Working memory and its neural mechanisms (Chris) Flashcards
What components make up Baddelely and Hitch (1974)’s working memory model?
Central executive
Phonological Loop
Visio-spatial sketchpad
What does the phonological loop do?
Processes digit span information
What’s the role of the central executive?
More high-level cognitive processes e.g., manipulation of stored information, coordination of resources and attentional control
What is Spearman’s ‘g’ factor and working memory?
Measures general intelligence based on correlations between sensory ability (distinguishing between tones) and academic ability.
How was Spearman’s ‘g’ factor later adapted?
Explained how general intelligence influenced by two underlying factors:
Fluid intelligence - reasoning + problem solving (Gf)
Crystallised knowledge - general knowledge (Gc)
How did Kyllonen & Christal (1990) support Spearman’s later model?
Gave subjects tests of different processes e.g., general knowledge and working memory + found very high correlations between fluid intelligence and working memory
What correlations were found in relation to Spearman’s ‘g’ factor?
Verbal reasoning ability and WM tasks had the highest correlation of 0.76
What did Kane & Engle (2002) aim to investigate?
Working memory and fluid intelligence
What was Kane & Engle’s (2002) procedure?
Participants had to solve each math problem + say the word aloud and then recall all 3 words at the end.
Then gave Ps a simple span task - say each word aloud then recall all 3 at the end to distinguish between short term storage component and WM
Then gave Ps Raven’s matrices to test reasoning ability (fluid intelligence)
What did Kane and Engle (2002) conclude?
Identified 3 underlying factors: working memory factor, short-term factor and processing speed factor
Found WM had a very high correlation with Gf
Also found that fluid or general intelligence involves ‘executive attention’ component of WM - attention plays a key role to focus on irrelevant aspects of the task
What did Duncan et al (2012) conclude using complex WM span tasks?
The WM correlation was higher for the rule working memory task, meaning that when you make the tasks difficult in terms of complexity of rule set, this taps into fluid intelligence.
Positive correlation between task performance at IQ.
How does WM work at a manageable level?
Must subdivide goals to break down complex problems into manageable chunks
What was Duncan et al’s (2017) methodology?
Asked Ps to draw what they thought should go into a space/box together and in a separate condition.
What were Duncan et al’s (2017) findings?
Found people performed well on the task in the separated condition, even those with lower IQ.
However, in the combined condition, results found a correlation between poor task performance and low IQ - however, this correlation disappears when the task is broken down to become more manageable.
What is the ‘standard model’ of the role of the prefrontal cortex (PFC) in working memory?
Temporary representations of memory are stored in the PFC
What did Fuster (1974) find in relation to neurons in the PFC.
Neurons in the PFC fire during working memory - monkeys see food appear and then disappear, being instructed to find the food - see elevated activity during the delay period of a working memory task
How is the PFC thought to maintain this temporary information?
Using a temporary storage buffer
What is an oculomotor delayed response task and what has it told us about the role of the PFC?
Cued stimulus that after a delay period, monkeys must remember the cue. Found that in monkey’s PFC, during delay period, elevated activation in neuron firing and direction specific (contains information about the stimulus)
What did Petrides & Milner (1982) find in patients with temporal and frontal cortex lesions?
Frontal cortex participants are disproportionally impaired in the task - suggesting a role in working short-term memory
How did Wilson et al (1993) show evidence for the dorsal PFC?
Sent monkeys a cue they must remember (spatial task) and a patterned version - learn to associate patterns with eye movement direction responses.
Found during the delay period, elevated activation in pattern WM task in the ventral neuron but not in the spatial WM task.
What did Courtney et al (1996) find for evidence of the PFC using PET scans?
Tried to dissociate between object and spatial WM: either remember 3 faces + their identify (object), and then remember the location of faces (spatial).
Found activation in the ventral PFC elevated in object task and vice versa.
How did Rao et al (1997) object to the ‘standard model’ of the PFC?
Found over half the neurons in a monkey object recognition task showed both object and location selectivity instead of finding clear object and spatial selectivity. Appears that the PFC involved in much more flexible coding.
What is a possible confound against the ‘standard model’?
Strategies to help performance on the spatial task e.g., strategic chunking of locations and draw a pattern between them, it’s easier to remember
What is the alternative explanation for the PFC rather than the ‘standard’ model?
That the PFC is organised according to type of processing rather than type of information stored here.
What was D’Esposito’s (1999) methodology to investigate against the ‘standard model’ of the PFC?
Had participants alphabetise a set of digits in their mind, followed by a delay period, with a probe then given, had to decide if the probe is part of the set and what order it would be.
What did D’Esposito et conclude about the PFC?
Found activation in dorsal + ventral PFC increased during this manipulation task.
Evidence for dorsal and ventral PFC involved in manipulation of information during WM - problem solving and reasoning ability, suggesting that the PFC isn’t organised according to type of stimulus (standard model)
What is multivoxel pattern analysis of fMRI data?
Uses machine learning techniques to teach an algorithm about a pattern of neural activation associated with a particular stimulus.
Takes advantage of fine-grained patterns of activation in the brain.
How does the algorithm of multivoxel pattern analysis work?
De-code what a subject is looking at by viewing patterns of brain activity
How did Linden et al (2012) investigate multivoxel analysis?
Had subjects see 3 flowers, delay period and then 1 flower shown .
4 Categories of objects shown (face, bodies, flowers and scenes) and then can see what category Ps working memory was focusing on.
How did Linden et al’s (2012) multi-voxel analysis demonstrate WM?
Found WM evident through the visual cortex. Concluded that the same regions that enable us to process objects with our eyes is also involved in storing temporary representations of those objects in WM.
What was Riggal & Postle (2012)’s experiment using multivoxel pattern analysis?
Presented Ps with a sample with a delay period and a cue - Ps had to remember either the speed/direction of sample dots + say whether the probe was the same as the original sample.
What were Riggall and Postle’s findings (2012)
Success from occipital and temporal cortex for decoding item specific information.
Can de-code where Ps were asked to attend to looking at activation in the frontal cortex during the delay period. However, this is not stimulus specific.
What was Postle’s (2006) alternative view to the standard model?
WM is attention to the internal stimuli that we’re holding - the PFC controls/allocates this attention.
How did Higo et al (2011) support Postle’s (2006) alternative view to the standard model?
Found that activation in the PFC greater for a selective attention than non-selective - found PFC performs a much more attentional role, establishing causation.
