7-WorkingMemory Flashcards
What is a task set?;
Preparation to perform one task rather than another; involves selecting, linking, enabling “modules” for task components (e.g., perception, response selection)
When do switch costs arise?
In establishing the appropriate task set & disengaging an inappropriate set
What does a typical switching task procedure involve?;
How do you avoid confounding practice & fatigue?
Usually simple responses to digits & letters (e.g. AABB, etc, where A is one task & B is another);
These are matched over switch trials and same-task trials
When the task changes, even though the task changes are regular and thus predictable, what is usually observed?
A severe switch cost of up to several hundred ms
Jersild (1927) found there were small switch costs if both stimuli and responses were different (e.g., number task alternating with word task). When were major costs incurred?;
Do participants occasionally forget what task is next?
When participants change the task and thus the response selection rule for a common stimulus configuration (attaching 2 response demands to the same set of stimuli becomes tricky);
No. No evidence of occasional slow trials; instead a general slowing over the RT distribution
There is a large literature showing that repeated stimuli are processed more easily (through pre-activation of their memory representations). When is this not the case?
When these repetition effects are controlled (e.g. same stimulus on every trial but cued to do different things with them), resulting in switch costs
In Rogers & Monsell’s (1995) AABB paradigm, digit-letter pairs appeared in one of 4 boxes & participants pressed right or left buttons for odd or even digits; & right or left for consonants or vowels in the letter task. How did they perform in switch tasks compared to non-switch tasks?
There was a large switch cost (even though task switches were predictable); a large improvement on day 2, especially for switch trials; similar performance for letter and digit tasks (similar difficulty)
What occurs with practice of separate tasks & switching tasks?
Costs are reduced but not eliminated
In relation to task difficulty, what incurs the greater cost?;
What does this result suggest about the roles of relevant task engagement vs. irrelevant task disengagement in switch costs?
Switching TO the easier / dominant task (e.g., from colour naming to word naming in Stroop task);
The prior difficult task requires effort & concentration so it’s hard to disengage (counter-intuitive)
Rogers & Monsell (1995) conducted a study with an emphasis on Task Set Re-configuration (TSR) prior to the switched task (had to change task set to meet demands of the next task). What was found?
Can maintain 2 task sets for different tasks & stimuli. But with different responses for the same stimuli, need to change task set when task changes (applying to a common set is harder to maintain)
In a task-cuing paradigm by Sudevan & Taylor (1987), participants made different judgements about digits. They were cued before the trial as to which task to perform & the cue to digit interval was manipulated (400 to 4000 ms). What was found?;
What factors confounded with these results?
Switch cost decreased as the interval increased to 2-3 sec (more time given, the lower the switch cost);
Preparation time with delay from the previous trial
Meiran (1996) had participants give the position of a disk (up, down vs. left, right); they were given a pre-trial cue. They maniplated cue-to-next-stimulus interval and last-response-to-cue interval. What was found?;
What does this suggest?
A short cue-to-stimulus interval led to a large switch cost even if there was a long delay from the last trial;
That it’s an active preparation effect, not just decay of effects of prior trial (involves both disengaging the past task and engaging the coming task)
Can adequate preparation remove the switch cost?
No, there is always a residual cost (so task preparation is not the whole story)
What kind of effects are residual costs?
Exogenous effects - “stimulus driven” (no matter how prepared you are you can’t do any decision-making for the next trial until the stimulus has been presented and identified)
Meiran found that response selection on switch trials is subject to interference from the prior trial, & that deciding on the response for the current stimulus may be affected by what?
The response associated with the stimulus for the alternative task (e.g. pressing L in one trial then R in the next)
In Roger & Monsell’s Task congruity trial with letter-digit stimuli, what was the effect between congruent & incongruent trials?;
What does this reflect?
Incongruent (R for letter, L for vowel) produced a slower reaction time than congruent (R for both);
Participants’ learning of responses for certain stimuli
In what ways do theories of the switch cost differ?
The role of active preparation (endogenous factor); the role of interference effect from prior task & task set that dissipate passively (with the passage of time); whether exogenous factors play a role
Describe the Disengagement theory by Alport et al.
