Problem 5 Flashcards
CB + IB findings suggest that we have a limited conscious representation of the outside world due to selective processes, by which some items are privileged over others.
There are 3 theories surround this, providing an explanatory basis.
Name them.
- Theory
- Theory B
- Theory C
- Theory D
Theory A
Suggests that when many sensory inputs reach the brain, attention plays a crucial role in the selective process
–> allows only some of the inputs to reach a conscious state
Theory B
Suggests the same as A, but adding unconscious processing to it
–> there are therefore 3 levels of processing of visual inout
- unconscious
- unattended
- attended
BUT: it is said that there is no difference between unattended + unconscious, thus identical
Theory C
Eliminates the word conscious, but equates it to attention
–> relies solely on attention
Theory D
Proposes that attention doesn’t determine whether a stimuli reaches a conscious state but whether
a) a conscious report about a stimuli is possible
b) items are stored in a stable manner in WM to report at a later time
Attentional selection
Refers to a mix of memory + processing
–> necessary when 2 stimuli reach the brain but only one response is possible
Competition
Occurs on the level of the extra striate areas
–> prevents all inputs from reaching the output areas of the brain
Name the reasons for which a stimulus may be selected over others.
- More salient (neutral stateI
- -> associated neural activity in response is stronger + more synchronous - Effect of previous stimuli (biased state)
Feedforward sweep
FFS
Refers to the earliest activation of cells in successive areas of cortical hierarchy
–> casual processing mediated hereby is not accompanied by awareness
Phenomenal wareness
Refers to qualia
..> “what it is like” to experperience a certain “state”
Phenomenal wareness
Refers to qualia
–> “what it is like” to experience a certain “state”
Access awareness
Involves
a) availability
b) reportability
c) behavior
as a result of access to a certain state
BUT: it is limited to a few items in the scene
In a situation where multiple stimuli are presented, all stimuli are represented at early stages of FFS
At hier extra striate areas, receptive f. become too large + competition arises
As not all stimuli can be processed by the receptive field a certain phenomenon arises.
Name it.
Crowding phenomenon
–> individual awareness of closely spaced items is impaired
What resolves competition between multiple stimuli and thus the crowding phenomenon ?
Attentional selection
–> can operate on the level of
- FFS, by predisposing some interactions over others
- Recurrent interactions
Is attending to an object the same as becoming conscious of it ?
No,
one can attend to an object without becoming aware of it
–> as seen by visual consciousness vs attention
THUS: the 2 are supported by distinct neuronal mechanisms, which is supported by the studies of Watanabe + Maier
Visual consciousness
Refers to the contents of conscious experience
Visual attention
Refers to the process that directs a tiny portion of the info arriving at the V1 to high-level centers involved in visual WM + pattern recognition
Watanabe did an experiment where attention + consciousness were manipulated.
How did they proceed ?
- Participants were placed in fMRI while looking at
a) target (moving grating)
b) suppressing annulus
- Both stimuli are either projected to
a) one eye, making them visible
b) different eyes, making them invisible
- To assess attention participants should
a) identify when a certain letter occurred in a stream of letters
b) attend to target grating + ignore flashing letters
What was the result of the Watanabe experiment ?
BOLD single amplitude in V1 was
a) not consistently modulated by the visibility of target
b) consistently increased by when attention to the target was payed regardless of its visibility
Block design
Refers to an experiment whereby a short burst of invisible motion is repeated many times to constitute many invisible trials
Block design paradigm
Involves a 16s stimulus block followed by a blank display of a varied period
–> each stimulus block contains 16 presentations of visible/invisible stimuli; ratio of 2 stimuli was 14:2
