Features of the memory stores | AQA A-Level Psychology Revision
Updated: Sep 9
For specification 7182, first teach in September 2025
AQA A-Level Psychology | Free Revision Notes
Estimated study time: 40 minutes
These Features of the memory stores A-Level Psychology revision notes compare the sensory register, short-term memory and long-term memory in terms of coding, capacity and duration. Each store handles information differently, which helps explain why some information disappears almost immediately while other memories remain available for many years. This lesson develops your understanding of how information travels through the memory system and prepares you to compare the stores accurately in short-answer and extended-response questions.
Learning Objectives 🎯
By the end of this revision page, you should be able to:
Define coding, capacity and duration.
Describe coding, capacity and duration in the sensory register.
Describe coding, capacity and duration in short-term memory.
Describe coding, capacity and duration in long-term memory.
Compare the features of the three memory stores.
Apply the features to examples of remembering and forgetting.
Revision Notes đź“š
Features of the memory stores A-Level Psychology revision overview
The multi-store model describes three separate memory stores:
The sensory register
Short-term memory
Long-term memory
Each store can be described using three features:
Coding
Capacity
Duration
These features allow psychologists to compare how information is represented, how much can be held and how long it can remain available.
What is coding?
Coding is the form in which information is represented within a memory store.
Information may be coded according to:
Its sound.
Its appearance.
Its meaning.
The sense through which it was received.
For example, the word “psychology” could be represented through:
Its sound when spoken.
Its visual appearance on a page.
Its meaning as a subject.
Different memory stores have different main forms of coding.
What is capacity?
Capacity is the amount of information that a memory store can hold at one time.
Capacity can be described through:
The number of separate items held.
The amount of sensory information available.
Whether the store appears to have an upper limit.
A store with limited capacity can hold only a restricted amount before information is lost or replaced.
What is duration?
Duration is the length of time that information can remain within a memory store.
Duration may range from:
A fraction of a second in the sensory register.
Several seconds in short-term memory.
Many years or potentially a lifetime in long-term memory.
Duration is different from capacity. Duration concerns time, while capacity concerns amount.
Quick comparison of the stores
Memory store | Main coding | Capacity | Duration |
Sensory register | Modality-specific | Very large or unlimited | Approximately 250 milliseconds |
Short-term memory | Mainly acoustic | Approximately 7 ± 2 items | Approximately 18 to 30 seconds without rehearsal |
Long-term memory | Mainly semantic | Potentially unlimited | Potentially forever |
The terms mainly acoustic and mainly semantic are important. They indicate the most common form of coding rather than the only possible form.
The sensory register
What is the sensory register?
The sensory register is the first memory store.
It briefly receives information from the environment through the senses. Different forms of sensory information enter different parts of the register.
Examples include:
Visual information entering iconic memory.
Auditory information entering echoic memory.
Tactile information entering a touch-based sensory store.
Only information that receives attention progresses into short-term memory. Most sensory information disappears before conscious processing occurs.
Coding in the sensory register
Coding in the sensory register is modality-specific.
This means that information is coded according to the sensory form in which it was received.
For example:
A colour is represented visually.
A voice is represented auditorily.
A texture is represented through touch.
The sensory register is therefore not a single store using one universal code. It consists of separate sensory systems that retain different types of input.
Iconic memory
Iconic memory is the visual part of the sensory register.
It briefly retains information about:
Colour
Shape
Position
Movement
Visual patterns
For example, after a bright light moves through darkness, a person may briefly experience a visual trace of its path.
Echoic memory
Echoic memory is the auditory part of the sensory register.
It briefly retains sounds after they have been heard.
For example, someone may ask, “What did you say?” but then realise what was said before the speaker repeats it. The auditory trace may have remained available briefly in echoic memory.
Capacity of the sensory register
The sensory register has a very large capacity, often described as unlimited.
At any moment, the senses receive a large amount of information, including:
Images
Sounds
Movements
Textures
Smells
Changes in temperature
The sensory register can receive this broad range of input simultaneously.
However, having a large capacity does not mean that all sensory information becomes a lasting memory. Most information disappears because it does not receive attention.
