coding, capacity and duration Flashcards
what is coding
coding is how info is changed or stored in memory - differs depending on the memory store
what is capacity
capacity is how much info can be held in memory at any one time
what is duration
duration is how long info can be held in memory
how many types of memory are there
2
what are the 2 types of memory
short term memory
long term memory
define short term memory
short term memory is used for immediate events and things that have only just happened
define long term memory
long term memory is used for things that happened in the past e.g. holiday when i was seven
what are the different ways memory can be coded
- visually (picture)
- acoustically (sound)
- semantically (meaning)
how is the short term memory coded
information is mainly coded acoustically (through sound)
what is the capacity of short term memory
5-9 items
how long can info be kept within short term memory
18-30 seconds
how is long term memory coded
information is mainly coded semantically (through meaning)
what is the capacity of long term memory
unlimited
how long can information stay within long term memory
unlimited duration
who did research into capacity (2 individuals)
- jacobs
- miller
what was Jacobs research into capacity of memory
- participants presented with 4 digits which must recall in correct order out loud
- repeat task with increasing no. of digits until mistake
- average span - 9.3 digits
- mean span - 7.3 digits
what does digit span mean
digit span is the number of items an individual can recall correctly without making mistakes
what are the two topics Miller undertook capacity research on
- magic numbers
- chunking
what is chunking
chunking is grouping sets of digits/letters into units or chunks in order to aid recall
what was outcome of Millers research into chunking
he spotted people can recall 5 words as well as 5 letters
what did Miller suggest about magic numbers relating to capacity of STM
Miller suggested that the capacity of STM is about 7 items +/- 2
evaluation point for millers research into capacity
- miller stated that STM had capacity of 7 items +/- 2
- alternative researchers cowen and vogel et al suggest capacity of STM is actually about 4 items suggesting lower end of Miller’s range (5) is more appropriate
evaluation point - research for capacity and chunking
SIZE OF CHUNK
- simon found people have shorter memory span for larger chunks (8 word phrases) than smaller chunks
- suggests people arent able to remember large chunks compared to smaller ones which may be seen as easier to remember
evaluation point relating to digit span with further research- capacity
INDIVIDUAL DIFFERENCES
Jacobs also found digit span increased with age
- suggests may be increase in brain capacity in brain capacity and people may develop strategies (chunking) to improve their digit span
who provided research into coding
Baddeley
outline Baddeley’s study for coding
- gave different list of words to 4 groups (acoustically similar, acoustically dissimilar, semantically similar, semantically dissimilar)
- participants where shown original words and asked to recall in correct order - when doing it immediately (STM recall) after hearing they tended to do worse acoustically
- when participants were asked to recall after 20 min interval (LTM recall) they did worse with semantically similar words
what does acoustically similar mean
words sound similar
e.g. cat, cab, can
what does acoustically dissimilar mean
words sounding different
e.g. pit, few, cow
what does semantically similar mean
words with similar meaning
e.g. great large big
what does semantically dissimilar mean
words that all have different meaning
e.g. good, huge, hot
evaluation point relating to coding and baddeleys research
- using artificial and meaningless stimuli - weakness because theory does not reflect how memory works in everyday life so lacks external validity
who did research in duration of long term memory
Bahrick et al
what study did bahrick et al undertake to look at duration of LTM
- tested participants aged 17-74 using high school yearbooks
- recall tested through (1) photo recognition test of 50 photos and (2) free recall test where participants recalled those who where in their graduation class
results for bahrick et als yearbook photo recognition study
after 15 years 60% were able to free recall and 90% correctly recognised from yearbook.
after 48 years 30% were able to recall and 70% correctly recognised from yearbook
summary of bahrick et als study relating to duration of LTM
he got participants to recall or recognise classmates and found that as years increased since graduation memory decreased
who did research relating to duration of STM
peterson and peterson
what was peterson and petersons research about relating to duration of STM
- asked particpants to recall trigram (series of 3 letters)
- participants had to count back from 3 digit number until told to stop (time stopped varied - 3,6,9,12,18 seconds)
- found that the longer participants had to count for the poorer their recall was
what is retention interval
the period of time between exposure and being tested
evaluation points of duration of STM and LTM
- bahrick et al’s study has high external validity because there were low levels of control and may have been variables affecting recall such as rehearsal (looking at yearbook before) or popularity
