🟣 Memory: coding, capacity, and duration of memory Flashcards
What is short term memory
A memory store that has limited capacity along side a short duration in terms of memory holding
What is long term memory
A memory store that has unlimited capacity along side a with a duration that can last a lifetime
What is coding
The way in which information is kept in the various memory stores
How is information coded in short term memory
Acoustically
How is information coded in long term memory
Semantically
Who was able to discover and show the difference between the two main memory stores (STM + LTM)
Alan Baddeley (1966)
State the weakness of Baddeley’s coding research of STM and LTM
- He used artificial material which had no personal meaning to the participants
- So, Baddeley’s finding may not tell us about different kinds of memory tasks ESPECIALLY in everyday life
- E.g when processing more meaningful information, semantic coding can be used even in the STM
- This shows that Baddeley’s finding of the coding of STM and LTM have limited application
What was a strength is Alan Baddeley’s (1966) coding research
- He was clearly able to distinguish the way in which coding occurred in short term memory and in long term memory
- AND although later research shows there’s from exceptions to Baddeley’s findings, THE idea that STM mainly consists of acoustic encoding and that LTM consists of semantic encoding has NOT CHANGED
- This shows his findings are an important step in our understanding of the memory system AND his finding led to the MSM of memory
What are acoustically similar words
Words that sound similar to each other
What are semantically similar words
Words that have a similar/ the same meaning
What is duration
The length of time in which information can be held in the memory
Who researched the duration of STM
Margaret and Lloyd Peterson (1959)
Who researched the duration of LTM
Harry Bahrick et al (1975)
State the procedure of Bahrick et al’s research on duration of LTM (1975)
- He studied 392 Americans ages 17-74 to test their duration of LTM
- This was tested int two ways
- Photo recognition - using 50 photos (some from the parti’s yearbooks)
- Free recall (remembering their peers names from the yearbooks)
State the findings of Bahrick et al’s research on duration of LTM
- Participants tested w/in 15 years of graduation were 90% accurate in photo recognition AND after 48 years, recall declined to 70% for photo recognition
- For free recall, participants tested w/in 15 years were 60% accurate AND after 48 years, recall dropped to 30%
- This shows LTM lasts up to a lifetime for some material
Describe Baddeley’s (1966) procedure on coding of the STM + LTM
- He put participants into four groups and gave each a different list of words to remember
- Group 1 - got acoustically similar words
- Group 2 - got words that were not acoustically similar
- Group 3 - got words that were semantically similar
- Group 3 - got words that were semantically dissimilar
State the findings of Alan Baddeley’s research on coding of STM + LTM
- When asked to recall information immediately (recalling from STM) - participants in group one struggled recalling the acoustically similar words which shows that STM is coded acoustically
- When asked to recall information 20 minutes later (Recalling from LTM) - participants in group 3 struggled recalling the semantically similar words
- This shows that information is encoded acoustically in the STM and that information is encoded semantically in the LTM
Describe the Petersons research on the duration of STM
- 24 students were tested in 8 trials
- On each trial they were given a consonant syllable and a 3-digit number
- Students were told to count backwards from this 3 digit number to prevent mental rehearsal
- Then on each trial they were told to recall the syllables after 3, 6, 9, 12, 15, and 18 seconds
What was the results of Margaret and Lloyd Petersons research on STM duration
- After 3 seconds on average 80% of information was remembered
- But after 18 seconds the average dropped to 3%
- This suggests that STM duration is 18 seconds unless verbal rehearsal is performed
Who researched capacity of STM (and in what year)
- Jacobs (1887) - Digit span test
- Miller (1956) - Chucking and the capacity of STM (7±2)
Describe the procedure of Jacobs’ research (1887) on the capacity of STM
- Jacobs conducted the digit span test
- Researcher reads out 4 digits and tells a participant to recall it - then does the same with 5 digits and so on until they can no longer remember them in the correct order
State the findings of Jacobs’ research on capacity (1887)
- Mean span for digits was 9.3
- Mean span for letters was 7.3
State Miller’s (1956) observations on the capacity of STM
- He observed and noted that things come in 7’s (e.g 7 notes of a musical scale, 7 days of the week, 7 deadly sins) and from this concluded that the span (i.e capacity of STM is 7±2 items)
- He also mentioned that recalling 5 words can be as easily as recalling 5 letters AND SO memory can be improved by chunking
What is chunking
It is grouping sets of digits or letters INTO units or chunks
Limitation of Margaret and Lloyd Peterson’s research on the duration of STM
- Their stimuli was artificial (made up) and lacked any real meaning to the participants
- AND ALTHOUGH the study was not completely useless as sometimes we memories meaningless materials (e.g phone numbers) - the recall of consonant syllables DOES NOT refer to everyday memory activities
- This shows that the Petersons study lacked external validity
Outline the strength of Bahrick’s et al’s research on the duration of LTM
- The experiment had high external validity
- The researchers investigates meaningful memories of people faces and names that they have encountered
- Furthermore, Shepard (1967) conducted a similar study to Bahrick et al, testing he duration of LTM, but used meaningless pictures. Due to this recall rates lowered
- This shows Bahrick et al’s findings reflected a more ‘legitimate’ estimate of the duration of LTM
Outline the strength of Joseph Jacobs’ research on capacity (1887)
- His study has been replicated.
- Although Jacobs’ study is very old + most early studies lacked adequate control of confounding variables (e.g some participants’ digit span may have been underestimated bc of distractions)
- His study was replicated by Bopp and Verhaegen in 2005 under better control which increases the validity of the digit test span
State a weakness of Joseph Jacobs’ research on capacity (1887)
Initial studies lacked an adequate control
Outline a limitation in Miller’s research on the capacity of the STM (1956)
- He may have overestimated the capacity of the STM
- E.g Nelson (2001) reviewed other research and concluded that the capacity was actually 4±1 items
- This shows that the lower end of Miler’s estimate (5 items) is more appropriate than the higher end of Miller’s estimate (7-9 items)
