different types of information decaying at different rates.
Different sensory stores appear to have different capacities and there is some evidence that duration decreases with age.
Sperling provides research evidence that the duration of each memory store within the sensory register is limited.
Sperling varied the conditions of his original 3x4 grid experiment by delaying the time between showing the letters and giving the tone. If there was a delay between the presentation of the grid and the sounding of the tone, more information was lost each time.
→ Only 50% available after 0.3 second delay
→ 33% available after 1 second delay
This suggests that the duration of the sensory register is only about 1 second (max)
Research: Coding in the STM
Baddeley explored the effects between acoustic VS semantic coding
Participants asked immediately after the presentation, to recall a list of 5 words in serial order (= the original order that it was read out in) from words in the 4 categories:
→ Acoustically similar words = words that sound the same (e.g. man, mad ,map)
→ Acoustically dissimilar words = words that sound different (e.g. pen, day, few)
→ Semantically similar words = words that have the same meaning (e.g. great, big, large)
→ Semantically dissimilar words = words that have different meaning (e.g. hot, old, late)
Findings:
→ Words with similar sounds (acoustically similar) were much harder to recall using STM than words with dissimilar sounds (acoustically dissimilar)
→ Similarity of meaning (semantically similar) had only a very slight detrimental effect on STM
Therefore STM relies on acoustic coding
Research: Coding in the LTM
Baddeley explored the effects between acoustic VS semantic coding
Participants asked 20 minutes after the presentation, to recall a list of 10 words in serial order (= the original order that it was read out in) from words in the 4 categories:
→ Acoustically similar
→ Acoustically dissimilar
→ Semantically similar
→ Semantically dissimilar
Findings:
→ When participants were recalling from LTM, recall was much worse for semantically sounds words than for semantically dissimilar words
→ Recall from LTM was the same for acoustically similar and acoustically dissimilar words
Therefore LTM primarily makes use of semantic coding
Research conclusions: Coding in memory
→ STM relies heavily on acoustic coding
→ LTM primarily makes use of semantic coding
What are acoustically similar words ?
Words that sound the same
(e.g. man, mad ,map)
What are acoustically dissimilar words ?
Words that sound different
(e.g. pen, day, few)
What are semantically similar words ?
Words that have the same meaning
(e.g. great, big, large)
What are semantically dissimilar words ?
Words that have different meaning
(e.g. hot, old, late)
What category are the words man, mad ,map ?
Acoustically similar
What category are the words pen, day, few ?
Acoustically dissimilar
What category are the words great, big, large ?
Semantically similar
What category are the words hot, old, late ?
Semantically dissimilar
What other word can coding be referred to as ?
Encoding (→ used in exam questions)
Evaluation of coding in STM and LTM
1) Some experiments have shown that visual codes are also used in STM
→ Brandimonte et. al found that participants used visual coding in STM if they were given a visual task (picture) and prevented from doing any verbal rehearsal in the retention interval (they had to say ‘la, la, la’) before performing a visual recall task. Normally we ‘translate’ visual images into verbal codes in STM but, as verbal rehearsal was prevented, participants used visual codes
→ Other research (Wickens et. al) has shown that STM sometimes uses a semantic code
This suggests that STM is not exclusively acoustic
2) In general LTM appears to be semantic but not always
→ Frost showed that LTM recall was related to visual as well as semantic categories
→ Nelson & Rothbart found evidence of acoustic coding in LTM
Therefore, it seems that coding in LTM is not simply semantic but can vary according to circumstances
3) Baddeley’s methodology has been criticised
→ In Baddeley’s study STM was tested by asking participants to recall a words list immediately after hearing it
→ LTM was tested by waiting 20 minutes
→ It’s questionable as to whether this is really testing LTM
This casts doubt over the validity of Baddeley’s research because he may not have been testing LTM after all
2 mark questions regarding: Capacity, duration, coding
‘Explain what is meant by capacity/ duration/ coding’
1) State the definition for the 1st mark
2) Give an example for the 2nd mark
E.g. Explain what is meant by coding (2 marks)
The format that the information is stored in the memory stored. For example, acoustic.
Research: Capacity in the STM
Jacob’s measured STM capacity using digit span
→ Average span for digits = 9.3 items
→ Average span for letters = 7.3 items
Jacob suggests it is easier to recall digits because there are only 9 of them, whereas there are 26 letters
To measure digit span, the researcher gives
e.g. 4 digits
The participant is asked to recall the digits in the correct order.
If the participant is correct, the researcher increases the digit by 1 more each time.
When the participant fails to recall no more than 50% of the digit string they are judged to have reached their capacity.
Miller published ‘The magic number plus seven or minus two’ (7±2) which is the capacity of STM.
This means that the capacity of STM is a range of 5 to 9 pieces of information.
Miller found that if people can recall 5 words as well as they can recall 5 letters, we chunk things together and can then remember them - process = chunking.