Proactive interference occurs from “task set inertia” (TSI) – we hang on to the prior task; this decays after several minutes; but impairs adoption of the alternative task set
Explain the Endogenous component described by Rogers & Monsell;
The residual cost that cannot be removed by adequate preparation is due to what?
Preparation by participant requires time; switch cost is reduced as preparation time increases.
An exogenous component of the task set that must be triggered by the arrival of a suitable stimulus
Describe the Endogenous Only theory by de Jong
The residual cost arises because participants do not prepare adequately on every trial
As proposed by Nieuwenhuis & Monsell, 2002, what can we conclude about switch costs?
That even when motivation, fatigue & practice addressed, and RTs decrease, a residual switch cost remains, so it’s necessary to consider both endogenous & exogenous control
What is Kahneman’s capacity theory in regards to automaticity?;
According to this theory, what does substantial practice lead to?
Over-learned tasks become automatic & consume few resources;
Improves performance, reduces task effort; facilitates re-structuring and co-ordination of concurrent tasks
Shiffrin & Schneider gave participants a memory set for targets to be searched for in the upcoming trial, they then had to press a key as soon as they saw a target, or another key for no target. What were the key IVs for automaticity?
Size of memory set (2 vs. 4 letters); categorical/consistent mapping (targets came from one set of letters, & distractors from another set); mixed/varied mapping (targets and distractors came from one item set)
In Shiffrin & Schneider’s study, what was found in the categorical condition?;
What about the mixed condition?
Accuracy cost for larger memory set (4 vs. 2) but after practice, there’s no effect of memory set size - evidence of automaticity;
It’s impossible to use a simple response rule & become automatic; there’s always a cost of having a larger memory set (even after nearly 10,000 trials)
How do automatic processes occur?;
What did Shiffrin & Schneider find that shows a downside to these last two characteristics?
Quickly, without awareness, conscious deliberation, or expenditure of resources; they’re rigid & habitual;
Participants had difficulty in the categorical condition when the assignment of items was reversed (difficult to unlearn responses)
Name two other examples of how automaticity might be a problem
Automatically reading a word that is looked at (Stroop task); & spread of activation in semantic networks in memory, (association of concepts, e.g salt activates pepper)
According to Logan, what’s automaticity based on?;
Knowledge acquisition (not all-or-none); we have separate memory traces for each encounter with a stimulus
What does practice lead to, according to Logan?;
So according to this theory, what is automaticity?
Storage of information about the stimulus, how to respond to it, & rapid retrieval of it (in the absence of practice, thought and application of rules is required);
Memory retrieval – a single step direct-access retrieval of a past solution
What are some problems with the traditional criteria for automaticity?
Capacity & interference (even well-practised tasks will display interference if stimuli & responses are similar (e.g. dichotic listening); mode of control (automatic processes are obligatory only when they relate to the intended action)
In the Stroop task, if the word & colour have a clear spatial separation (e.g. in the periphery), what can be avoided?
Interference
Describe some links between awareness & automaticity
Can have a lack of awareness in intentional tasks (e.g. aware of cue but not retrieval process); awareness of highly routine tasks (e.g. routine turn at an intersection); level of control is critical (automatic performance = when skill + input information specify task completely; other attentional mechanisms bring interference and awareness)
If you mistakenly take a routine turn at an intersection, does this mean the action is unconscious?
No, rather, the link with the intention is lost (automatic pilot)
Define Working Memory (WM)
It’s the domain of conscious thought; involved in making decisions and initiating actions based on plans & in response to environmental input; also involved in directing attention
What components make up Baddeley’s WM model?
Central executive coordinates activity of the “slave” systems that store information: the phonological loop; visuo-spatial sketchpad; episodic buffer
What does the Episodic Buffer do?
Links information across visual, verbal, and spatial domains
Who is the Homunculus?;
Why is the homunculus a problem?
The one who “sees” & “interprets” the image mapped from the retina to the brain; decides which cognitive task should get priority in order to meet goals; inhibits processes that are irrelevant to the current goal;
Doesn’t make sense – who controls the controller?