The key relationship is:
Large sensory capacity + very brief duration = most information is rapidly lost
Duration of the sensory register
The duration of the sensory register is extremely brief.
AQA specimen assessment material describes its duration as approximately 250 milliseconds, which is one quarter of a second.
This allows the brain to retain a very brief trace of sensory information, but the information quickly disappears unless it receives attention.
For example:
A student briefly sees a room number.
The visual information enters iconic memory.
If the student attends to it, it moves into short-term memory.
Without attention, the visual trace quickly disappears.
Research into the sensory register
Sperling investigated the capacity and duration of the visual sensory register.
Participants were briefly shown a grid of letters. When asked to recall the whole grid, they could report only some of the letters. However, participants appeared to have seen more letters than they could report before the image faded.
When a signal immediately indicated which row should be recalled, participants could report letters from the selected row. When the signal was delayed, recall became poorer.
This suggests that:
The visual sensory register has a large capacity.
Its duration is extremely short.
Information fades before all of it can be reported.
Applying sensory-register features
A train information screen changes rapidly. Ben looks away while the new platform number appears and cannot report it a moment later.
The model would explain that:
The number entered Ben’s visual sensory register.
It was coded visually.
The register could receive the information because it has a large capacity.
Ben did not attend to the number.
The brief sensory trace disappeared before it entered short-term memory.
Short-term memory
What is short-term memory?
Short-term memory, or STM, holds information that is currently being consciously processed.
Examples include:
A number being held in mind before it is entered.
The start of a sentence while its ending is read.
A short instruction being followed.
Information being used in a simple calculation.
STM has a more restricted capacity and duration than the sensory register or long-term memory.
The working memory model provides a more detailed account of how short-term mental processing may operate.
Coding in short-term memory
Information in STM is coded mainly acoustically.
Acoustic coding means representing information according to its sound.
This applies even when information is presented visually. A person reading a word may silently convert it into a sound-based form.
For example, when reading the letters:
B, C, D, G, P, T, V
a person may confuse them because their spoken names sound similar.
Research into coding in STM
Baddeley investigated whether sound or meaning affected immediate memory.
Participants learned lists containing words that were:
Acoustically similar.
Acoustically dissimilar.
Semantically similar.
Semantically dissimilar.
Immediate recall was particularly difficult when the words sounded similar.
This suggests that STM relies mainly on acoustic coding. Similar-sounding information is more easily confused because it is represented in a similar form.
Mainly acoustic does not mean only acoustic
STM is described as mainly acoustic rather than entirely acoustic.
People can temporarily retain:
Visual images.
Spatial information.
Meanings.
Sounds.
However, sound-based coding appears particularly important in many immediate verbal-memory tasks.
Do not write that STM can only hold sounds. That claim is too absolute and is inconsistent with the more detailed components of short-term processing.
Capacity of short-term memory
STM has a limited capacity.
A traditional estimate is approximately:
7 ± 2 items
This means that an average person may hold between five and nine separate items in STM at one time.
The estimate concerns separate units of information rather than a fixed number of individual letters or digits in every situation.
Research into STM capacity
Jacobs used a digit-span technique to investigate capacity.
Participants were presented with increasingly long sequences of numbers or letters and asked to repeat each sequence immediately in the correct order.
The longest sequence recalled accurately provided an estimate of STM capacity.
Miller later proposed that the capacity of STM is approximately seven items, plus or minus two.
These findings suggest that STM can hold only a restricted number of units at once.
Immediate recall and capacity
When describing research into STM capacity, the word immediate is important.
A capacity task measures how much information can be held in STM at one time. Participants are therefore normally asked to recall the material immediately or within a very brief period.
If a participant learns information for several days, the task may involve long-term memory rather than only STM capacity.
Chunking
Chunking means combining separate items into larger, meaningful units.
For example, the sequence:
1 9 4 5 2 0 2 6
contains eight separate digits.
It could be reorganised as:
1945 | 2026
The person now needs to retain two meaningful chunks rather than eight unrelated digits.
Chunking does not necessarily increase the number of units STM can hold. Instead, it increases the amount of information contained within each unit.
