memory

multi-store model

1968 Atkinson and Shiffrin.

Baddeley 1968 coding

coding- tested if LTM or STM encodes acoustically or semantically(meaning)

ppts 4 trials at learning order of words. 20 min delay to remove stm then ppts recalled words in order. compared 5th trial with 4th 20 mins before. he added an interference task in between.

to test STM they were asked to recall immediately.

findings:

stm was helping LTM out

LTM ppts struggles with similar semantic words

STM ppts struggled with acoustically similar words

Conclusions:

STM uses acoustic encoding

LTM uses semantic encoding

+

high control and standardised

-

lacks ecological validity

poor mundane realism

study on capacity of STM

Jacobs digit span. PPTS asked to recall digits in specific order. on average ppts could remember 7 digits.

study on length of STM

Peterson and Peterson to test how long STM lasts without rehearsal

ppts briefly shown trigram of three consonants

then given interference task

after intervals ppts asked to recall.

90% recal after 3 seconds

then got worse at 18s only 2-3%.

DURATION IS 13 seconds 20 at most.

Study of LTM capacity and duration

Linton 1985 woman

6 years made a diary of 5000 events

she could recall events and dates each month

so LTM has endless capacity and long term duration.

Study on high school yearbooks

Bahrick et al

392 graduates shows photos from yearbook.

1 condition they had to match a list of names to photos

90% correct after 14 years, 80% after 34yrs

another condition names ppts in a photo without list of names

60% accurate after 7 years

less than 20% after 47 years

Conclusion

people can remember certain information types for a life time. But the accuracy is high in recognition than recall.

types of LTM

episodic - ability to recall events. Time stamped and chronological

semantic- Knowledge of the world. Facts and concepts.

procedural- memory for actions and skills. Muscle memory

proved through clive wearing as his procedural memory still worked.

Working memory model

Baddeley and Hitch (1974)

proved by Baddeleys dual task technique. tasks usuing diffrent components could be completed whereas same part were hard.

WMM evaluation

Research support

Baddeley et al 1975 found that ppts found it harder to remember long lists of words compared to short lists of words. This supports the idea of the phonological loop.

Practical Application helps us understand mental disorders such as ADHD which are linked to stm

Lack of detail on central executive. research suggests it might have multiple components.

interference

explanation for forgeting

P roactive

O ld interferes with new

R etroactive

N ew interferes with old

interference evaluation

Henk Schmidt 2000 - retroactive

Remembering childhood street names

Positive association with number of times moved house outside the neighbourhood and the number of street names forgotton.

-Not a full explanation - explains what happens not the cognitive processes causing this

+support for Proactive - Keppel and Underwood found recall of older trigrams was harder than new trigrams

-lab study + controlled -artificial situation

Retrieval failure

Lack of accessibility rather than availibility of memory.

This may be due to insufficient cues to remember.

study on retrieval failure

Baddeley and Godden 1975 Asked to learn words on land and underwater.

Memory was 40% better when words were recalled in the same place.

retrieval failure evaluation

practical application

research support

--

Retrieval effects might be different in real life to experiment. EG environment change may be not so extreme so situation might not effect retrieval very much.

study on leading questions (eyewitness testimony)

Loftus and Palmer (1974) 45 american students watched clips of car accidents

when question was hit/smashed estimated speed was greater than collided/bumped etc

-lacks mundane realism as its not the same is witnessing a real car accident

+easy to replicate and controlled

+ethically sound

Post Event discussion

memories become distorted with false information

study supporting post event discussion

Gabbert 2003 71% of witnesses who carried out Post event discussion had inaccuracies.

-lab experiment

-Individual differences in age children under 12 most sucseptable to post event discussion, adults over 60 also more susceptable due to cognitive decline

Anxiety affecting EWT

Depending on the incident the witness may have been scared and this may have affected the accuracy.

Very low anxiety causes low levels of accuracy

As anxiety increases accuracy increases

then if anxiety is too high accuracy decreases again

Supporting research for anxiety

Johnson and Scott 1976

shown 2 conditions an argument where knife walks out the room or a conversation where man walks out with pen and greasy hands.

found lower accuracy in high anxiety situation due to weapon focus affect

improving accuracy of EWT

cognitive interview technique

Change recall order

Recall from different perspective

Context reinstatement (say how you feel and what there is etc)

Report everything

Fisher developments

minimise distractions

make eye contact

encourage witness to speak slowly

ask open ended questions