memory- coding capacity and duration Flashcards
who was the main person to study coding of memory?
Baddeley (1966)
what was the procedure of Baddeley for coding of memory?
-ACOUSTICALLY similar words (e.g. cat, cab, can) or dissimilar (e.g. pit, few, cow)
-SEMANTICALLY similar words (e.g. great, large, big) or dissimilar (e.g. good, huge, hot)
what was the findings of Baddeley for coding of memory?
-immediate recall worse w/ acoustically similar. STM acoustic
-recall after 20 minutes worse w/semantically similar words. LTM semantic
who was the person to study capacity of memory w/digit span?
Jacobs (1887) testing digit span
what was the procedure of Jacobs for capacity of memory?
-researcher reads four digits and increases until p’s cannot recall order correctly. final number= digit span
what was the findings of Jacobs for capacity of memory?
-on average could repeat back 9.3 numbers and 7.3 letters in correct order immediately after presented
who was the person to study capacity of memory w/ magic number?
Miller (1956)
what was the procedure of Miller for capacity of memory?
-observed everyday practice
-noted things come in sevens- notes of musical scale, days of week, deadly sins, etc
what was the findings of Miller for capacity of memory?
-span of STM about 7 items (+/-2)
-increased by chunking- grouping sets of digits/letters into meaningful units
who were the people to study the duration of STM?
Peterson and Peterson (1959)
what was the procedure of Peterson and Peterson for duration of STM?
24 students were given a consonant syllable (e.g. YCG) to recall and a 3-digit no. to count backwards from. the retention interval was varied 3, 6, 9, 12, 15 or 18 seconds
what was the findings of Peterson and Peterson for duration of STM?
-after 3s- average recall was ab 80%. after 18s it was about 3%. STM duration without rehearsal is up to 18s.
who studied duration of LTM?
Bahrick et al. (1975)
what was the procedure of Bahrick et al. for capacity of LTM?
-392 Americans aged 17-74
1. recognition test- 50 photos from high school year books
2. free recall test- p’s listed names of their graduating class
what was the findings of Bahrick et al. for capacity of LTM?
- recognition test- 90% accurate after 15 years, 70% after 48 years
- free recall test- 60% recall after 15 years, 30% after 48 years
ao3 of Baddeley- two memory stores
-exceptions to Baddeley’s findings
-STM mostly acoustic, LTM mostly semantic
-led to development of MSM
ao3 of Baddeley- artificial stimuli
-words had no personal meaning to p’s so tells us little ab coding for everyday memory tasks
-when processing more meaningful info, people use semantic coding even for STM
-findings of this study have limited application
ao3 of Jacobs- replicated
-old study, may have lacked adequate controls (confounding variables e.g. p’s being distracted)
-despite this findings have been confirmed in layer controlled studies (e.g. Bopp and Verhaeghen 2005)
-shows Jacob’s study a valid measure of STM digit span
ao3 of Miller- overestimate STM capacity
-Cowan (2001) reviewed other research
-concluded capacity of STM only about 4 (+/-1) chunks
-suggests lower end of Miller’s estimate more appropriate than 7 items
ao3 of Peterson and Peterson- meaningless stimuli
-sometimes try to recall meaningless things so study is not completely irrelevant
-but recall of consonants syllables doesn’t reflect meaningful everyday memory tasks
-so study lacks external validity
ao3 of Bahrick et al - high external validity
-everyday meaningful memories studied (e.g. people’s faces)
-when lab studies done with meaningless pictures recall dates were lower (e.g. Shepard 1967)
-findings reflect a ‘real’ estimate of the duration of LTM