Applying STM capacity
A person may struggle to remember the sequence:
F B I C I A N H S
as nine separate letters.
They may find it easier to remember:
FBI | CIA | NHS
because the letters have been organised into three familiar chunks.
The number of individual letters remains the same, but the number of units held in STM is reduced.
Capacity varies between people and tasks
The estimate of 7 ± 2 is not a rule that applies identically to everyone.
Capacity may be affected by:
Age
Familiarity with the material
The use of chunking
Whether information is meaningful
Individual differences
The method used to test memory
Use “approximately” when describing STM capacity.
Duration of short-term memory
Without rehearsal, the duration of STM is approximately:
18 to 30 seconds
Information may remain available for longer when it is actively rehearsed.
The duration estimate therefore refers to information that is not continually repeated.
Research into STM duration
Peterson and Peterson investigated how long information remains in STM when rehearsal is prevented.
Participants were given a trigram, which is a three-letter nonsense sequence, such as:
KPL
They were then asked to count backwards from a number. This prevented them from rehearsing the trigram.
Participants attempted to recall the letters after different time intervals.
Recall became poorer as the delay increased, suggesting that information in STM is rapidly lost when rehearsal is prevented.
Why counting backwards matters
Counting backwards was used as a rehearsal-prevention task.
Without it, participants could repeatedly rehearse the letters and maintain them in STM.
A complete description should therefore include:
The trigram.
The counting-backwards task.
The delay before recall.
The decline in recall as the interval increased.
Simply stating that Peterson and Peterson found STM lasts 18 to 30 seconds is not a full
description of how duration was investigated.
Applying STM duration
A receptionist tells Imogen a temporary door code. Before Imogen can repeat it, another person asks her a question. Imogen cannot remember the code half a minute later.
The features of STM can explain this because:
The code entered STM.
Its duration was limited.
The interruption prevented maintenance rehearsal.
The information was no longer available after the delay.
Long-term memory
What is long-term memory?
Long-term memory, or LTM, stores information beyond immediate conscious processing.
Examples include:
Knowledge of psychological theories.
Memories of childhood events.
The meaning of familiar words.
Names of relatives.
Skills learned through practice.
Information revised for an examination.
Information in LTM must be retrieved into STM when it is consciously used.
Coding in long-term memory
Information in LTM is coded mainly semantically.
Semantic coding means representing information according to its meaning.
For example, a student may remember that:
Attention transfers information into STM.
Rehearsal helps transfer information into LTM.
Retrieval brings information back into conscious awareness.
The exact wording may be forgotten while the meaning remains.
Research into coding in LTM
Baddeley’s word-list research also investigated long-term coding.
Following a delay, recall was particularly difficult for words with similar meanings.
This suggests that LTM relies mainly on semantic coding. Information with similar meanings may be confused because it is represented semantically.
LTM is not exclusively semantic
Long-term memories may also contain:
Visual information.
Auditory information.
Emotional information.
Motor information.
Spatial information.
The statement that LTM is mainly semantic describes a common pattern in research using verbal material. It does not mean that every long-term memory is stored only through meaning.
This is one reason why the strengths and limitations of separate memory stores require careful discussion.
Capacity of long-term memory
The capacity of LTM is considered potentially unlimited.
People can accumulate large amounts of:
Knowledge
Experiences
Skills
Personal information
Vocabulary
Facts
Familiar routines
There is no clearly established point at which LTM becomes completely full and can accept no further information.
Unlimited capacity does not mean perfect memory
A potentially unlimited capacity does not mean that every experience is remembered accurately.
Information may be:
Encoded poorly.
Difficult to retrieve.
Changed over time.
Affected by other memories.
Forgotten despite remaining somewhere in storage.
The amount that can potentially be stored is different from how accurately or easily information can later be recalled.
Duration of long-term memory
The duration of LTM is potentially permanent or potentially forever.
Some information may remain available for:
Days
Months
Years
Decades
An entire lifetime
The word potentially is important. Not every memory lasts forever, but LTM is capable of retaining information for extremely long periods.
