Coding. capacity & duration

What is coding? AO1

The way in which info is changed & stored in memory

Coding - STM & LTM AO1

• Baddeley

• Participants were asked to recall a list of acoustically or semantically, similar or dissimilar words.

• They had to recall either the words immediately to test STM, or after a 20 minutes, to test LTM.

• Immediate recall was worse for acoustically similar words, indicating that STM relies on acoustic coding, as the similarity in sounds interfered with word storage.

• Delayed recall was worse for semantically similar words, suggesting that LTM relies on semantic coding, as the similarity in meaning disrupted the storage process.

What is capacity? AO1

The maximum amount of info that can be retained in memory

Capacity - STM AO1

• Jacobs

• Participants had to complete the digit span task where they had to immediately recall a sequence of numbers in the correct order

• Sequence length increased after each correct response to measure memory capacity

• Participants could recall on average 9.3 numbers and 7.3 letters.

• Miller

• Found ‘Magic Number’ of average items that could be called to be 7±2

• Can be increased through chunking – grouping information into meaningful units.
  CAPACITY IS LIMITED

Capacity - LTM AO1

• Anokhin found capacity is unlimited

• Info may be lost due to decay & interfernce but losses don’t happen due to limitation of capacity

What is duration? AO1

How long a memory can be held for before it’s forgotten

Duration - STM AO1

•  Peterson & Peterson

• Ppts were asked to recall consonant trigrams after intervals (3,6,9,12,15 or 18 seconds) while doing a distraction task (counting backwards)

• After 3 seconds average accurate recall was 80%.

• After 18 seconds average accurate recall was less than 10%, showing STM has a duration of 18-30 seconds.

Duration - LTM AO1

• Bahrick et al

• 392 ppts aged 17-74 years from USA.

• Ppts took part in a recognition test of naming classmates from a set of 50 photos from high school yearbooks and a free recall test, where they had to recall names from their graduating class without any prompts

• For the recognition test after 15yrs recall accuracy was 90% and after 48yrs recall accuracy was 70%. In the free recall test average accuracy after 15yrs was 60% and after 48yrs it was 30%

• Duration is unlimited & may last a lifetime
  

Badeley AO3

• P - lab experiment

• E - extraneous variables were controlled (eg distractions & noise) to prevent from becoming confounding & affecting recall/results. Eg a standardised word list was used across all participants & each word was shown for same amount of time (approx 3 seconds) to prevent differences in recall due to having more/less time to recall. Standardised instructions to all participants to achieve constituency & avoid bias.

• T - high internal validity & reliability so externally sound to assume coding is acoustic in STM & semantic in LTM

• HOWEVER used artificial, meaningless stimuli of word lists. In real life memory is much more meaningful (like past experiences birthdays etc) & more complex than short word lists. May lack mundane realism & ecological validity

Miller AO3

• P - practical applications

• E- theory has been applied to everyday life as chunking is helpful & used regularly to remember info (eg phone numbers, post codes & bank card numbers). Also used in education & learning techniques to help students learn complex info by breaking into smaller, manageable chunks (eg acrynonms & mnemonics)

• T - theory has been applied to everyday life & is helps people to remember info in STM, meaning Miller’s work has real-world relevance & contributes positively

• HOWEVER research to suggest Miller overestimated. Cowan found that STM capacity is closer to 4±1, not 7±2, which reduces internal validity

Bahrick et al AO3

• P - high ecological validity

• E - used real life-meaningful stimuli as participants had to recall names & recognise faces of former classmates. This contrasts artificial tasks used in many memory studies like Badeley & Peterson & Peterson. Also tested memory over real time intervals (up to 48 years),mirroring real life situations where memory may be used to recall info from distant past

• T - reflects how memory may be used in real life & high mundane realism, meaning findings more realistic & generalisable

• HOWEVER may be confounding variables like participants could’ve looked at year book over the years so recalled more accurately which reduces internal validity