Research: Capacity in the LTM
Wagenaar created a diary of 2,400 events over 6 years and tested himself on recall of events NOT dates
→ Had excellent recall of the events
Therefore it can be concluded that LTM capacity is extremely large, potentially unlimited
Evaluation of capacity research in STM experiment
1) The capacity of STM may be even more limited as Miller’s findings have not been replicated
→ Cowan reviewed a variety of studies on the capacity of STM and concluded that STM is likely to be limited to about 4 chunks
→ Vogel’s et al. research on the capacity of STM for visual information (rather than verbal stimuli) also found that 4 items was about the limit
→ This means that the lower end of Miller’s range is more appropriate (i.e. 7-2=5)
This suggests that STM may not be as extensive as was first thought
2) It seems that the size of the chunk affects how many chunks you can remember
→ Simon found that people had a shorter memory span for larger chunks, such as 8 word phrases, than smaller chunks, such as one-syllable words
This continues to support the view that STM has a limited capacity but further refines our understanding - the size of the chunk matters
3) There are individual differences in terms of the capacity of STM - it is not the same for everyone.
Jacobs also found that recall (digit span) increased steadily with age
→ 8 year olds could remember an average of 6.6 digits
→ 19 year olds could remember a mean of 8.6 digits
This increase with age might be due to changes known brain capacity and/or development of strategies such as chunking.
This suggests that the capacity of STM is not fixed and individual differences may play a role
Evaluation of capacity research in LTM experiment
Anokhin supports the conclusions of this study.
→ He estimated the number of possible neuronal connections in the human brain is followed by 10.5 million km of noughts. He concluded that ‘no human yet exists which can use all the potential of their brain’.
This suggests that the capacity of LTM is limitless.
Why were participants instructed to speak aloud in the Peterson & Peterson experiment ?
To prevent mental rehearsal in the retention interval in order to achieve valid results which increases the accuracy of measuring the duration
Research: Duration in the STM
Aim to provide empirical evidence for the multi-store model.
Lab experiment conducted where 24 undergraduate students took part in 8 trials (8 tests).
On each trial participants were given a consonant trigram (= meaningless three-consonant syllables, e.g. TGH) and a 3-digit number to remember.
Students instructed to count backwards aloud in 3s until told to stop (e.g. number given = 943, count 943, 940, 937 …)
On each trial, they were told to stop after a different amount of time - 3, 6, 9, 12, 15 or 18 seconds (= a retention interval).
Asked to stop counting backwards and recall the trigram.
Percentage of trigrams correctly recalled was recorded for each retention interval.
The longer the interval delay, the less trigrams were recalled
→ Participants able to recall 90% of trigrams after a 3 second delay
→ Participants able to recall 20% of trigrams after a 9 second delay
→ Participants able to recall 2% of trigrams after a 2 second delay
STM has a limited duration of 18-30 seconds when verbal rehearsal is prevented.
The results of the study also show the STM memory is different from LTM in terms of duration.
Evaluation of duration research in STM experiment
1) A criticism of this research is that investigating STM in this way is rather artificial.
→ Trying to memorise consonant trigrams does not reflect most everyday memory activities where what we are trying to remember is meaningful. However, we do sometimes try to remember fairly meaningless things such as groups of numbers (phone number) or letters (postcodes).
Thus, although the task could be criticised for lacking mundane realism and ecological validity, it could also be argued that it does have some relevance to everyday life.
2) A criticism of the Petersons’ study is that it did not actually measure what it set out to measure, therefore lacks internal validity.
→ When the participants were counting down the numbers in their STM this may have displaced or ‘overwritten’ the trigrams to be remembered.
Thus, the forgetting in the Petersons’ study may have been due to displacement rather than decay, reducing the internal validity of the study and therefore the support that this study can offer for the duration of STM memory.
Research: Duration in the LTM
Also referred to as the ‘yearbook study’
Participants were an opportunity sample of 392 American ex-high school students aged 17-74 years.
Types of recall:
(1) Free call test
= Participants recalled the names of as many of their former classmates as possible
(2) Photo recognition test
= Participants asked to identity former classmates in a set of 50 where some were from their yearbook and some weren’t
→ Participants tested within 15 years of graduation = 90% accurate in photo recognition
→ Participants tested after 48 years of graduation = 70% accurate in photo recognition
→ Participants tested within 15 years of graduation = 60% accurate in free recall
→ Participants tested after 48 years of graduation = 30% accurate in free recall
*Therefore performance in free recall was worse than photo recognition**
Therefore LTM has a seemingly unlimited duration
Evaluation of duration research in LTM experiment
1) A strength of this research is that, unlike a lot of memory research, it studied real life memories.
→ When studies on LTM have used meaningless pictures, recall rates were lower.
Thus, this study’s findings have higher mundane realism and ecological validity and might be more useful in terms of explaining the duration of LTM memory than other studies.
2) The downside of such real-life research is that confounding variables are not controlled.