Research into LTM duration
Bahrick and colleagues investigated long-term memory for former classmates.
Participants were tested on information such as:
Recognising photographs.
Matching names with photographs.
Recalling names.
Some participants had left school many years earlier but could still recognise former classmates accurately.
This suggests that meaningful information can remain in LTM for several decades.
Why meaningful information may last
Memories of former classmates differ from artificial word lists because they may have been:
Encountered repeatedly.
Connected to personal experiences.
Emotionally meaningful.
Used over several years.
Supported by photographs and other retrieval cues.
This increases the everyday relevance of the research, although it also makes it difficult to control exactly how often each memory was rehearsed.
Applying LTM duration
Sixty-year-old Ava remembers the name of a teacher who taught her when she was eleven.
This suggests long-term memory because:
The information has remained available for several decades.
Its duration is far longer than the limits of STM.
The teacher’s name may have been stored semantically and connected with meaningful experiences.
Stored does not always mean retrievable
A person may fail to recall information even when it has been stored in LTM.
For example, someone may be unable to remember a former classmate’s name but recognise it immediately when shown a list.
This suggests a difference between:
Availability, whether the information is stored.
Accessibility, whether the information can be retrieved at that moment.
This distinction is developed through the absence of effective retrieval cues.
Comparing the three stores
Comparison by coding
Store | Main form of coding | Example |
Sensory register | Modality-specific | A face is coded visually and a voice auditorily |
STM | Mainly acoustic | A code is silently repeated according to its sound |
LTM | Mainly semantic | A theory is remembered through its meaning |
The sensory register preserves the original sensory form.
STM often represents verbal information through sound.
LTM often represents verbal information through meaning.
Comparison by capacity
Store | Capacity |
Sensory register | Very large or unlimited |
STM | Limited, approximately 7 ± 2 items |
LTM | Potentially unlimited |
The sensory register can receive a large amount of immediate input, but almost all of it disappears quickly.
STM holds only a small amount in conscious awareness.
LTM can retain a vast amount of accumulated information.
Comparison by duration
Store | Duration |
Sensory register | Approximately 250 milliseconds |
STM | Approximately 18 to 30 seconds without rehearsal |
LTM | Potentially forever |
Duration increases considerably across the three stores:
Fraction of a second → several seconds → potentially a lifetime
Complete comparison table
Feature | Sensory register | Short-term memory | Long-term memory |
Purpose | Briefly receives sensory input | Holds information in conscious awareness | Retains information for later use |
Coding | Modality-specific | Mainly acoustic | Mainly semantic |
Capacity | Very large or unlimited | Approximately 7 ± 2 items | Potentially unlimited |
Duration | Approximately 250 milliseconds | Approximately 18 to 30 seconds without rehearsal | Potentially forever |
Example | Brief visual trace of a sign | Holding a number before entering it | Remembering a theory in an examination |
Applying all three stores to one situation
Consider the following scenario:
Leah sees a new password on a screen. She reads it aloud several times and uses it to sign in. Months later, she remembers the meaning of the phrase used in the password but cannot reproduce every symbol accurately.
Sensory register
The password first enters Leah’s iconic memory because it is presented visually.
The sensory register codes it according to its visual form and holds it very briefly.
Short-term memory
Leah attends to the password, transferring it into STM.
By reading it aloud, she represents and rehearses it acoustically. STM holds only a limited number of units, so chunking the password into meaningful sections may help.
Long-term memory
Continued rehearsal may transfer the password into LTM.
Its meaning may be stored semantically, explaining why Leah later remembers the phrase but not every exact visual detail.
Using comparative wording
When asked to compare the stores, do not write three unrelated descriptions.
Use phrases such as:
“Whereas”
“In contrast”
“Compared with”
“Both”
“Unlike”
“Longer than”
“More limited than”
For example:
STM has a limited capacity of approximately 7 ± 2 items, whereas LTM has a potentially unlimited capacity.
This directly answers the command word compare.
Weak comparison
STM codes acoustically. LTM codes semantically.
This contains relevant facts but does not explicitly compare them.
