Memory Studies

Basic outline of the studies in Memory including the procedure, findings, conclusions, strengths and weaknesses.

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  • Created by: Rajvir
  • Created on: 11-05-14 10:53

Peterson and Peterson - Duration of STM

Procedure

- Briefly shown many 3 letter trigrams - given interference task of counting backwards in 3's
- After intervals of 3,6,9,12,15 and 18 seconds, they were asked to recall original trigrams

Findings

- Able to recall 80% of trigrams after 3 seconds
- As the time spent on the interference task increased, the fewer trigrams were remembered
- After 18 seconds less than 10% of trigrams were recalled

Conclusion

- If rehearsal is prevented then info vanishes from STM - STM has a limited duration of 18 secs

Strengths

- Highly controlled - determine cause and effect - EVs are minimised - standardised procedures

Weaknesses

- Lacks mundane realism and ecological validity - trigrams are not the type of info we need to remember in real life situations - artificial - harder to generalise

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Bahrick - Duration of LTM

Procedure

- 392 graduates of American high school tested for their memory of former classmates
- Used various memory tests - free recall, cued recall of matching names to pictures, recognition of pictures

Findings

- Performance was remarkably well up to about 34 years
- Performance better on recognition tasks than recall tasks
- Dip in performance on all memory tasks after 47 years

Strengths

- High mundane realism - findings easier to generalise

Weaknesses

- Difficult to decide whether missing material was due to passage of time or ageing effects
- EVs present - harder to decipher cause and effect

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Jacobs - Capacity of STM

Procedure

- Read aloud lists of monosyllabic letters or numbers
- Increased the number of items until participants could only remember 50%

Findings

- Capacity of STM is limited to 7 items but between 5 and 9 is not unusual
- Miller said capacity can be increased by chunking
- Simon said capacity is affected by pronunciation time

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Baddeley - Encoding of STM

Procedure

- Asked to recall immediately after the presentation of a list of 5 words
- 2 conditions - one group has acoustically similar words (e.g. man, map, cat) and other group had acoustically dissimilar words (e.g. kit, pet, toe)

Findings

- Participants remembered LESS of the acoustically similar words than acoustically dissimilar words due to confusion as STM prefers to encode in terms of sound

Conclusion

- STM encodes acoustically

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Baddeley - Encoding of LTM

Procedure

- Asked to recall lists of 10 items after a 20 minute delay
-
2 conditions - one had semantically similar words (e.g. big, large, great) and other had semantically dissimilar words (e.g. late, old, cry)

Findings

- Participants remembered LESS of the semantically similar words than the semantically dissimilar words due to confusion as LTM prefers to encode in terms of meaning

Conclusion

- LTM codes semantically

Weaknesses

- Study only tested memory for lists of words - findings can't be generalised to other types of memory

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Baddeley - Evidence for the Visuospatial Sketchpad

Procedure

- Participants given 2 tasks to perform at the same time that used visual processing
- Task 1: track moving light. Task 2: describe and trace shape of letter
- Another group performed 2 tasks using 2 different slave systems
- Task 1: track moving light. Task 2: verbal task involving talking only

Findings

- 2 visual tasks difficult - involved using same slave system - limited capacity
- Completed 1 visual task and 1 verbal task with no problem - used 2 different parts of WMM

Conclusion

- Memory has 2 different stores that process different types of information simultaneously

Strengths

- Highly controlled - determine cause and effect
- Repeated measures design - limits individual differences - valid
- Supports WMM

Weaknesses

- Lacks mundane realism - artificial tasks - not true to real life - hard to generalise - lacks eco validity

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Loftus 1 - Misleading post event information

Procedure

- Showed a film of events leading up to car accident
- Control group: asked questions with what they actually had seen (stop sign)
- Experimental group: asked questions with misleading info (barn)

Findings

- 17% of experimental group reported seeing barn, 3% control group reported seeing barn

Conclusions

- Some participants absorbed misleading info - effected their original memory

Strengths

- Lab experiment - high control - same standardised procedure - cause and effect - realistic material - more mundane realism - can generalise findings

Weaknesses

- Demand characteristics - lack validity fully informed consent not given - deceived them -debrief
- Situation was artificial - aware they had to pay attention to film - not completely valid

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Loftus 2 - Misleading post event info + rewards

