coding,capacity,duration Flashcards
what is capacity
the amount of information that can be held in a memory store
who studied capacity of STM
- Jacobs
- Miller
what was Jacob’s study of capacity of STM - include method, results, conclusions, evaluations
Method: P’s shown a string of letters or digits. Asked to repeat the strings back in the same order. The number of letters or digits increased until the P was unable to recall the string correctly.
Results: On average, p’s recalled 9 digits or 7 letters. This capacity increased with age during childhood.
Conclusion: STM has a limited storage capacity of 5-9 items. Individual differences found, e.g. STM increasing with age due to memory chunking techniques.
Conclusions: digits may have been easier to recall as there were only 10 diff. digits to remember, compared to 26 letters.
Evaluation: Artificial lacks ecological validity, meaningful info. may be recalled better, ambiguous tasks the previous sequence may have confused p’s.
what was Miller’s study of capacity of STM
Miller (1956) reviewed research into the capacity of STM.
Found people can remember 7 items.
He proposed the capacity of STM was 7 (+/- 2) items (‘Miller’s magic numbers’).
Chunking combines individual letters or numbers into larger, more meaningful units.
E.g. 2,0,0,3,1,9,8,7 is all the digits STM can hold.
Chunked into meaningful info: 2003 1987 it’s easier to remember.
Increases capacity of STM as it can now hold 7 chunks of info.
what is the capacity of LTM
Unlimited
weakness- No research support, How do you test this, you can’t.
what is duration
the length of time information can be held in memory
who studied duration of STM
Peterson + Peterson
what was Peterson + Peterson’s study of duration of STM
Method: P’s were shown nonsense trigrams and asked to recall them either after 3, 6, 9, 12, 15 or 18 seconds. During the pause, they had to count backwards in 3’s from a given number (interference task).
Results: After 3 seconds, P’s could recall 80% of trigrams correctly. After 18 secs, only 10% were recalled correctly.
Conclusion: When rehearsal is prevented, what stays in STM for longer than 18 secs is limited.
Evaluation:
Reliable results, tightly controlled variables, lacks ecological validity (nonsense trigrams), application to real-life (meaningful memories might last longer).
what were the AO3 points for Peterson + Peterson’s study
Reliability
The study conducted by Peterson & Peterson has high reliability.
The experiment was conducted in a lab, in which the variables can be tightly controlled.
Therefore the results obtained from the study are highly reliable, making the study easier to replicate.
Lab experiment
The study conducted by Peterson & Peterson lacks ecological validity.
The experiment was conducted in a lab setting where participants were required to recall nonsense trigrams.
Nonsense trigrams are artificial and therefore the findings cannot be applied to real life settings.
who studied the duration of LTM
Bahrick et al
what was Bahrick et al’s study of duration for the LTM
Investigated VLTM in a natural setting.
Method: 392 American ex-high school students
Asked to list the names of ex classmates (free recall test).
Then shown photos and asked to recall names of people shown (photo-recognition test) or given names and asked to match the name to the photo (name-recognition test).
Results:
Within 15yrs of leaving school, P’s recognised 90% of names and faces.
60% accuracy on free recall. After 30yrs, free recall fell to 30%
After 48yrs, name-recognition had 80% accuracy and photo-recognition was 40%.
Conclusion: Provides evidence of VLTMs in real-life. Recognition is better than recall suggesting, a big store of info that might be hard to access without cues.
Evaluation:
Field experiment
high ecological validity.
Hard to control variables
less reliable findings.
Meaningful info is stored better
Info could be rehearsed (if you’re still in contact with classmates or talk to friends about memories of classmates, increasing rate of recall,
Results can’t be generalised to other types of info held in LTM.
what is coding
how information is stored
who studied coding for STM + LTM
Baddeley
what was Baddeley’s study for coding for STM
Method: P’s given 4 sets of words that were either:
Acoustically similar (e.g. man, mad, mat)
Acoustically dissimilar (e.g. pit, cow, bar)
Semantically similar (e.g. big, large, huge)
Semantically dissimilar (good, hot, pig)
→ Independent groups design. P’s recalled words immediately or after a 20min task
Results: P’s had problems recalling acoustically similar words when recall was immediate (STM). Problems recalling semantically similar words when recall was delayed.
Conclusion: STM to rely on acoustic coding.
Evaluation:
Lacks ecological validity
reductionist (other types of LTM – episodic, procedural and other methods of coding e.g. visual which are ignored
Independent groups design so no control over participant variables.
what was Baddeley’s study for coding for LTM
Method: P’s given 4 sets of words that were either:
Acoustically similar (e.g. man, mad, mat)
Acoustically dissimilar (e.g. pit, cow, bar)
Semantically similar (e.g. big, large, huge)
Semantically dissimilar (good, hot, pig)
→ Independent groups design. P’s recalled words immediately or after a 20min task
Results: P’s had problems recalling acoustically similar words when recall was immediate (STM). Problems recalling semantically similar words when recall was delayed.
Conclusion: Patterns of confusion between similar words suggest LTM is more likely to rely on semantic coding
Evaluation:
Lacks ecological validity
reductionist (other types of LTM – episodic, procedural and other methods of coding e.g. visual which are ignored
Independent groups design so no control over participant variables.
