LECTURE 5 - Cognitive Control/Working Memory Flashcards
what is cognitive control?
- also known as executive control
- ability to orchestrate thought and action in accordance with internal goals
- allows us to plan, decide, and select behaviours and coordinate multiple actions in parallel
- it can be proactive (in anticipation of an event) or reactive (during an event)
how is cognitive control related to attention?
- cognitive control requires attention
- internal attention determines how much information can be prioritized within the mind
- cognitive control allows us to prioritize and manage the competing demands from our environment (external attention) and from within our mind (internal attention)
what factors determine whether we can multitaks effectively?
- cognitive load: the difficulty of a task
- cognitive overlap: how much the demands of simultaneous tasks compete for the same mental resources
* ex. low competition when listening to music and walking, high competition when texting and walking
how are cognitive load and overlap measured? how does cognitive interference play a role in these tasks?
- measured in the lab with dual-task experiments
- observers are asked to engage in two tasks simultaneously
- performance suffers due to cognitive interference, either when cognitive load is high or when the two tasks overlap
- cognitive interference determines how well people will do on the tasks
how does cognitive load differ during automatic vs. controlled processes? how do PFC lesions affect cognitive control?
- when we perform a task that requires only minimal cognitive effort, most underlying cognitive processing is automatic
- when we perform a task that requires more cognitive control, the cognitive load is much higher
- controlled processes recruit brain areas in PFC to exert supervisory attentional control
- lesions in PFC impair cognitive control and may lead to perseverance errors (inability to switch task rules)
what is inhibition?
- central function of cognitive control
- is the ability to suppress information, thoughts, or actions that may interfere with ongoing behaviour
- inhibition also reduces distraction and allows us to focus on the task at hand
how is inhibition measured in the lab?
- ability to inhibit actions and impulsive behaviours can be measured using the stop-signal tasks
- at baseline, green dot is the go cue and measures reaction time
- experiment: red dot is the stop cue, shows up after the go cue
- people are able to inhibit well when there is a stop cue
- if the stop cue comes early, they can still stop their behaviour
- if the stop cue comes later, it is harder to stop behaviour because they are already doing it
what is the stroop task and what does it measure?
- say the colour of the words without reading the words themselves
- harder when the word meanings conflict with the ink colour (stroop interference)
- stroop tasks requires selective inhibition for cognitive control
what is the simon task (or spatial interference task)?
- a way to test response conflict
- spatial incompatibility exists between target location and the responding hand, which slows response time
- observers fixate on the middle of a screen while a target can appear to the right or left
- compatible condition: subjects press left or right when the target is left or right
- incompatible condition: observers press a button opposite to the side of the target (harder and requires more cognitive control)
what is the flanker task?
- examines two types of interference: perceptual interference and response interference
- flanker words or symbols are automatically processed and need to be inhibited when they are incompatible
- when flankers are incompatible, a conflicting response is elicited and needs to be suppressed, this causes slowing in processing and slower response times
- different types of flankers cause different types of interference
- perceptual interference occurs hwen the flankers are closer to the target
- response interference occurs when distractors offer a conflicting response
what happens in cognitive control when a task causes interference?
cognitive control has two possible functions when a task causes any type of interference
* conflict monitoring: detects interference
* conflict resolution: to reduce interference, allows observers to continuously monitor and correct their actions
what brain area is responsible for conflict monitoring?
- anterior cingulate cortex (ACC) is the central conflict monitor in the brain
- ACC is active during all interference tasks
- ACC performs error detection and is active when prediction errors occur
what brain area is responsible for conflict resolution?
- dorsal PFC is important to resolve conflict
- inhibits distracting interference
- DLPFC activity correlates with task performance in interference tasks
- ex. the more active the DLPFC, the smaller the stroop interference
what is the switch cost?
speed and accuracy penalty that comes with having to switch tasks
what is the preparation effect?
if advance knowledge is given about the task, and time allowed to prepare for it, the average switch cost is usually reduced
what is residual cost?
even with long delays with ample time to prepare for the next target, the task-switch cost does not completely go away
what is working memory?
brain system that provides temporary storage and manipulation (cognitive control) of information necessary for complex cognitive tasks
what do storage and manipulation refer to in regards to working memory?
