COGNITIVE - Memory - Studies Flashcards
Which study looked at the duration of the STM?
Peterson & Peterson
Peterson & Peterson: Method
- Patricipants shown nonsense trigrams
- Asked to recall them after 3,6,9,12,15 or 18 seconds
- During the pause they had to count backwards in threes (interference task)
Peterson & Peterson: Results
After 3 seconds participants could recall about 80% of trigrams correctly
After 18 seconds participants could recall 10% correctly
Peterson & Peterson: Conclusion
When rehearsal is prevented very little can stay in the STM
Peterson & Peterson: Evaluation
- Reliable as it was a lab experiment enables variables to be tightly controlled
- Lacks ecological validity
- Only one type of stimulus was used
- Each participant saw many different trigrams which means the first test might be the only realistic one.
Which study explored very long term memories?
Bahrick et al
Bahrick et al: Method
-392 people asked to recall ex-classmates (free call test). –They were then shown photos and asked to recall thier names (photo recognition test) or given names to match to photos (name-recognition test)
Bahrick et al: Results
Within 15 years of leaving school people would recognise about 90% of names and faces. 60% on free recall test
Within 30 years of leaving school free recall declined to 30%
After 48 years name recognition was 80% accurate and photo recognition 40% accurate.
Bahrick et al: Conclusion
Evidence of VLTM in a ‘real life’ way.
Recognition is better that recall suggesting a huge store of information that is not always easy access.
Bahrick et al: Evaluation
- High ecological validity as it was a field experiment
- Cannot control variables, no way of knowing why information was recalled well
- This type of information can be rehearsed well
- Because of this the results cannot be generalised to other types of info held in the LTM
Which study looked into the capacity of the STM?
Jacobs
Jacobs: Method
- Participants presented with a string of letters or digits.
- They had to repeat them back in the same order until they failed to recall correctly
Jacobs: Results
- Participants recalled around 9 digits and about 7 letters
- Capacity increased with age during childhoods
Jacobs: Conclusion
- STM has a limited capacity of 5-9 items.
- Individual differenced: STM increased with age
- People may use memory techniques such as chunking, making recall easier
Jacobs: Evaluation
- lacks ecological validity as it is an artificial task
- more meaningful information may be recalled better
- previous sequences may have confused the participant
Which study investigated encoding in both the LTM and STM
Baddeley et al
Baddeley et al: Method
- Participants given four sets of words that were wither acoustically similar and different or semantically similar and different
- Using an independent groups design participants had to recall words immediately or 20 minutes later after a task
Baddeley et al: Results
- Participants had problems recalling acoustically similar words immediately from STM
- Recalling from LTM they had problems recalling semantically similar words.
Baddeley et al: Conclusion
Confusion between similar words suggest that the LTM stores semantically and the STM stores acoustically
Baddeley et al: Evaluation
- Lacks ecological validity
- Other methods of encoding that the study does not include
- No control over participant variables
Loftus & Palmer: Method
- Shown a film of a multiple car crash
- Then asked question on the crash
- '’how fast do you think the cars were going when they hit?’’
- In different conditions the word hit was replaced with ‘‘smashed’’ ‘‘collided’’ ‘‘bumped’’ or ‘‘contacted’’
Loftus & Palmer: Results
When the adjective used was more violent a faster speed estimate was given. (average 41 mph) the less violent adjective averages 32 mph
Loftus & Palmer: Conclusion
Leading questions affect the accuracy of people’s memories of events.
Loftus & Palmer: Evaluation
- Artificial did not reflect a real life event.
- May have been effected by demand characteristics. Lowering the validity and reliability