What is the Central Executive (CE)?;
Describe its structure or system of processes;
An attention controller that is an interface between WM “slave” systems and long-term memory (LTM) (does not have its own storage capacity);
May be hierarchical (controller at top) with control as the emergent feature (e.g. through mutual inhibition/activation)
What are the functions of the CE?
Co-ordination of the subsidiary (slave) WM systems; control of encoding & retrieval strategies; switching of attention; mental manipulation of material held in the slave systems
Random number/letter generation was thought to require the CE. But under pressure of concurrent CE demands, what do sequences become?;
Baddeley & colleagues have shown interference between random number/ letter generation and what?
Less random
Playing chess; reasoning; problem solving; generating items from semantic categories; mental arithmetic
What does the Phonological Loop do?;
What 2 components does it consist of?
Maintain verbal, sequential information in a phonological (sound-based) code; Verbal store (inner ear) & subvocal articulatory rehearsal process (inner voice)
How soon does information decay in the phonological loop?;
Articulatory rehearsal also may be used to enter information into the store. Give some examples of these
After about 2 sec, unless maintained by rehearsal;
Remember phone number, recipe, instructions, in the short term; digit span
List the 4 key effects of the phonological loop
Phonological similarity effect; Irrelevant (unattended) speech effect; Word length effect; Concurrent articulation effect (also called articulatory suppression)
What evidence did Conrad & Hull find in support of the Phonological Similarity Effect?
Most confusion/errors in immediate serial (ordered) recall for letters with similar sounding names (e.g. B, G, V, P, T)
Baddeley tested serial recall of phonologically similar vs. dissimilar 5-item sequences presented auditorily (e.g. mad, man, mat, cap, cad) & a control pool (cow, day, bar, few, hot). What was the difficulty in the similar condition?;
Is the effect due to the sound or spelling of the word?
Recalling order information (similar results for visual presentation);
Sound (effect found with caught, sort, taut, etc)
What do confusions among phonologically similar items indicate?;
What does an absence of the phonological similarity effect suggest?;
Is it a characteristic of LTM or WM?
Use of phonological representations;
That participants have abandoned a phonological coding strategy;
WM (LTM usually shows semantic not phonological confusions
Describe the Irrelevant Speech Effect (or unattended speech effect);
Does it depend on the meaning of the material?
Speech impairs serial verbal recall of visually presented material;
No, nonwords, Arabic and backward speech interfere (music sometimes interferes; white noise has no effect; intensity of auditory stimulus unimportant)
What’s Baddeley’s interpretation of the Irrelevant Speech effect?
Obligatory access of speech-like input to phonological store; corruption of trace/added noise, rather than phonological confusion effect (can get impairment for materials that don’t produce a phonological similarity effect)
Dylan Jones has an alternative view about the Unattended Speech effect. What is it?;
Instead, he proposes the Changing State Model. What is this?
There’s no privileged access for speech; can also get interference with tone sequences & music; don’t get interference with repetition of a single speech sound;
Elements in the study list may become linked to elements in the irrelevant speech stream, which impairs order information; it depends on the pattern of changes between 2 sound streams
Describe the Word Length Effect;
What evidence did Baddeley, Thompson & Buchanan, find for this?
Immediate memory span declines with the spoken duration of the list items; (span is the largest number of items than can be correctly recalled in order);
They presented participants with short auditory lists (e.g. sum, hate, harm, wit) & long ones (e.g. association, opportunity, representative), & more short word sequences were correctly recalled
When Baddelely et al. controlled the number of syllables, what did they find?
Lower accuracy for items with longer-duration pronunciation, not about syllables
What does the Word Length Effect reflect?
Rehearsal involves central programming of speech but not what?
The speed of subvocal rehearsal and hence the rate of refresh of the memory trace;
Output (patients without vocalisation show rehearsal, but not those with impaired speech programming)
At what age does the Word length effect begin?