Stronger comparison
STM codes information mainly according to sound, whereas LTM codes information mainly according to meaning.
The second version makes the difference clear.
How the features relate to forgetting
Sensory-register forgetting
Sensory information disappears rapidly when it does not receive attention.
Its large capacity does not prevent forgetting because its duration is extremely short.
STM forgetting
Information in STM may be lost because:
Its duration is limited.
Rehearsal is prevented.
Capacity is exceeded.
Attention is diverted.
Information can also be affected by other incoming material.
LTM forgetting
LTM has a potentially unlimited capacity and duration, but information may still become difficult to recall.
This may occur because:
Other memories compete with it.
Suitable retrieval cues are absent.
The information was not encoded effectively.
Recall is less sensitive than recognition.
These processes are examined further through how memories compete with one another and retrieval failure.
Important qualifications
Main coding is not exclusive coding
It is too simplistic to state that:
STM only uses sound.
LTM only uses meaning.
The evidence suggests that acoustic and semantic codes are particularly important, but memory can use more than one form of representation.
Capacity estimates are approximate
STM capacity differs according to:
The individual.
The material.
Familiarity.
Chunking.
The testing procedure.
The estimate of 7 ± 2 should therefore be presented as approximate.
Duration depends on rehearsal and meaning
The 18-to-30-second estimate for STM applies when rehearsal is prevented.
Long-term duration may be greater for meaningful, repeatedly encountered information than for artificial material learned once.
Memory tests measure different things
Psychologists can test memory using:
Recall, producing information without it being presented.
Recognition, identifying previously encountered information.
Relearning, measuring how quickly information is learned again.
Someone may fail a recall test but succeed at recognition. This can produce different estimates of how long information remains available.
Hints from the Examiner Reports đź’ˇ
Examiner hint:Â Learn coding, capacity and duration as three separate features. Students sometimes confuse capacity with duration, especially when describing short-term memory.
Examiner hint: Use precise figures where appropriate. STM has a capacity of approximately 7 ± 2 items and a duration of approximately 18 to 30 seconds without rehearsal.
Examiner hint: Include the word immediate when describing a digit-span investigation. Immediate recall helps show that the task is measuring short-term capacity.
Examiner hint:Â When describing how STM duration is investigated, explain the method rather than only stating the conclusion. Relevant details include trigrams, counting backwards to prevent rehearsal and delayed recall.
Examiner hint: Distinguish between “mainly” and “only”. STM is coded mainly acoustically and LTM mainly semantically, but neither store is restricted to a single form of coding.
Examiner hint:Â For comparison questions, use explicit comparative language. Three separate descriptions may not fully address the instruction to compare.
Examiner hint:Â Match the content to the command word. If asked to describe a method, give procedural detail. If asked to state a feature, do not use valuable time writing an extended evaluation.
Common Mistakes ⚠️
Mistake: Confusing coding with capacity
Why this is incorrect:
Coding concerns the form of information. Capacity concerns how much information can be held.
How to improve:
Remember:
Coding = form
Capacity = amount
Duration = time
Mistake: Saying that the sensory register has a small capacity
Why this is incorrect:
The sensory register can receive a very large amount of information. Its main limitation is its extremely brief duration.
How to improve:
State that it has a large or unlimited capacity but lasts only a fraction of a second.
Mistake: Saying that all sensory information reaches STM
Why this is incorrect:
Only attended information progresses beyond the sensory register.
How to improve:
Link the large capacity of the sensory register with the selective role of attention.
Mistake: Saying that STM codes only acoustically
Why this is incorrect:
Acoustic coding is the main form identified in many verbal-memory tasks, but STM can also process other types of information.
How to improve:
Use the phrase mainly acoustic.
Mistake: Describing STM capacity as exactly seven items
Why this is incorrect:
The traditional estimate is approximately seven items, plus or minus two. Capacity also varies between people and tasks.
How to improve:
Write approximately 7 ± 2 items.
Mistake: Saying chunking gives STM an unlimited capacity
Why this is incorrect:
Chunking makes each unit contain more information. It does not remove STM’s capacity limit.
How to improve:
Explain that chunking reduces the number of separate units that must be retained.
