attention and consciousness Flashcards
what is inattention blindness? (Mack & Rock 1988)
Often even otherwise fairly salient events in the environment go unnoticed if not in the focus of attention
what is Change blindness? (Simons & Levin, TICS 1997)
Often even drastic changes in the environment go unnoticed if not in the focus of attention
In scenes like this, approx. 50% of the population will not notice the change (depending on the saliency of the difference) of the person they’re talking to
what is the cocktail party phenomena?
- supports selective attention
- The phenomenon wherein the brain focuses a person’s attention on a particular stimulus, usually auditory.
- Enhancing relevant informationFiltering out distracting information
- Theories of early vs late selection:
- Are attended stimuli more saliently represented, or is it the later processing that is altered?
- 1960s and 1970s, relation to consciousness
what is the “Posner-paradigm”?
- a neuropsychological test often used to assess attention. Formulated by Michael Posner, it assesses a person’s ability to perform an attentional shift. It has been used and modified to assess disorders, focal brain injury, and the effects of both on spatial attention.
- Participants are required to keep their eyes fixated and this is being measured (eyetrackers)
what is exogenous attention?
- Attention captured by external events in the environment (e.g. sudden appearance of a salient stimulus)
- In an experiment: driven by cue that has a physical similarity with a task-relevant (target) stimulus, e.g. flashing at the same location before
what is endogenous attention?
- Attention allocated according to behavioural goals or predictions about events in the environment
- In an experiment: usually driven by explicit instructions which stimulus is relevant (and which to ignore) or what kind of stimulus can be expected (probabilistic cueing). The cue shares no physical similarity with the target (e.g. does not show up at the same location!)
what is the dorsal system?
“Goal-driven”, based on predictions about what will happen in the environment and what is relevant to achieve current behavioural goals
what is the ventral system?
“Stimulus-driven” – responding to events of the environment and important for “breaking” up current attentional allocation
what is hemispatial neglect?
- reduced awareness of stimuli on one side of space, even though there may be no sensory loss
- e.g. Patients with lesions (e.g. due to stroke) to their right parietal, frontal and temporal lobes experience a loss of sensory awareness of their left “hemifield” (primarily visual, but also auditory)
- This is not due to a “visual” deficit, i.e. in their eyes or visual cortex, but an attentional deficit
what is blindsight?
- a phenomenon where, not entirely unlike spatial neglect, despite having completely intact eyes, a patient has lost vision or conscious awareness
- this may affect part of their visual field or reflect a complete loss of (conscious) vision
who initially studied blindsight?
Riddoch (1917, Brain): “Dissociation of visual perceptions due to occipital injuries, with especial reference to appreciation of movement“
what is the where pathway?
for spatial analysis of scenes (location and spatial relations between objects)also sensorimotor functions – grasping movements etc
what is the what pathway?
for detailed object recognition, “semantic analysis”
what makes up the visual pathway?
extra geniculate-striatal pathways and the dorsal vs ventral pathway
what happens in the blindsight pathway?
- Bypassing V1, which is damaged in Blindsight patients and necessary for phenomenal awareness
- Some (gross) spatial information present in the collicular-pulvinar-dorsal pathway