In children around 4 years (developmental increases in speech rate are associated with increases in verbal recall)
Cowan has an alternative view about the Word Length Effect. What is it?;
How do other studies contradict this view?
Delays at output are associated with the longer articulation time of long items;
They show the same deficit even with probed recall (e.g. was the item “representative” in position 3?)
What evidence has been found in support of Concurrent Articulation (articulatory suppression)?;
How has this effect been interpreted?;
What components of articulation are important?
Repeating la-la, or hiya etc, adversely affects serial recall & abolishes the word length effect; the phonological similarity effect is removed by articulation with visual but not auditory presentation;
It eliminates subvocal rehearsal & impairs phonological recoding of visual material;
Hearing speech is not a major factor; silent articulation interferes, but not non-speech actions (chewing, etc)
What is the Phonological Loop for?;
Brain injured patients with severely impaired verbal serial recall can understand and read most sentences except perhaps what?
Vocabulary learning in children, or learning a new language; comprehension of oral and written language, but only as a back up;
Very complex and “garden path” sentences (e.g. the horse raced past the barn fell)
Visuo-spatial encoding rather than verbal encoding of material is perhaps processed in which lateral hemisphere?;
What tasks have been used to analyse the Visuo-spatial Sketchpad?
Right hemisphere;
Corsi tapping task, memory for un-nameable shapes/patterns, navigation & tracking
What did Brandimonte & Hitch (1992) find about concurrent speech with visuo-spatial tasks?;
What does Baddeley suggests that V-S memory is based on?
Concurrent speech impairs verbal encoding of shapes (e.g. “umbrella”), but does not affect visuo-spatial encoding of shapes;
A visuo-spatial code that supports imagery
Consistent with imagery research, Baddeley has recently divided the V-S sketchpad into which 2 components?
Visual cache, which stores visual patterns (e.g. layout of forms, shapes, etc); & Inner-scribe - spatially based rehearsal (e.g., of movement sequences - doesn’t require visual input; can be performed by blind participants)
What did Logie & Marchetti find in relation to links between motor control & memory for spatial & visual patterns?
Arm movements in retention interval disrupt memory for spatial patterns but not visual (colour) information; visual interference task affects memory for colours but not spatial patterns
According to neuropsychology, there’s a separation between knowing what an object is and knowing where it is. What did Hitch et al. find in regards to figure-ground information?;
What does this suggest about V-S memory?
Unmatched/different figure-ground information for 2 conjoinable figures impairs detection of conjoined figure in working memory task, compared to matched figure ground information
Organisation of V-S memory occurs at the level of objects
Describe the functions of the Visuo-Spatio Sketchpad
Planning and execution of spatial tasks (e.g. sport, driving, etc); manipulating visual images (e.g. in skilled abacus users); keeping track of changes in the visual perceptual world; maintaining orientations in space and directing movement; comprehending certain verbal information (in navigation etc)
The Baddeley model describes and organises some key facts about human short-term memory. What are they?;
What’s a limitation in this model?
Limitations of memory; coding & modality effects;
Insufficient development of how the stores interact and the interplay of WM and long-term memory
Where Baddeley’s model is structural & focuses on passive stores, what do alternative models emphasise?;
Capacity & active processing (e.g. operation span task by Engle et al.); & span score, determined as longest sequence that can be recalled to a specified criterion; (used in individual differences research)
According to Cowen’s (1998) theory, the idea of transfer of information into and out of stores does not capture what?;
What does he claim about LTM’s role?
The dynamic nature of WM;
Part of LTM memory is active in WM to meet the demand of the current task (e.g., text comprehension) this is accessible by fast-acting retrieval cues
What brain networks do WM involve?;
What does WM function depend on?
Fronto-parietal (pure storage in posterior parietal lobe; rehearsal and executive functions in frontal lobe);
Activation by neurotransmitter dopamine, with regulation by inhibitory neurons
According to Karlsgodt et al., Behavioural Brain Research (2011), to what extent is WM capacity genetically determined?
WM is highly heritable; genes identified for effects on neurotransmitter function & brain morphology (white & grey matter integrity) in the WM network; several separate biological causes of WM deficits