→ The researchers assumed that the last contact with their classmates would have been when they left school. Little consideration seems to have been made of participants seeing classmates in the intervening years or even of them having looked through yearbooks themselves.
Thus, confounding variables could have influenced the results, reducing the support that the study can offer for the duration of LTM.
Explain and evaluate the use of diary studies
= A type of case study
→ Only measures data for one person
therefore can’t be generalised to others meaning it lacks population validity given that his memory may be drastically above or below average
→ Bias
due to the fact that he investigated himself therefore is more subjective (less objective) and research is more prone demand characteristics
Capacity of STM
7±2 pieces of information
(range of 5 to 9)
Capacity of LTM
Unlimited
Duration of STM
18-30 seconds
Duration of LTM
Unlimited
Coding of STM
Acoustic coding
Coding of LTM
Semantic coding
Define displacement
Information gets pushed out by something new in our STM
Define (trace) decay
Memory of information fades overtime
Also referred to as ‘trace decay’.
Why does displacement occur ?
STM has a capacity of 7±2 pieces of information therefore if it has exceeded the maximum of 9 pieces of information, new information will push out the previous information as a result of the STM’s limited capacity
What is a consonant trigram ?
A meaningless three-consonant syllables
E.g. TGH
Why is it important that the consonant trigrams are meaningless
To eliminate the ability of chunking as that doesn’t measure memory’s true duration
What is empirical evidence ?
Numerical data derived from direct experience or experiments rather than theories and principles
Why is empirical evidence good ?
It reinforces psychology’s claim to be a science given that science only uses empirical evidence in order for something to be proved rather than theories and principles
What is chunking ?
Ability to improve STM by grouping information into ‘chunks’ to reduce the amount of items to remember, given that the STM has a limited capacity of 7±2.
The ‘chunks’ are received from our LTM.
Capacity of chunking in STM
Limited to 4 chunks
Coding in sensory register
Information stored in raw, unprocessed form
Sensory stores:
(1) Iconic
(2) Echoic
(3) Haptic
(4) Gustatory
(5) Olfactory
E.g. Visual information is coded to be stored into the iconic store
Capacity of sensory register
Very large → unlimited
E.g. Very large for the iconic store
Duration in sensory register
Minimum = 1 millisecond
Maximum = 1 second
Findings of Peterson and Peterson
(STM duration)
The longer the interval delay, the less trigrams were recalled
→ Participants able to recall 90% of trigrams after a 3 second delay
→ Participants able to recall 20% of trigrams after a 9 second delay
→ Participants able to recall 2% of trigrams after a 2 second delay
Findings of Bahrick et al.
(LTM duration)
→ Participants tested within 15 years of graduation = 90% accurate in photo recognition
→ Participants tested after 48 years of graduation = 70% accurate in photo recognition
→ Participants tested within 15 years of graduation = 60% accurate in free recall
→ Participants tested after 48 years of graduation = 30% accurate in free recall
*Therefore performance in free recall was worse than photo recognition**
Therefore LTM has a seemingly unlimited duration
Findings of Baddeley
(STM coding)
→ Words with similar sounds (acoustically similar) were much harder to recall using STM than words with dissimilar sounds (acoustically dissimilar)
→ Similarity of meaning (semantically similar) had only a very slight detrimental effect on STM
Therefore STM relies on acoustic coding
Findings of Baddeley
(LTM coding)
→ When participants were recalling from LTM, recall was much worse for semantically sounds words than for semantically dissimilar words
→ Recall from LTM was the same for acoustically similar and acoustically dissimilar words
Therefore LTM primarily makes use of semantic coding
Findings of Jacobs and Miller
(STM capacity)
→ Average span for digits = 9.3 items
→ Average span for letters = 7.3 items
Jacob suggests it is easier to recall digits because there are only 9 of them, whereas there are 26 letters
→ Miller published that the capacity of STM is a range of 5 to 9 pieces of information
→ Miller found that if people can recall 5 words as well as they can recall 5 letters, we chunk things together and can then remember them - process = chunking.
Findings of Sperling
(Sensory register duration)
→ Only 50% available after 0.3 second delay
→ 33% available after 1 second delay
This suggests that the duration of the sensory register is only about 1 second (max)
Findings of Crowder
(Sensory register coding)
→ Iconic information for a few milliseconds
→ Echoic information for 2-3 seconds
This suggests that there are different stores within sensory memory (therefore is not unitary) so different types of coding exist too.
Findings of Sperling
(Sensory register capacity)
→ Recall of letters in indicated row was high (= 76% average)
This suggests that all of the information was originally there, indicating that the capacity of the sensory register, especially for the iconic store, is quite large and therefore potentially unlimited.
What is a retention interval ?
The period between a participants exposure to information and being tested for the retention of the information.
→ So when each trial participants are asked to stop after a different amount of time.
E.g. 3 ,6 ,9 ,12 ,15 or 18 seconds
Purpose of retention interval
Provides empirical evidence for the correlation between duration of memory (STM) and maintenance rehearsal