Mistake: Saying STM always lasts 30 seconds
Why this is incorrect:
The estimate applies when rehearsal is prevented. Rehearsal can keep information active for longer.
How to improve:
Write approximately 18 to 30 seconds without rehearsal.
Mistake: Omitting the counting-backwards task from Peterson and Peterson
Why this is incorrect:
Counting backwards prevented participants from rehearsing the trigram. Without this detail, the method is incomplete.
How to improve:
Explain how rehearsal was prevented and why this allowed duration to be measured.
Mistake: Saying LTM is coded only semantically
Why this is incorrect:
Meaning is the main code identified in verbal research, but long-term memories can also contain visual, auditory and other information.
How to improve:
Use the phrase mainly semantic.
Mistake: Saying unlimited capacity means perfect memory
Why this is incorrect:
A store may have a very large capacity while retrieval remains inaccurate or unsuccessful.
How to improve:
Distinguish how much can be stored from how easily it can later be recalled.
Mistake: Writing three descriptions without comparing them
Why this is incorrect:
The command word compare requires similarities or differences to be made explicit.
How to improve:
Use comparative connectives such as “whereas”, “unlike” and “in contrast”.
Exam-Style Questions ✍️
Question 1
Which one of the following correctly describes the main form of coding in long-term memory?
A. Acoustic
B. Semantic
C. Modality-specific
D. Visual only
[1 mark]
reveal mark scheme and indicative content
Answer: B. Semantic
Question 2
Define each of the following:
Coding
Capacity
Duration
[3 marks]
reveal mark scheme and indicative content
Mark scheme
AO1 = 3
Award 1 mark each for:
Coding:Â the form in which information is represented or stored in memory.
Capacity:Â the amount of information that can be held in a memory store.
Duration:Â the length of time information can remain in a memory store.
Example answer
Coding is the form in which information is stored. Capacity is the amount of information a memory store can hold. Duration is how long information can remain in the store.
Question 3
Complete the table below.
Store | Coding | Capacity | Duration |
Sensory register | Modality-specific | A | Approximately 250 milliseconds |
Short-term memory | B | Approximately 7 ± 2 items | C |
Long-term memory | D | E | Potentially forever |
[5 marks]
reveal mark scheme and indicative content
Mark scheme
AO1 = 5
Award 1 mark for each correct answer.
Letter | Answer |
A | Unlimited / very large |
B | Acoustic |
C | Approximately 18–30 seconds |
D | Semantic |
E | Unlimited |
AQA's specimen mark scheme gives the sensory register capacity as unlimited, STM duration as 18–30 seconds, STM coding as acoustic, and LTM coding as semantic.
Question 4
Outline the coding, capacity and duration of the sensory register.
[4 marks]
reveal mark scheme and indicative content
Mark scheme
AO1 = 4
Award marks for:
1 mark:Â coding is modality-specific.
1 mark:Â different sensory information is coded according to its sensory form, such as visual or auditory.
1 mark:Â capacity is very large/unlimited.
1 mark:Â duration is extremely brief, approximately 250 milliseconds.
Example answer
The sensory register uses modality-specific coding, so information is stored according to the sense through which it enters. Its capacity is very large or unlimited, but its duration is extremely short, approximately 250 milliseconds.
Question 5
Explain two differences between short-term memory and long-term memory.
[4 marks]
reveal mark scheme and indicative content
Mark scheme
AO1 = 4
For each difference:
2 marks for a clear and explicit comparison.
1 mark for a limited or incomplete comparison.
Indicative content
STM is mainly acoustically coded, whereas LTM is mainly semantically coded.
STM has a capacity of approximately 7 ± 2 items, whereas LTM capacity is effectively unlimited.
STM lasts approximately 18–30 seconds without rehearsal, whereas LTM may last potentially forever.
Example answer
STM mainly codes information acoustically, whereas LTM mainly codes information semantically. STM also has a limited capacity of about 7 ± 2 items, whereas the capacity of LTM is effectively unlimited.
Question 6
A researcher reads increasingly long sequences of digits to each participant. After every sequence, the participant immediately repeats the digits in the correct order. The researcher records the longest sequence each participant recalls accurately.
