Consciousness and attention Flashcards
Conscious
Wakefulness or awareness
Defining characteristics of consciousness
Intentionality - directed towards something
Unity - resistant to division
Selectivity - only contains a fraction of the info it could
Transience - content subject to change in/voluntarily
Change detection paradigm - Vogel
Requires participants to identify whether a change occurs in an image of abstract objects. Performance rapidly declined when number in visual store exceeds 4
Sperling partial-report task
Consciousness can hold much more info
Difference is change detection paradigm is a measure of working or ST memory
Partial report-task is a measure or sensory memory, much higher-capacity by shorter-lived
Inattention blindness demonstrations - Carrasco
We are effectively blind to a stimulus change is our attention is diverted elsewhere.
Carrasco shown that when our attention is engaged in a particular object, our conscious experience of it changes - appears clearer to us
Posner - pre-cueing paradigm
Participants must identify some property of a visual target that can appear in one of several spatial locations. Prior to the target’s appearance, attention is diverted in the form of a transient peripheral cute (flash of light) or a central symbol cue (arrowhead). Engage attention
Exogenous
Transient peripheral cue
Endogenous
Central symbolic cue
Attentional blink paradigm
Attentional resources distributed temporally as well as spatially
2 targets are presented in quick succession in a series of distractors, the second target can go completed unnoticed due to attentional resources being take up by the recognition of the first target.
Global Workspace theory, Baars 1988-1998
Theatre metaphor
Working memory competes for access to the conscious spotlight
Unconscious processes are behind the scenes
Once reached level of consioucness - broadcast to several specialised modules
Pre attentive and automatic
Describe perceptual processing that can occur in the absence of attention or prior to attention being distrubuted
Dichotic listening task
Measure of pre attentive processing
Participants listen to 2 septette auditory streams and shadow one of them. Gross physical characteristics of stimuli can be retrieved from unattended stream - cocktail party effect when you become aware of your own name - suggest even semantic content can be processed to some extent
Bottleneck theory of attentional selection
Unattended info is filtered out quite high up in processing stream
Visual search task - Treisman and the feature integration theory
Determining which characteristics of visual stimuli are processed pre attentively.
A single object amongst a set of distractors will immediately capture our attention if it differs in a single visual feature. Does not happen if the target different in terms of a conjunction of 2 or more features
Theory posits that attention is required in order to bind the separate 2 features of an object into a coherent whole
Disorder of attention: neglect
Damage to the parietal lobe, results in patient being unable to attend to the left-side of space, making the patient unaware of things appearing on this side
Disorder of attention: extinction
Mild form of neglect, patients can be aware of stimuli on left but only when not accompanied by a competing stimulus on the right. Semantic info about neglected item still processed
McGurk effect and the rubber hand illusion
Examples of how our mental representation of the world can be altered by the presence of competing sensory info from different modalities.
Delay of formation of representation
In order to achieve multi sensory integration
Information from different modalities can be combined
Compartmentalisation of function, even within a single modality
e.g. vision - colour and motion processed spatially separately. Perception of each of these can be selectively deleted - achromatopsia and akinetopsis.
Neural synchrony
Neurons that represent the same object fire in a synchronous pattern of activity, whereas those that represent different objects do not
Balint’s syndrome
Fail to integrate information as a coherent whole. Fail to see global arrangement of small details and make more conjunction errors, but not intrusion errors in tasks where there have to report the correct combination of colours and letters.
Shows evidence of the classic Stroop effect - on some level, binding is taking place, but lack consciousness access to it
Goals of neuroscientific understanding of consciousness
Determine Neural correlates of consciousness (NCCs) and create neural models of consciousness
NCC
The minimal set of neuronal events sufficient for a conscious experience - detectable pattern of neural activity that indicates a person is having a conscious experiences.
Binocular rivalry and bistable images
Valuable in identifying NCCs as they can induce a dramatic change in the contents of someones conscious experience without having to interfere with the stimulus or the person.