Procedure

- Offered money rewards if participants correctly recalled details from film accident
- One group saw pedestrian knocked over at stop sign, one group saw yield sign
- 2 days later, questioned about this however...
  * participants who saw STOP sign were questionned about a YIELD sign
  * participants who saw YIELD sign were questionned about a STOP sign
- Asked participants to look at 2 images and point out which had been in the original film

Findings

- 70% made an error on image identification due to the misleading information they had been told in critical question

Conclusions

- Original memory is altered as a result of misleading post event information

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Loftus 3 - Misleading post event info + 'a' & 'the

Procedure

- Participants were shown a clip of a car accident and asked a series of questions
- One group: asked if they had seen 'A' broken headlight
- Other group: asked if they had seen 'THE' broken headlight
- NO BROKEN HEADLIGHT IN THE FILM

Findings

- 17% reported seeing a broken headlight if THE was used
- 7% reported seeing a broken headlight is A was used

Conclusions

- Minor differences in the wording of a question can influence witness recall

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Loftus 4 - Misleading post event info +verb change

Procedure

- Showed participants a clip of a car accident and asked a series of questions
- One crucial question concerned the speed of the car on impact
- One group asked: 'how fast were the cars going when they HIT each other?'
- Other group asked: 'how fast were the cars going when they SMASHED/BUMPED/COLLIDED?'

Findings

- Verb used significantly affected the speed estimates where 'smashed' was the highest estimate and 'contacted' had the lowest estimate
- A week later, participants were questionned again and those with 'smashed' version were more likely to report broken glass (even when there was none)

Conclusions

- Minor differences in the wording of a question can influence witness recall

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Flin - Age and Eyewitness Testimony

Procedure

- Questionned children and adults one day after an incident and then again after 5 months

Findings

- There was no differences in the amount of accuracy and recall after a day
- Children forgot a lot after 5 months

Conclusions

- Children are more vulnerable to time delay and interference

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Gordon - Age and Eyewitness Testimony

Procedure

- Review of child witness research

Conclusions

- Young children can provide detailed and accurate witness statements
- Children are particularly susceptible to suggestion and their accounts should be viewed with caution

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Davies - Age and Eyewitness Testimony

Conclusion

- Believes some of the differences between child and adult witnesses have been overstated
- Children can provide valuable testimony provided care is taken in the interviewing process

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Yarney - Age and Eyewitness Testimony

Procedure

- Elderly and young adult participants
- Asked questions about a staged event

Findings

- 80% of elderly participants failed to mention the attacker had a knife
- 20% of young adults failed to mention the attacker had a knife

Conclusions

- Elderly notice less detail

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Cohen & Faulkner - Age and Eyewitness Testimony

Procedure

- Showed a film of kidnapping to groups of middle aged and elderly participants
- One group read narrative account of the scene witnessed, other group read a narrative account containing misleading information

Findings

- In a recall test, elderly were found to be more susceptible to the effects of misleading information

Conclusions

- Elderly were more vulnerable to misleading information

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Poole and Lindsay - Age and Eyewitness Testimony

Procedure

- Field experiment - children aged 3-8 - shown science demonstration - parent then read child a book involving some info from demonstration and novel info - children questionned about demonstration - asked where they got their info from

Findings

- Older children were better at recognising where they got the info from whereas younger children couldn't source their information very well - Children's EWT is affected by post event info

Strengths

- High eco validity - real life situation - high mundane realism - involved family - children at ease - no investigator effects - can generalise

Weaknesses

- Younger children couldn't give informed consent - parents - EVs = unsure of cause and effect

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Loftus - Weapon Effect

Procedure

- Participants sat outside a lab - thought they were hearing a genuine exchange between people inside the lab
- One condition: heard amicable discussion about equipment failure. Man with greasy hands came out holding a pen
- Other condition: heard hostile discussion and sound of breaking glass and overturned furniture. Man came out with a knife covered in blood
- Gave 50 photos and asked to identify the man who came out of the lab

Findings

- Accurate recall of identifying the man holding the pen -> 49%
- Accurate recall of identifying the man holding knife -> 33%
- In a follow up, Loftus recorded eye movement and found the focus of attention was on the knife which diverted attention from the identity of the man

Conclusions

- Seeing a weapon detracts from what is going on - reduces accurate recall

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