Chapter 4 Defining Attention Flashcards
What is attention?
- Process by which some information is selected for further processing while other information is discarded
-Limited capacity to process all information so selection based on relevance to current goals - Can be directed to locations in space
-Spotlight metaphor - May be needed to integrate different aspects of
conscious perception
-Feature binding function
Why do we need attention?
- We can choose to pay attention to aspects of the
world
-And appear to be oblivious to other things - We not only perceive the world, but also act on it
in the service of plans and goals
-This requires focus or attention
Questions:
-How do we channel relevant from irrelevant?
-How do we direct attention to accomplish a goal?
Inattentional blindness
- Failure to perceive something in scene
- Not expecting
- Attention is focused elsewhere
Change blindness
- Observers do not retain many visual details from one view to the next
- We get the gist of scene and ignore the visual details; if the gist stays the same, change detection is unlikely
- Changes in center of scene detected more readily
- E.g. In change blindness studies, people fail to notice a change in the identity of the person asking directions.
Neural areas involved in attention
Anatomical model of spatial attention
- Dorsal Fronto‐Parietal System
-Preparatory and voluntary goal‐directed attention
-Bilateral distribution - Ventral System
-Detection of salient unexpected stimuli; mediates interruption of attentional focus mediated by the dorsal system
-Lateralized to the right hemisphere
Dorsal and ventral attention networks
Spatial:
- Preparatory and voluntary goal‐ directed spatial attention
- Bilateral distribution
- Not Asymmetric
Nonspatial:
- Detection of salient unexpected stimuli
- Arousal and vigilance
- Mediates interruption of attentional focus controlled by the dorsal system
- Disengagement/Reorienting Attention
- Lateralized to the right hemisphere
RH dominance of neglect reflects the laterality of the ventral network mediating
nonspatial mechanisms of arousal, detection, and reorienting
- Not the laterality of dorsal network mediating spatial attention
Hemispheric differences in attention
The right parietal lobe supports richer spatial
representation
-left + some right space
The left parietal lobe provides an impoverished spatial
representation
-predominantly right side of space only
- Greater spatial specialization of the right parietal lobe means:
-Tendency to attend to the left side of space (pseudo‐neglect)
-More severe problems with right parietal lobe damage than with left parietal damage (left side neglect)
Neglect syndrome: Unilateral Parietal Lobe Damage
- Ignores information from the left side of the space
- eats food from one side of the plate
- washes only half of the face
- fails to locate objects if on the neglected side
- reading words like pigpen or parties reads pen or ties
- Characterized by a failure to attend,
respond or orient to stimuli on the side
opposite of lesion
-Not fully accounted for by sensory or motor loss
How do we know whether neglect is an attentional deficit or a perceptual deficit?
- Let’s exploit what we know about the visual system and priming.
- Left visual field (LVF) goes to the right hemisphere (RH)
- Right visual field (RVF) goes to the left
hemisphere
Semantic Priming Paradigm
Other that neglect patients are still perceiving the stimulus (it’s an attention deficit, not a perception deficit)
- Objects in neglected space activate the appropriate
visual regions in occipital lobes - Neglect patients are often able to detect objects on
the left if cued there - Affects auditory and tactile judgements as well as vision
- Phenomenon of visual extinction suggests different
perceptual representations are competing for
attention (& visual awareness)
Is neglect spatial or object based? Scenario if spatial-based
If spatial-based: the
left side of space
should be ‘ignored’
Is neglect spatial or object-based? Scenario if object-based
If object-based: the left
sides of objects should
be ‘ignored’, even if
there are several
objects
Patient’s copy of flower
Different types of neglect diagram
