1: Nature/features of memory Flashcards
What is memory?
the mental process used to encode, store and retrieve information
3 memory stores
sensory register
short term memory
long term memory
what is the sensory register
a memory store which gathers information through the senses and decides whether to further process the information to the STM
information that isn’t attended to (attention) is lost (decay)
what is short term memory
the systems which provide retention of limited amounts of material for a limited time period.
information is sent to the STM if it has received attention at the sensory register
the STM is a temporary memory store and if information is not rehearsed at this stage it is lost (decay)
what is long term memory
a type of memory storage that involves storing info over long periods of time
information can be transferred from the STM to the LTM by rehearsal
the LTM is a potentially unlimited memory store and information cannot be lost, only forgotten due to interference or retrieval failure
capacity
the maximum volume of info that can be held in the store at any one time
duration
the amount of time that information can be held in the memory store
coding
the way that information is processed by the store
the format or ‘type’ of information held by the store
capacity of the SR
include study
large capacity
Sperling (1960): pps shown letter chart for 0.5s: average recalled 3 letters. when indicated top, middle or bottom row: could recall 3 letters from any row.
- suggests the SR has a large capacity but limited duration as pps had no problem w holding memory of entire image, but this memory fades in time taken to recall the items
duration of SR
include study
very brief duration: approx 0.5 seconds
Sperling (1960): pps shown letter chart for 0.5s: average recalled 3 letters. when indicated top, middle or bottom row: could recall 3 letters from any row.
- suggests the SR has a large capacity but limited duration as pps had no problem w holding memory of entire image, but this memory fades in time taken to recall the items
coding in the SR
constantly receiving modality-specific information (sense-specific)
most of this recieve a no attention
capacity of STM
include 2 studies
limited to 7 +/- 2 items
Miller (1956): ‘digit span technique’ - pps read series of digits getting progressively longer/ asked to immediately recall. pps on average recall 7 +/- 2 items
- suggests STM has limited capacity of 5-9 items bc when new info comes into STM it pushes out the old info (displacement)
- capacity of STM can be increased by chunking: a process where items are grouped into larger chunks/units
Jacobs (1887): ‘digit span technique’
- suggests that pps more likely to successfully recall more digits than numbers (10 possible digits, 26 possible letters)
- suggests that capacity of STM increases with age (may be due to memory strategies)
duration of STM
include study
limited to approx 18-30 seconds
Peterson & Peterson (1959): pps listened to consonant trigram, had to count back in 3s from an random 3 digit number (to prevent rehearsal). asked to recall trigram after 3,6,9,12,15,18 seconds. 90% success after 3s, 2% success after 18s
- suggests capacity of STM is limited to approx 18-30s before the info is lost by decay.
- this duration can be extended by maintenance rehearsal: repeating the info continuously out loud or in head
coding in the STM
include study
mainly acoustic (sound)
Baddeley (1966): pps given two word lists, one w acoustically similar/one w acoustically different words. asked to immediately recall, made more errors in acoustically similar
- concluded this was because there was confusion based on how words sounded, suggesting the STM codes acoustically
- explains why maintenance rehearsal out loud can help to keep info in the STM
capacity of LTM
include study
unlimited
Anokhin (1973): estimated possible number of neuronal connections in brain is “1 followed by 10.5 million km of noughts”
- concluded no human exists that can use full potential of brain, suggesting unlimited capacity
- suggested that although we forget info, this is due to interference or retrieval failure, not that it’s no longer stored
duration of LTM
include study
unlimited: 30s up to a lifetime
Bahrick et al (1975):
1) free recall test: pps aged 17-74 asked to recall names of classmates.
- 60% success after 15yrs, 30% success after 48yrs
2) recognition test: pps given 50 photos, asked to recognise classmates names
- 90% successful after 15yrs, 70% successful after 48yrs
- suggests duration is unlimited (only limited by length of human life) we don’t need to rehearse info to store it in LTM
- if a memory cannot be freely recalled it doenst mean it’s no longer stored, may be forgotten due to retrieval failure and need assistance to be remembered (recognition)
coding in LTM
include study
mainly semantic (meaning)
Baddeley (1966): pps given two word lists, one w semantically similar/one w semantically different words. asked to immediately recall, made more errors in semantically similar
- concluded this was because there was confusion based on meaning of words, suggesting the LTM codes semantically
- in order to retain info to the LTM, we need to understand it and process it’s meaning (elaborative rehearsal) otherwise it will be lost (decay)
evaluation: strengths of research into the nature of memory
P: lab experiment: hight control over variables
E: controlled setting - control EVs
E: eg Miller can standardise time, noise, materials (digit lists) instructions
L: high internal validity (measuring intended to measure)
P: lab experiment: easy to replicate
E: controlled setting: conditions can be repeated for replications of the study
E: Baddeley: can use same word lists
L: findings can be easily checked for reliability
Evaluation: limitations of research into the nature of memory
P: materials used are often meaningless
E: don’t reflect the info we use STM/LTM for in real life
E: Miller: remembering digit lists doesn’t reflect real life memory activities where info is more meaningful/varied
L: not representative/ cant be generalised: low ecological validity
P: lab experiment: high demand characteristics
E: pps may be aware that they are being studied and act unnaturally
E: be more self conscious which may affect memory recall, or guess aim of study and give results they think the researcher is expecting
L: not measuring true behaviour (low internal validity)
