cognitive Flashcards
view of the mind/body problem - type identity theory
a mental state’s equivalent to a specific pattern of neural events
cannot be true- neural patterns differ in ppl performing the same event
view of the mind/body problem - functionalism
distinction between structure of a mental state & function of a metal state
Information processing analogy for thought
input -> processing -> output
brain runs like a computer
cognition = the processing of these internal representations
the computational metaphor for thought
assumes:
the mind contains symbolic representations (limited & well-defined set of symbols stored in memory that represent something in the real world)
cognition’s the product of operations (internal processes that act on symbolic representations - deployed according to rules stored in memory)
3 levels of description for cognition
Marr, 1982
- computational theory level- function of cognition
- representation & algorithm- how does cognition work
- hardware level- how are representations instantiated in the real world
Modularity I theory (Marr, 1982)
human cognition’s composed of modules that have a specific function/process
cognitive activity is comprised of the activation of several independent modules
damage to 1 module doesn’t necessarily affect processing of other modules
modules correspond to brain areas
modules are similar across humans
Modularity II theory (Fodor, 1983)
distinguished input systems & central processes.
input/output systems- process incoming sensory info & transfer info to processors. domain-specific
central processor- make decisions, plans actions, isn’t modular
how to identify modules
dissociation - manipulation that affects 1 cognitive task & not a different task
double dissociation - articulatory suppression disrupts verbal & not spatial memory, making saccades (eye-movement) disrupts spatial, but not verbal memory)
~ controlled by different modules
what is cognitive neuropsychology?
brain damage participants- can tell us about the localisation of functions etc.
limitations - don’t know what’s normal performance for that participant, functional reorganisation, doesn’t tell us when operations happen, & damage is rarely focal
what is attention?
a state in which cognitive resources are focused on certain aspects of the environment rather than on others.
Modular model of attention
3 components
alerting/arousal (central process)
selection/orienting (input module)
executive (central process)
what is the filter theory of attention?
Broadbent (1958)
an early theory of attention proposing that unattended channels of information are filtered prior to identification.
only 1 sensory input’s allowed through the filter
evidence of the filter theory of attention
the cocktail party effect
Shadowing tasks
what is the cocktail party effect?
the ability to attend to one of several speech streams while ignoring others, as when one is at a cocktail party. Research in this area in the early 1950s suggested that the unattended messages are not processed, but later findings indicated that meaning is identified in at least some cases. For example, the mention of one’s name is processed even if it occurs in an unattended speech stream.
Cherry’s shadowing task (1953)
get 1 message in 1 ear and 1 in the other- very little info is attained from the ignored input.
Didn’t notice the language changing/talking backwards or remember words, but noticed a beep
~ unattended info isn’t processed
evaluation of the filter theory
+ accounts for the findings of Cherry
- not all unattended info is lost - the theory doesn’t account for analysis of info from the unattended ear - there’s breakthrough from the unattended ear
what is the attenuation theory of attention?
a version of the filter theory proposing that unattended messages are attenuated (i.e., processed weakly) but not entirely blocked from further processing. According to this theory, items in unattended channels of information have different thresholds of recognition depending on their significance to the individual. Thus, a significant word (e.g., the person’s name) would have a low threshold and, when mentioned, would be recognized even if that person’s attention is concentrated elsewhere (e.g., in conversation with someone else).
what is the spotlight model of attention?
a model of visual attention that likens the focus of attention to a spotlight. Information outside of the spotlight is presumed not to receive processing that requires attention.
what is overt attention?
attention directed to a location with eye-movements (i.e., by directly ‘looking’ at it)
what is covert attention?
attention directed to a location without eye-movements (i.e., without directly ‘looking’ at it).
what is the Posner cueing task?
participants are quicker to detect objects at places that have been cued before (e.g. by an arrow), that is, where previously a salient stimulus has been presented.
what are the 2 systems of orienting attention?
exogenous:
involuntary, stimulus-driven, fast, inferior parietal lobe & ventral frontal regions, transient, inhibitory after-effect
endogenous:
orient to task relevant location, voluntary, goal-directed, slow, sustained, superior parietal lobe
what is the feature integration theory for attention?
a two-stage theory of visual attention. In the first (preattentive) stage, basic features (e.g., colour, shape) are processed automatically, independently, and in parallel. In the second (attentive) stage, other properties, including relations between features of an object, are processed serially, one object (or group) at a time, and are “bound” together to create a single object that is consciously perceived.
what is the binding problem?
