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
Does priming still happen if the subject does not remember the words/stimuli with which they were primed?
Yes, although it is possible people remember reading the related sentence earlier, the facilitation that occurs with priming is apparent even when they cannot remember the earlier event or stimulus, demonstrating that it is implicit, or unconscious.
