Coding, Capacity and Duration Flashcards
what are the 2 different types of memory?
short term memory
long term memory
what is short term memory
memory for immediate events - things that only just happened
what is long term memory
memory for things that happened in the past
what is the definition of coding
how info is changed/ converting info from one memory store to another
definition of capacity
how much info can be held in memory at any time
definition of duration
how long info can be held in memory
what does acoustically mean
associated with sound
what is encoding
how info enters memory system from sensory input
what are the 3 types of encoding
visual (as an image)
acoustic (as a sound)
semantic (through meaning)
how is info coded visually
as an image
how is info coded acoustically
as a sound
how is info coded semantically
through meaning
how is STM coded?
info coded acoustically
how is LTM coded
info coded semantically
what is the capacity of STM
5-9 items
what is the capacity of LTM
unlimited capacity
what is the duration of STM
18-30 seconds
what is the duration of LTM
unlimited duration
what does ‘digit span’ mean?
no. of items individuals can recall correctly
what is chunking
grouping sets of digits/letters until chunks
research on coding
- Baddeley (1966) gave different words to 4 groups: accoustically similar (sound similar), accousitcally disimilar, semantically similar (similar meanings) and semantically disimilar.
- when recalling words immediately (STM) they did worse with acoustically similar words
- when recalling words after 20 mins (LTM) they did worse with semantically similar words.
—- suggests info is coded semantically in LTM
evaluation for Baddeley’s research on CODING
artificial stimuli - cannot be generalised, as the words were random and had no meaning to the participant
research on capacity - digit span - Jacobs
digit span
- Jacobs (1987) - researcher gave certain amount of words and participants have to recall in correct order . increase amount of words until they can no longer be recalled.
- mean digit span for digits - 9.3
- mean digit span for letters - 7.3
research on capacity - span of memory and chunking - Miller
span of memory and chunking - digit span test
- Miller (1956) noted things in sevens (days of the week) - suggests capacity of STM if 7
- miller noted people can recall 5 words and 5 letters by chunking - grouping sets of digits or letter.
- found average capacity was 7+/- 2 chunks of info
evaluation for Jacobs research on capacity
lacking validity
- study was conducted long time ago - meaning variables may not have been controlled
- however, other research had confirmed its validity.
evaluation of Miller’s research on capacity
not so many chunks
- miller may have overestimated the capacity of STM
- Cowan (2001) reviewed other research and stated capacity of STM was 4
research on duration - duration of STM
duration of STM
- Peterson and Peterson (1959) tested 24 students. they had to count down from a 3 digit no. after being told a consonant syllable (to prevent mental rehearsal). they were told to stop after either 3,6,9,12,15 or 18 seconds
- suggests STM may be very short unless we mentally rehearse it
research on duration - LTM
duration of LTM
- Bahrick (1975) studied 392 participants aged 17-74. recall was done by photo recognition of 50 photos from high school yearbook, or free recall of names of graduating class
- photo recognition - 15 years after graduation - 90% accurate , 48 years - 70%
- free recall - 15 years after graduation - 60% - 48 years - 30%
— shows LTM can last very long
evaluation of Peterson and Petersons study on duration - STM
meaningless stimuli in STM study
- study used artificial material - does not reflect real-life memory activities
- not completely invalid - e.g phone numbers
evaluation of Bahricks study on duration - LTM
high external validity
- Bahrick et al used real life memories
- confounding variables not controlled - participants may have looked at yearbook over years
evaluation - critics of Peterson and Peterson
in study participants counted down during the retention interval, meaning info in STM may have been displaced
