Memory: Coding, capacity, duration Flashcards
Capacity
measure of how much can be held in memory
represented in ‘bits’ of info, such as number of digits
Coding
the way info is changed so it can be stored in memory
Types of code
visual code (picture) acoustic code (sound) semantic code (meaning)
Duration
a measure of how long a memory lasts before its not longer available
Researcher who studied coding in STM and LTM
Baddeley
Findings for STM coding (Baddeley)
Immediate recall (STM) was worse with acoustically similar words. Therefore STM is coded acoustically
Findings for LTM coding (Baddeley)
Recall after 20 mins (LTM) was worse with semantically similar words.
Therefore LTM is coded semantically
STM: duration, capacity, coding
18-30 secs
7 +/- 2
acoustic
LTM
unlimited
unlimited
semantic
Why is a lab experiment a strength of Baddeley’s research?
lab experiment = high internal validity due to control of extraneous variables
How can Baddeley’s results be applied to the wider world, specifically in education?
He found we coded semantically in LTM
Enables teachers to improve learning strategies that improve memory in the future
In turn, leads to economic growth in terms of education and training as the future work force able to be more productive because they can retain info for long periods of time.
Why is there limited application for Baddeley’s research
The words were random, no personal meaning. Processing meaningful info may be encoded semantically for STM tasks
Need to be cautious about generalising findings to different types of memory tasks
What is another weakness to Baddeley’s research in addition to limited application
No-one classed LTM as 20 mins. Should be a longer time period
Weakness of Jacob’s study in terms of the date
Early research in psychology lacked control of extraneous variables
Participant may have been distracted, affecting performance
Therefore reduces validity of the study
Findings for Miller (STM capacity)
digit span was 7+/- 2 numbers remembered. Improved by chunking
Procedure for P&P (STM duration)
24 students given consonant trigram to remember
Asked to count back form either 3, 6, 9, 12, 15, or 18.
Procedure for Bahrick
392 Americans ages 17-74
2 separate tests:
1) recognition test: 50 photos recognised from school year book
2) Free-recall test: List names of people from graduation
Researcher who did study involving digit span for capacity of memory
Jacobs (1887)
Procedure for Jacobs (STM capacity)
Digit span. 4 digits read to participants. Increased number until participants couldn’t recall correctly
Researcher who did study involving 7+/- 2 items
Miller
Who conducted research into the duration of STM
Peterson & Peterson
Findings for P&P (STM duration)
3 sec interval = recall 80% correct
18 sec interval = recall 3% correct
Therefore suggests STM lasts 18-30 secs
Weakness for Peterson and Peterson study
Lacks external validity due to artificial stimulus
IRL, dont memorise consonant trigrams
Therefore lacks external validity bc doesn’t reflect how memory works daily
Findings for Bahrick
PP’s tested 48yrs after graduation = 70% accurate in recognition
free recall = less accurate
Findings for Jacobs (STM capacity)
Avg recall: 9.3 numbers 7.3 letters
Evaluation for Miller
Cowen found Miller overestimated
Capacity of STM was about 4 chunks
Lower end of millers 7+/-2 more appropriate (5 items)
Reseacher who investigated LTM
Bahrick
Procedure for Miller (STM capacity)
(STM capacity)
magic number book - observed everything came in 7’s
Procedure for Baddeley
Gave participants a list of acoustically similar/dissimilar words, and semantically similar/dissimilar words.
