b1 - features of memory stores Flashcards
what is memory?
memory is an organisms ability to store,retain and recall information and experiences
what are the three main components of memory?
sensory register
short term memory
long term memory
what is coding in memory?
the way information is processed or stored in memory
what is duration in memory?
the length of time the information is held in the memory store
what is capacity in memory?
the amount of information that can be stored
how does information enter the sensory register?
via our senses
what is the capacity of the sensory register?
unknown / unlimited
what is the duration of the sensory register?
limited
less than a second / 250 milliseconds
how is information coded in the sensory register?
modality specific (depends on the sense) e.g. visual = iconic, acoustically = echoic, touch = hepatic
what must happen to information before it’s passed from the sensory register to the short term memory?
it must be attended to
define short term memory
is your memory for immediate events
memory disappears unless rehearsed
what is the capacity of the STM?
limited
7+/-2 pieces of information
what is the duration of the STM?
18-30 seconds
how is information in the STM coded?
acoustically
name a study of coding in the STM and LTM
Baddeley (1966)
explain Baddeley study on coding in memory
procedure:
he gave different lists of words to 4 groups of ppts to remember:
G1: acoustically similar (cat,cab,can)
G2: acoustically dissimilar (pit, few, cow)
G3: semantically similar (great, large, big)
G4:semantically dissimilar (good, hot, pig)
findings:
ppts asked to recall words in correct order immediately (STM) = worse with acoustically similar words - STM acoustically coded
ppts recalled words 20 mins later (LTM) = worse with semantically similar words - LTM semantically coded
two positives of Badddeley’s study on coding in memory
the study identifies clear differences between the two memory stores.
replicable
one negative of Baddeley’s study on coding in memory
artificial stimuli - no personal meaning - findings have limited application
name two studies on capacity in STM
Jacobs (1887)
Miller (1956)
explain Jacobs study on capacity in STM
procedure: used a digit span test, ppts had to repeat back a string of numbers/ letters read out by the experimenter, the number of digits/ letters was gradually increased until ppts could no longer recall the sequence in the correct order. findings: the mean span for digests was 9.3 items the mean span for letters was 7.3 items
one limitation of Jacobs study of capacity in STM
study is very old, early psychological studies lacked control of extraneous variables - confounding variables
one strength of Jacobs study on capacity in STM
has been replicated and findings have been confirmed by other studies
explain Millers study on capacity in STM
he observed in everyday life, things come in sevens (seven days of week, seven deadly sins etc)
he thought the capacity of STM was about 7 items, plus or minus 2
he also notes people can recall 5 words as easily as they can recall 5 letters = chunking (grouping sets of digits or letters into units or chunks)
one limitation of Millers study on capacity in STM
his research overestimated the capacity
Cowan (2001) found the capacity of the STM is only 4 +/-1 chunks
so millers 7 (-2) = 5 is more appropriate
name a study of duration in STM
Peterson and Peterson (1959)
explain Peterson and Peterson’s study on duration in STM
procedure:
tested 24 students in 8 trials each. on each trial the student was given a constant syllable (e.g. YCG) to remember and given a 3-digit number.
the student counted backward from this number until told to stop (this was to prevent mental rehearsal).
on rachel trial they were told to stop after varying periods of time (3,6,9,12,15 or 18 seconds)
findings:
3 seconds = 80% recall
18 seconds = 3% recall
suggesting STM duration is about 18 seconds (unless we rehearse)
one limitation of Peterson and Peterson’s study of duration in STM
the stimulus material was artificial - doesn’t reflect everyday life - lacks external validity
one strength of Peterson and Peterson’s study of duration in STM
highly controlled- replicable
define long term memory
is your memory for events that have happened in the past
what is the capacity for LTM?
unlimited
what is the duration of LTM?
up to a lifetime
how is information coded in LTM?
semantically
name a study of duration in LTM
Bahrick et al. (1975)
explain Bahrick et al.’s study of duration in LTM
procedure:
studied 392 american ppts aged 17-74.
recall was tested with the individuals high school year books.
test 1: photo-recognition - 50 photos, some photos from their year book, and asked to name them.
test 2: free-recall - recalled names of their graduate class (no pictures)
findings:
photo recognition: ppts with in 15 years of graduation = 90% correct vs ppts after 48 years = 70% correct
free recall: 15 years = 60% vs 48 years = 30%
shows LTM can last up to a lifetime
one strength of Bahrick et al.’s study of duration in LTM
height external validity- use of meaningful memories
one limitation of Bahrick et al.’s study of duration in LTM
confounding variables - can’t be sure the ppts hadn’t looked at their yearbook and rehearsed over the years