Explain which feature of memory is being investigated and why immediate recall is important.
[4 marks]
reveal mark scheme and indicative content
Mark scheme
AO2 = 4
Award 1 mark each for:
Identifying capacity of STMÂ as the feature being investigated.
Increasing sequence length allows the researcher to establish the participant's digit span.
The longest accurately recalled sequence indicates the amount STM can hold.
Immediate recall reduces the opportunity for information to enter LTM, so performance reflects STM capacity.
Example answer
The researcher is investigating the capacity of short-term memory. Increasing the number of digits until the participant can no longer recall them measures their digit span. Immediate recall is important because the digits should still be in STM rather than having been stored in long-term memory.
AQA has previously credited the digit-span technique for investigating STM capacity and stressed the importance of immediate recall.
Question 7
A participant is shown a three-letter sequence and is then asked to count backwards for different lengths of time before recalling it.
Explain how this procedure could be used to investigate the duration of short-term memory.
[4 marks]
reveal mark scheme and indicative content
Mark scheme
AO2 = 4
Award 1 mark each for:
The three-letter sequence is held in STM.
Participants recall it after different time intervals.
Counting backwards prevents maintenance rehearsal.
The point at which accurate recall substantially declines indicates the duration of STM.
Example answer
The three-letter sequence is placed in short-term memory and recall is tested after different delays. Counting backwards prevents participants rehearsing the letters. If recall becomes poorer as the delay increases, the researcher can estimate how long information remains in STM without rehearsal.
AQA accepts the trigram and backwards-counting procedure as a way of investigating STM duration, with recall tested within about 30 seconds.
Question 8
Nadia reads a temporary code and silently repeats it until she has entered it. Several years later, she can still remember the meaning of a poem she learned at school but cannot reproduce its exact wording.
Use your knowledge of coding and duration to explain Nadia’s memories.
[6 marks]
reveal mark scheme and indicative content
Mark scheme
AO2 = 6
Award credit for effective application of coding and duration.
Indicative content
Temporary code
Held in STM.
Likely to be coded mainly acoustically as Nadia silently repeats it.
STM has a short duration, so it is lost after rehearsal stops.
Poem
Stored in LTM.
LTM can last for years or potentially a lifetime.
Remembering the meaning rather than exact wording is consistent with semantic coding.
Example answer
The temporary code is held in Nadia's short-term memory and is likely to be coded acoustically as she silently repeats it. Rehearsal keeps it available temporarily, but STM has a short duration, so she forgets it after she stops rehearsing. The poem has been stored in long-term memory, which can last for many years. Her ability to remember its meaning rather than its exact wording is consistent with the mainly semantic coding of LTM.
Question 9
A psychologist investigated immediate recall of word lists.
Type of word list | Mean number recalled correctly |
Acoustically similar | 4.1 |
Acoustically dissimilar | 7.8 |
Semantically similar | 7.3 |
Semantically dissimilar | 7.5 |
Describe the pattern shown in the results. Explain what the findings suggest about coding in short-term memory.
[4 marks]
reveal mark scheme and indicative content
Mark scheme
AO2 = 4
Award 1 mark each for:
Recall is much lower for acoustically similar words, 4.1, than acoustically dissimilar words, 7.8.
Semantic similarity has little effect, 7.3 compared with 7.5.
Immediate recall is primarily testing STM.
The findings therefore suggest STM codes information mainly acoustically.
Example answer
Participants recalled far fewer acoustically similar words, 4.1, than acoustically dissimilar words, 7.8. In contrast, there was very little difference between semantically similar and dissimilar lists, 7.3 and 7.5. Because recall was immediate, the task mainly measured STM. The strong effect of acoustic similarity therefore suggests that STM primarily uses acoustic coding.
This pattern reflects the type of finding AQA credits from Baddeley's coding research, where immediate recall of acoustically similar words was poorer than recall of acoustically dissimilar words.
Question 10
Discuss the coding, capacity and duration of the sensory register, short-term memory and long-term memory.
[16 marks]
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