the theoretical issue of how the brain perceives and represents different features, or conjunctions of properties, as one object or event - could be feature or conjunction
what is the difference between a conjunction and a feature visual search?
conjunction- identification of a target defined by a combination of two features (e.g., search for a yellow square among red and yellow circles and red squares). Also referred to as serial search.
feature- identification of a pop-out target, defined by a single feature (e.g., search for the only square among a display of circles)
what are illusory conjunctions?
the attribution of a characteristic of one stimulus to another stimulus when the stimuli are presented only briefly. For example, the colour of one form can be attributed to a different form.
what is the zoom lens model of attention
constricted into a highly focused beam (subtending as little as a fraction of a degree of angle) or dilated to even distribution over the entire visual field. Because of limited processing capacities, however, there is a tradeoff between size adjustment and detail: An increase in the area attended results in a decrease in the resolution of detail about stimuli within that area.
what is endogenous attention?
attention that is deliberately applied and controlled by the individual
what is exogenous attention?
attention that is captured by a prominent or salient stimulus—for example, in the peripheral visual field—rather than deliberately applied or focused by the individual.
what is dichotic listening?
the process of receiving different auditory messages presented simultaneously to each ear. Listeners experience two streams of sound, each localized at the ear to which it is presented, and are able to focus on the message from one ear while ignoring the message from the other ear
difference between filter & resource theories of attention.
filter - attention prevents the processing of irrelevant stimuli
resource - attention permits the selection of appropriate responses
Kahneman resource theory for attention
capacity’s related to the level of arousal
resource is used flexibly across tasks (pool of resources = central executive).
what is the capacity limit on attention?
3-4 items
Sperling partial report- P’s could only encode 3-4 letters
change blindness- effect vanished if <3 objects are present
multiple object tracking - less accurate when >4.
loci limit could be up to 4
what is change blindness?
observers often fail to notice large changes to objects or scenes when the change coincides with a brief visual disruption
evidence that attention capacity could be 1 item
Downing & Dodds (2004)
shown 2 shapes - 1 is target & 1 has to be remembered.
do a task, and if memory stimuli doesn’t catch attention, P’s are less likely to remember it (irrelevant for task)
bottleneck in attentional processing
when unattended info is not processed
filter theory- place bottleneck early in processing (attention operates at the sensory level of analysis)
resource theory- late in processing. all info is processed semantically & attention operates at the level of response selection
evidence for early selection (attention)
Shadowing - poor recall for info in unattended ear.
selective looking- miss more evens when 2 videos are overlapped.
change blindness- 2 images switching in rapid succession & can’t see change when you’re not paying attention to the object
inattentional blindness- miss unexpected objects when not paying attention
ERP studies- focus attention between 60 & 100ms if object appears (p1000)
evidence that unfiltered stimuli can be processed
breakthrough during shadowing.
Led to attenuated filter - irrelevant info can pass through filter if capacity’s not filled by relevant info
evidence for early selection from attention affects signal enhancement
attention enhances spatial resolution
attention locations have higher perceived contract
evidence for early selection from neurophysiology
attention modulates responses of early visual areas
attention lowers phosphene thresholds in V1
evidence for late selection in attention
the meaning of a distracting stimuli’s processed (results in stimulus conflict)- e.g. Flanker effects, stroop effect, & negative priming
psychological refractory period- 2 stimuli presented in quick succession & reaction to the 2nd stimuli is slowed (only 1 response can be selected at a time
electrophysiology- P’s can detect an occasional probe stimuli in shadowing task (N1 neurons)
what is the flanker effect?
observer decide what stimuli to focus on - still remember ones they didn’t intend to
what is negative priming?
prior exposure to a stimulus unfavourably influences the response to the same stimulus.
what is the perceptual load theory for attention?
reconciles early vs. late selection
there’s a ‘passive’ limited-capacity filter & an ‘active’ central resource.
the filter processes the perceptual properties of stimuli
the central resource is used for identification & decision making
perceptual load- how hard it is to process perceptual features of a display. A low load means all items in a display pass through the filter & get analysed. A high load means only relevant info passes through the filter.
e.g. less interference when doing a task in a high-load condition.
neurophysiological evidence for the perceptual load theory
perceptual load modulates the activity of early visual areas
there’s higher intensity TMS in the high load task compared to the low load
Single resource theories for attention
there’s 1 pool of cognitive resources that has a limited capacity which is used flexibly across tasks. the pool = attention/central executive
If demands exceed capacity, performance suffers.
Motivation & arousal increase cognitive resources (the resource is only needed for consciously controlled behaviour).