cognition- short term memory and working memory Flashcards
-what is short term memory
-function of short term memory
-capacity for holding a small amount of information in mind in an active, readily available state for a short period of time
-functions : holds activated info from sensory memory for further processing
Short term memory capacity
-how much information can be held in short term memory
-George Miller (1956)
-millers study , the magic number seven plus or minus two
so capacity = 7 plus or minus 2 ‘chunks’ of information
what is a ‘chunk’
groups of items that have been collected together and treated as a single unit (mathy and Feldman, 2012,p346)
how can the capacity of short term memory be increased?
by chunking (think of the example in lecture)
STM capacity varies with chunk complexity
digit span = 7.7
letter span = 6.35
word span = 5.5
trigrams = 3.2
chunks rely on ______ knowledge stored in long term memory
previous
STM duration
-how long does information last in STM
-Peterson and Peterson 1959-stm without rehearsal
peterson and peterson
experiment:
-in the trial they had stimulus presentation which was 3 letters and 3 digit number
-then there was a retention interval where the subject counts backward by threes for intervals of 3 to 18 seconds (prevents the participant from rehearsing the letters and numbers so they could test how long they were held in STM without rehearsal)
-then there was recall signal and report : where a red signal light meat they had to try and recall letters.
peterson & peterson
results
-when the retention interval was short, the percent correctly recalled was high
-as the retention interval increased, the percentage correct is decreased
-without rehearsal we can hold 3 letters in our short term memory for around 18 seconds
how is information lost from STM?
-decay : information may decay over time without rehearsal
-interference : information presented from previous trials and during the retention interval may interfere with the to-be-recalled information in STM
– could the counting backwards have actually interfered with memory- not just preventing rehearsal
stm duration
waugh and norman 1965
-they designed an experiment in which participants were presented with list of 16 digits
-after the last digiti, theres a tone that reminded the participant that this is the last digit
-they also told the participant that the last digit was a repeat of an earlier digit (called this this the probe digit)
-participant had to write down the digit that followed the earlier one (the one after the probe digit)
how did waugh and norman test the effect of interference manipulation with this experiment
-interference manipulation : decreasing the number of interference items between the last digit and the earlier digit
(large interference had lots of numbers between )
(little interference had the probe digit near the end)
how was decay manipulated in this experiment
decay manipulation :2x speed on the presentation
-1 digit per second
-4 digits per second
by varying the presenting speed you can manipulate the decay of information
results of Waugh and Norman experiment
-interference plays a larger role in short memory performance.
interference was more important than decay in terms of information lost in short term memory
STM vs working memory
compare
-different concepts with overlapping component
short term memory
-short term storage of information
-eg remember a phone number
working memory
-short term storage of information
-AND manipulation of this information
eg remember a phone number and then also be able to switch the last two digits ‘oh sorry that’s wrong the last two digits are swapped’
-your working on whats been stored in your memory
explain the working memory model
Baddeley & Hitch (1974)
central executive
(controls and used to process info in the subcomponents (eg swiitching from one task to other)
-phonological loop (inner speech , any language, sound, auditory info is stored and processed in the phonological loop
-Visuospatial Sketchpad (visual and spatial information stored in this)
-episodic buffer - (proposed in 2000 , a recent component) forms a united component of one perception (combine info from diff components and ltm to form a single united perception)
working memory model
phonological loop
-function
-function - process and store info briefly in a phonological (speech based) form
phonological loop:
what are the two components
phonological loop consists of two components
phonological store
-holds auditory information passively online (info in this store will decay rapidly if nor rehearsed)
rehearsal process
-refreshed information in the phonological store item by item
give evidence for the rehearsal process
-demonstrated by phonological similarity effect
-people show poorer recall when items are phonologically similar than when they are phonologically dissimilar
eg rehearsing phonologically similar words like man,mad,cap is harder as they’re so similar so therefore there is poorer recall
vs
related words semantically (eg big, great, large) better recall
2) evidence for rehearsal
word length effect
-the longer the word the more difficult to rehearse and therefore the memory performance is worse
-recall decreases as length of word increases (Baddeley et al., 1975)
how is the phonological loop important in learning a foreign language
-neuropsychological evidence suggests that the loop is important to language learning because patients with impairments cannot learn a new language
phonological loop important in learning a foreign language
-evidence
-patient case (patient PV) had acquired a pure phonological loop deficit as an adult, resulting in a digit span of two items.
-she had only relatively minor language comprehension problems with very long sentences but a profound inability to learn a new language
-she was tested, on learning noble words in her native language or noble words in russian
-her capacity to learn pairs of meaningful words was unimpaired, but she was not able to learn foreign language vocabulary
visuospatial sketchpad
function
-function temporary storage and manipulation of visual and spatial info
visuospatial sketchpad
-the two components (Logie 1995)
the visual cache
-store information about visual form and colour
the inner scribe
-process spatial and movement (eg mental rotation or mental folding)
visuospatial sketchpad
what was the experiment with evidence supporting visual and spatial working memory
- Klauer and Zhao (2004)
main task
-gave participants the main tasks to either memorise dot locations (spatial task) or memorise Chinese ideographs (a visual task) (so could not rehearse the Chinese figures)
(participants were not Chinese speakers)
secondary interference task
-either to make a judgement about movement direction -movement discrimination task (spatial interference)
-or a colour discrimination task (visual interference)
-if the two tasks require the same process they will interfere with each other
results of klauer and zhao experiment supporting separate visual and spatial working memory
spatial task was more interfered by the movement judgement task
for visual task, it was interfered more by the colour tasks
-this clearly supports the separation of a visual process and spatial process in visual spatial sketchpad
central executive function
-a flexible system responsible for the control and regulation of cognitive processes
-it is the most important and versatile component of working memory
-heavily involved in almost all complex cognitive activities but does not store information
episodic buffer
function
-to hold integrated information from phonological loop, visuospatial sketchpad and LTM in the form of unified representations
capacity of episodic buffer
around 4 chunks (integrated units of information; Baddeley, 2012)
Working memory model evaluation
strengths (compared to multi store model)
-WM is concerned with both active processing and transient information storage
-WM consists of independent subsystems (multi store model doesnt) wm has several like verbal , spatial,visual store
-WM model does not over emphasis the importance of the rehearsal for Short term memory retention (as its not the only thing thats important for retention)
-WM model can be applied to more real life tasks (eg learning a foreign language)
weaknesses of working memory model
-lack of knowledge on central executive function and episodic buffer
-there could be more domain specific components
-lack of knowledge on the interactions of different components
working memory in real life
-its importance for controlling external distraction
-studies shown that aeroplane noise hurts the recall of a prose passage more in low working memory individuals than in high working memory individuals (sorqvist , 2010)
-that means that high working memory individuals have a better ability to inhibit the external distracting information
working memory importance in control internal distraction (mind wandering)
-studies shown that low wm individuals engaged in more task unrelated thought than high wm individuals in a sustained attention task(a task in which your constantly remembering new information for long periods of time) (Mcvay & Kane,2012)
working memory and fluid intelligence
-WM capacity strongly correlates with fluid intelligence (non verbal reasoning ability applied to novel problems)