Pascual-Leone and Walsh used TMS
A technique that disrupts neural activity to show that neural activity in the form of feedback from high-level visual areas to low-level visual areas is necessary in order to experience a perception of motion.
Implicit memory
When past experience of something influences cognition and/or behaviour without any associated conscious experience
Patient HM
Improve mirror-drawing skills without remembering taking part in sessions. Shows a clear dissociation between conscious recollection and procedural memory due to different parts of the brain governing these different abilities.
Priming
When exposure to a stimulus influences responses to a subsequent stimulus with or without conscious experience. Word fragment completion for example, participants more likely to fill in blanks of words they have already been exposed to, even though they don’t consciously remember the words.
Jacoby-Whitehouse effect
Even words that aren’t consciously experienced are nonetheless processed at a high level
Continuous flash suppression (CFS)
An extension of binocular rivalry and involves presenting one stimulus to one eye and a complex, dynamic stimulus to the other. Complex stimulus suppresses the other stimulus.
Brain can discriminate between stimuli that are faces and those that are not. Familiar faces break out of the flash suppression more quickly than unfamiliar faces, suggesting unconscious recognition of facial identity can occur
Ego theories of self
There is a true unidentified and continuous self that is the subject of experiences and initiates decisions
Bundle theories
The sense of self is in fact an illusion and a person is simply a constellation of separate experiences and states
Proto self
Entirely unconscious and simply describes the neural patterns that map the state of an organism at any given time
Core self
An event modifies the photo self and provides us with a sense of self from omomembt to moment
Autobiographical self
Depends on memory and describes our representation of our extended self
Corpus scallum severed patients
Split-brain - 2 functionally independent streams of consciousness
Object in left visual field ensures it is processed in the right hemisphere, but not name as no language production in right, but can draw it in left hand
More able to recognise a picture of themselves in the right visual fields and others in the left
Left = self-related concepts
Right = other-related concepts
Agency
Important aspect of our self - ability to make a decision and act on it.
Libet, EEF
Measured brain activity and found the conscious intention to make a decision is preceded by a neural signal by about 300ms
Readiness potential
Develops from 500ms before an actions made, but decision to make that action only occurs 200ms before the action. Suggests our conscious sense of intentionality and free-will may in fact not be a casual factor in making decisions.
Choice-blindness, Johannson et al
Participants have poor insight into their own decision and their motivations for them.
Participants had to judge which of 2 faces they preferred and given a closer look at their choice and asked to justify and explain. Affected their susbsequenct decisions in the task.
Hypnogogic stage of sleep
Stage leading into sleep - transition from wakefulness to first stages of sleep, hallucinatory experiences common
Hypnopompic stage of sleep
Stage leading out of sleep - transition from sleep to full wakefulness - reduced cognitive functioning: sleep inertia
Stage I
Theta waves
Stage 2
Sleep spindles and K-complexes
Stage 3/4
Delta waves (1 hour to deep sleep)
REM sleep
Beta waves and sawtooth waves
Sleep deprivation
Poor immune system and metabilism
Stickgold et al 2000
Perceptual task sleep deprived do not show performance advantage on subsequent testing
Consolidation of declarative (episodic) memory
Deep sleep
Consolidation of non-declarative (procedural) memory
REM sleep
Dreams
About recent experiences. Surreal = result of the brain trying to consolidate random neural activity in the absence of a constant stimulus - activation synthesis model
Coma
No outward signs of being awake
Persistant vegetative state (PVS)
Sleep wake cycle - wakefulness without awareness
fMRI by Owen et al 2006 on PVS
PVS patients have high cognitive ability that may be take as evidence for awareness. When read ambiguous words, greater activity than non-ambiguous words, suggesting some semantic processing.
Activity in posterior parietal complex when instructed to imagine walking through house
Activity in motor area when instructed to imagine playing tennis
Mental imagery
But not present when the word walk or tennis said, so not a simple priming effect
