functia executiva Flashcards
what is the neuropsychological evidence against the modal model
Shallice and Warrington
KF who suffered left-hemispheric damage was tested on five verbal short-term tests
he had impaired verbal STM but intact LTM
why does this evidence contradict the modal model
model modal would predict that any problems in STM would result in difficulties in transferring information to LTM
what new model did Baddeley and hitch propose
they proposed the Working memory model
what does the working memory model consist of
Central executive (CE)
Articulatory loop (AL) - a speech based system used in verbal span tasks
Visuo-spatial sketchpad (VSSP) - a visually-based system
what is the visuo-spatial sketchpad
a memory buffer and temporary storage which manages and stores spatial and visual information by manipulating visual images and forming mental maps
used for navigation
what is the executive function responsible for
responsible for monitoring and coordinating the opration of the visuo-spatial sketch pad and phonological loop
- what is evidence for the articulatory loop
PHONOLOGICAL SIMILAIRITY EFFECT
recall of words is impaired if they are phonologically similar e.g. mop, top, sop, cop
this is bc the articulatory loop uses a phonological (sound-based) code
if words consist of a limited number of phonemes, likelihood of interference is greater
what experiment was conducted on the word length effect
ppts recalled as many words as they could read out in 2 seconds
the no of visually presented words that could be recalled was assessed
articulatory suppression eliminated the word-length effect
articulatory supression is the process of inhibiting memory performance by speaking while being presented with an item to remember
articulatory suppression eliminated the world-length effect by inhibiting and blocking articulatory rehearsal, which is a key comononent in the phonological loop and is associated with the world-length effect
what is another evidence for the world length effect
memory span and articualtion rate are highly correlated in all ages
our span increases during childhood as we become able to articualte more rapidly
articulation allows memory trace to be continually played back via the loop, which means that the more information that can be packed into the loop (by being able to articulate more quickly), the longer will be the memory span
- what is evidence for the articulatory loop
UNATTENDED SPEECH EFFECT
Colle and Welsh
ppts who listened to a German prose during recall had significantly imapired rrecall of visually presented numbers compared to those ppts who didnt hear the german prose
this occurs bc articulatory control process converts visual material into an articulatory phonoligcal (sound-based) code, which means that the irrelevant speech could interfere with the articualtory rehearsal process
is the articulatory loop for learning how to read?
children with normal intelligence but specific reading problems were found to have impaired memory spans and also bad on tasks requiring phonological awareness e.g. rhyming judgements
- Morais et al found a reciprocal relaiotnship between reading, memory span and phonolgical awareness - increasing one increases the other, even in adults - however which comes first is unclear
is the function of the articulatory loop language comprehension?
articulatory loop couldnt have developed for reading as reading is recent in evolution
AL could be for language comprehension
e.g. patients with poor STM (e.g. digit span of 1 or 2 items) are ok with comprehennding simple sentences but as gramattical complexity, sentence length increases, they have problems
Moreover, the storing of information in the phonological store of the phonological loop is dependent on the time it takes to rehearse those items in the articulatory rehearsal system, which is why longer and more complex sentences which require greater processing time may not get efficiently or effectively stored, thus impairing language comprehension
is the articulatory loop for acquiring vocabulary?
children with delayed language skills are found to have particular difficulties in repetition of non-words
non-words are important during acquisition of a vocabulary
in another study, 100 preschool children who hadn’t learned to read were tested at yearly intervals on non-word reprition and other measures of reading
clear correlation between non-word repetition and later vocabulary acquisition
implies that AL is involved in non-word repetition and acquiring vocabulary
what is the evidence for viso-spatial sktech pad
ppts imagine a visual matrix, and learn sequences of sentences of 2 types
sentences that are spatial in nature - these are visuable e.g. in the next square to the right, put a 2
sentences that are non-spatial - non-visuable e.g. in the next square to the strong put a 2
ppts remembered 8 spatial vs 6 non-spatial sentences
spatial encoding must be occuring to increase the memory span in that condition
so mental image of the map was stores in VSTM
- what is evidence for visuo spatial sketchpad
the case of LE, a 55 year old well educated female sculptor who suffered autoimmune disorder, which stipulated imapired visual short term memory together with image generation problemsn, which dramatically affecetd her sculting styel
she scored within the normal range on all the conventional tests of visuo spatial immediate memroy like WAIS, digit span test, and percetile tests
however, on test of immediate visual pattern memory, LE’S performance was severely compromised
on visual STM recognition, she scored 16/24 whilst the normal range is 20-24
what is evidence for central executive function
Jansari, Cole, McCarthy
patient AS, 24 yo man who through closed hear injury, had incurred damage to the orbitofrontal cortex in the frontal lobes
complained of problems in STM but none in LTM
problem occured most often when stressted and many people taking at once
he found it difficult to take notes in lectures at the same time as listening to the lecturer
clinical assessments using conventionally inteliigence tests for digit spans, spatial span and processing, verbal fluency, reasoning/conceptual shifting all appeared normal in AS, so both auditory loop and viso-spatial sketchpad were well preserved and intact following orbitofrontal damage
tests on immediate free recall revealed that AS performed differently from other patients with poor STM and exhibited normal recency effect, which indicated effortless retreival from STM
however, AS exhibited profoundly imapired asymptote and primacy effect, suggesting profound impairments in LTM mermoy consolidation
what is the n-back test
a test of ability to shift attention between storage and processing functions over short time intervals
ppts saw individual letters on a computer screen for 2sec each and at random points had to report the item n-back
2 conditions:
- location - positioning of consecutive letters of the alphabet changed on the screen and task was to point to where the n back position was
-identity - non-consecutive consonants presented centrally on the screen and task was to state the item that was n-back
AS performed worse at this task
- what is evidence for central executive
pursuit moto (complex task using VSSP) and digit span (using AL) tasks were adjusted so that individual performance was identical in patients with senile demential of the alzheimers type, normal elderlies and young control subjects
this demonstrated that their AL and VSSP was well preserved and intact within the SDAT patients
the tasks were then combined and thus requiring activation and recruitment of the CE control which co-ordinate the 2 slave systems by distributing attentional resources to mediate information processing effectively in between the 2 systems
SDAT patients were significantly imapired relative to control on this combined task, thus suggesting that impairment must be in the CE since they were able to perform the tasks individually
what is the central executive
number of diverse roles -
coordinting the activity of the subsidary systems - the AL na d the vSSP
- corodinating retreival strategies from long ter memory
- selective attention which allows the cognitive system to focus on the most relevant information
what is norman and shallice supervisory attentional system model
controlled behaviour arises through the selection and implementation of schemas, which are sets of actions or cognitions that have become associated with each other thorugh repeated exposure and oractice
what are the 2 ways that schemas can be activated
contention scheduling
supervisory attentional system
what is contention scheduling
once a particular schema has been driggered, contention scheduling ensures that the activation of other schemas is inhibted (e.g. looking in the mirror while driving does not lead to the person adjusting their hair)
contention scheduling is fast, automatic
that is the supervisory attentional system
brought into play to cope with non-routine, difficult or dangerous situations, initiate willed behaviour and make decisions
SAS monitors novel situations that cannot be solved by previously learnt schemata
what is clinical evidence for the SAS
Evidence comes from neuropsychology - patients with frontal lobe lesions - the dysexectuive syndrome
