memory - research studies on coding, capacity and duration Flashcards
define coding
- how we process information to a suitable form so it can be stored
- e.g. STM = codes acoustically
define capacity
- how much information can be held in memory
- e.g. STM = 5-9 items
define duration
- how long information can be held in memory
- e.g. STM = 18-30 seconds
sensory register coding
- modality specific
- depends on sense used e.g. iconic, visual
sensory register capacity
unlimited
sensory register duration
limited (less than 0.5 seconds)
STM coding
acoustic
STM capacity
limited 5-9 items
STM duration
limited 18-30 seconds
LTM coding
semantic
LTM capacity
unlimited
LTM duration
potentially a lifetime
baddeley - AO1
coding in STM
AIM
to investigate how we code information in STM
baddeley - AO1
coding in STM
PROCEDURE
- showed ppts words from 4 categories
1) acoustically similar e.g. sat, cat, hat, rat
2) acoustically dissimilar e.g. tree, house, flour
3) semantically similar e.g. sleep, snooze, rest
4) semantically dissimilar e.g. cake, book, plane - asked ppts to recall lists iIMMEDIATELY AFTER
- in the correct order
baddeley - AO1
coding in STM
FINDINGS AND CONCLUSION
findings: most mistakes made in acoustically similar list
conclusion: STM codes acoustically
baddeley - AO1
coding in LTM
AIM
to investigate how we code information in LTM
baddeley - AO1
coding in LTM
PROCEDURE
- showed ppts words from 4 categories
1) acoustically similar e.g. sat, cat, hat, rat
2) acoustically dissimilar e.g. tree, house, flour
3) semantically similar e.g. sleep, snooze, rest
4) semantically dissimilar e.g. cake, book, plane - asked ppts to recall lists 20 MINUTES AFTER
- in the correct order
baddeley - AO1
coding in LTM
FINDINGS AND CONCLUSION
findings: more mistakes made on semantically similar list
conclusion: LTM codes semantically
miller - AO1
capacity of STM
AIM
to investigate capacity of STM
miller - AO1
capacity of STM
PROCEDURE
- digit span technique
- shown a string of unrelated digits
- increased by 1 every time
- had to recall in correct order
- digit span measured until no longer could recall in correct sequence
miller - AO1
capacity of STM
FINDINGS/CONCLUSION
- STM capacity limited
- 5-9 items
- increased capacity if placed into meaningful chunks
Peterson and Peterson - AO1
duration of STM
AIM
to investigate duration of STM
Peterson and Peterson - AO1
duration of STM
SAMPLE
24 undergraduate students
Peterson and Peterson - AO1
duration of STM
PROCEDURE
- ppts presented with consent trigram to learn e.g. HDF
- given 3 digit number and asked to count backwards (prevents rehearsal)
- stopped at different intervals e.g. 3,6,9,12,15,18
- asked to recall consonant trigram
Peterson and Peterson - AO1
duration of STM
FINDINGS
- when stopped at 3 seconds less only 80% correctly recalled trigram
- when stopped at 18 seconds less than 10% recalled correctly
Peterson and Peterson - AO1
duration of STM
CONCLUSION
- STM duration is limited
- 18-30 seconds
- unless rehearsed
bahrick - AO1
duration of LTM
AIM
to investigate duration of LTM
bahrick - AO1
duration of LTM
SAMPLE
394 American high school graduates aged 17-74
bahrick - AO1
duration of LTM
PROCEDURE
- placed ppts in 2 conditions
- condition 1 = recall memory of former classmates with photobook
- condition 2 = recall names of former classmates with no photobook
bahrick - AO1
duration of LTM
FINDINGS
- condition 1 = 70% recall after 48 years
- condition 2 = 30% recall after 48 years
bahrick - AO1
duration of LTM
CONCLUSION
- certain types of information can potentially last a lifetime
- especially with correct cues
weakness - AO3
lacks mundane realism
THINK FURTHER
P - research into (duration of STM)
- lacks mundane realism
E - artificial task
- (recalling consonant trigrams)
E - difficult to generalise findings (STM duration = 18-30 secs)
- to real life (duration of STM)
- research does not reflect most real life memory activities
- meaningful information
L - lowers external validity of (STM duration)
THINK FURTHER
- sometimes we do remember meaningless info
- e.g. groups of digits/letters (phone numbers/postcodes)
- has some relevance to everyday life
strength - AO3
high control over extraneous variables
P - strength (coding LTM)
- high control over extraneous variables
- lab experiment
- controlled setting e.g.
E - lists matched on task difficulty
- shown lists for same amount of time
E - cause and effect between IV (list of words) and DV (accurate recall) can be established
L - increases IV
strength - AO3
high reliability
P - strength
- high reliability (STM capacity)
E - controlled setting (lab)
E - can be repeated in same conditions (e.g. same standardised procedure, shown for same amount of time)
L - to check for consistent results (STM capacity)
strength - AO3
BAHRICK ONLY
high mundane realism
P - strength
- high mundane realism
- assessing real life memories of individuals classmates
E - real life task
- may do something similar in everyday life
- e.g. finding old friend on social media
E - easy to generalise to real life
- findings on duration on LTM
L - increases external validity
criticism - AO3
BAHRICK ONLY
low control over extraneous variables
P - criticism
- low control over extraneous variables
E - no controlled environment
- e.g. how much contact ppts had with classmates after leaving school
E - cause and effect cannot be established between IV (amount of time passed) and DV (accurate recall of classmates)
L - so firm conclusions cannot be drawn on duration of LTM
- reducing internal validity