- storage: maintains info when it’s no longer available in perception, a form of internal attention
- manipulation: allows the mind to do operations and transformations of information
what are the three components of working memory?
- visuospatial sketch pad: holds/manipulates visual and spatial information
- central executive: controls and manipulates information, sets goals, directs attention
- phonological loop: stores and rehearses verbal content (speech, sounds, words)
what is the episodic buffer in working memory?
- combines information from multiple internal sources into and episodic representation
- ex. visual info from visuospatial sketchpad, auditory info from phonological loop, long-term memories
- thought to be the fourth aspect of working memory
what is some empirical evidence for the structure of working memory?
- dual-task studies: interference in dual task studies is smaller if info does not overlap, suggesting separate storage systems must exist
- brain imaging studies: different types of brain lesions differentially affect performance in verbal and spatial memory tasks, suggest storage systems are anatomically separate
what exactly is the central executive aspect of working memory responsible for?
- command center for working memory, does all the work of cognitive control
- response selection, task switching, supports decision making and planning
- brain imaging studies show DLPFC is more active when we are tasked with reordering letter sequence than when we are asked to remember it
what are the two components of the phonological loop? how is their capacity tested?
- phonological store: holds sound or speech based information for 1-2 seconds
- articulatory rehearsal loop: where you perform inner speech
- capacity is tested with digit-span task
- observer repeats back series of numbers to determine capacity of articulatory rehearsal loop
how can be increase the capacity of our phonological loop?
- chunking can increase our capacity limit to seven plus or minus two chunks
- rather than seven plus or minus two items
- ex. chunking 9-1-7-4-5-3-3-5-1-4 to 917-453-3514
what does the capacity of the phonological loop look like for verbal information?
- word-length effect: working memory capacity for words depends on duration or syllable length of the words
- longer words take longer to rehearse in phonological loop, leading to increased decay and poorer recall
- performance is also related to reading and speaking rats, people who read/speak faster have greater working memory capacity
what is the acoustic similarity effect?
- there is a reduced capacity of working memory for items similar in sounds, compared to items that are dissimilar
- observers find it harder to remember “man, cap, can, map, mad” compared to “pit, day, cow, pen, rig”
what is the irrelevant speech effect?
- working memory is impaired by irrelevant spoken material irrespective of its meaning
- it is the sound that interferes, not the meaning of the words
- background speech—even when ignored—interferes with the phonological loop in working memory
what is the visuospatial sketch-pad? what is its capacity?
- also known as visual short-term memory
- retains visual information over time, especially when the perceptual image is no longer available or has changed (when we move our eyes)
- stitches together information from one fixation to another
- capacity of the visuospatial sketchpad appears to be four features or objects, where several features can be chunked into an object
what is the visual short-term memory task developed by Luck and Vogel (1997), and what does it test?
- participants see a display of colored, oriented bars
- after a 90 ms blank gap, a second display appears
- they must decide if the two displays were the same or different
- items vary by colour only, orientation only, or both
- accuracy drops as the number of items increases (set size)
- but remembering combined features is no harder than single features
- shows that visual working memory stores whole objects, not separate features
what are some theoretical ideas about how the visuo-spatial sketch-pad stores complex real-world objects?
- slot model: each slot in visual short term memory corresponds to one object, up to four objects can be stored, regardless of how complex they are
- resource model: capacity is a limited resource that is shared by all objects, capacity correlates with object complexity
- brain imaging data supports both
how are long-term and working memory independent but also related?
- long-term memory has greater capacity and durability than working memory
- attention selects relevant info from long-term memory according to task and transfers them to the episodic buffer in working memory
- working memory is a selective activation of long-term memory
cognitive control allows a person to…
a. calculate tax payments while someone is talking to them
b. passively experience moving scenes
c. receive a coded message
d. complete a complex math problem
e. breathe while talking
a. calculate tax payments while someone is talking to them
