Memory- Coding, Capacity and duration Flashcards
What was the research done on coding and its findings?
Alan Baddley gave 4 groups of participants different word lists in both short term and long term recall.
Semantically and acoustically similar and dissimilar words were given.
In the STM recall (immidiate recall), they did worse on acoustically similar words, showing STM is coded acoustically and in LTM recall they did worse on semantically similar words showing LTM is coded semantically.
What is the evaluation of coding?
Disadvantage- uses artificial stimuli, this causes issues in in generalisation and leads to limited application.
What was the research and findings on capacity?
2 studies done, 1 on digit span and one on chunking.
Digit span study: Done by Joseph Jacobs, created a technique to measure digit span ie) increasing digit recall by one each time, until digits can not be recalled in the correct order.
Findings- mean digit span = 9.3 and 7.3 for letters.
Chunking study: Done by George Miller, who noted that people can recall things in 7s so capacity is 7+/- 2. People can recall 5 words just as well as 5 letters due to chunking.
What is the evaluation of the studies on capacity?
Digit Span study by Jacobs- lacked validity due to being done so long ago when confounding variables may not have been correctly controlled.
Chunking study by Miller- Not so many chunks as he recalled, he may have overestimated as Cowan reviewed other research and conducted the mean was around 4 chunks.
What is the research done on duration?
2 studies done. Duration of STM done by Peterson and Peterson and duration of LTM done by Bahrick et al.
Duration of STM by Peterson and Peterson: tested 24 undergraduate students on 8 trials, each of which had them recall a consonant syllable and count back from a 3 digit number they were given to avoid mental rehearsal of the consonant syllable.
Findings- had to stop and recall at retention intervals that went up till 18 seconds, found STM was very short in duration unless constantly repeated.
Duration of LTM by Bahrick et al: studied 392 participants from Ohio aged 17-74 on their highschool in a photo-recognition test of 50 pictures and a free recall of their graduating class.
FIndings- in photo recall 90% accuracy for those who graduated w/in 15 years vs 70% accuracy for those who graduated w/in 48 years. Free recall = 60% for 15 years vs 30% for 48 years. Shows that LTM lasts long indeed.
What is the evaluation of the duration studies?
Peterson and Peterson’s STM study- used meaningless artificial stimuli, so lacks external validity. (Limitation)
Bahrick et al’s LTM study- had high external validity because it studied real life meaningful memories. (Advantage.)
