Attention 2 Flashcards
What is the term used to describe the failure to acknowledge stimuli on the contralesional side of the lesion and only acknowledge stimuli on the ipsilesional side of the lesion?
(Hemispatial) Neglect
Explain Hemispatial Neglect
The failure to acknowledge stimuli on the contralesional side of the lesion and only acknowledge stimuli on the ipsilesional side of the lesion
What causes Neglect?
Lesion/damage on the right hemisphere of the brain
What lesion specifically causes Neglect?
Right parietal damage to the brain, following a stroke (blockage in brain rather than a bleed out)
What do Neglect patients do?
- They only acknowledge things/surroundings on the right side, which is the same side of the brain as their lesion
- e.g. They only eat on the right side of the plate
- e.g. They only draw on the right side of the papar
What is a patient with hemispatial neglect likely to do when presented with a line-bisection task?
Bisect the lines to the RIGHT of the centre
Describe 3 features of the border between neglected space and non-neglected space
1) It’s a gradient, not sharp and fuzzy (not entirely black as it is a loss of attention, not vision)
2) Does not necessarily align with the middle of the stimulus (vertical midline, it depends on the display)
3) Can vary with the number of distractors in the display
Is anything processed when there’s neglect?
Yes - Some unwanted semantic information (info with meaning)
But - Patients may not be consciously aware of the neglected stimuli
Marshall and Halligan
Who conducted the Piazza Del Duomo experiment for Neglect?
Bisiach and Luzzatti
Describe the Piazza Del Duomo experiment for Neglect
- Patients were told to picture themselves standing on one side of the Piazza Del Duomo
- Patients were asked to describe what they remember of the Piazza
- They described the right side of the Piazza only
- Patients were told to “walk over” to the other end of the Piazza and describe their surroundings
- Again, they described the right side of the Piazza, only now it was based on what they saw on the other end of the Piazza
What is a visual search?
Looking for something in a clustered visual environment
What are the 2 types of visual search?
Serial and Parallel search
What is a Parallel Visual search?
Visual search process that focuses on multiple items at once
What is a Serial Visual search?
Visual search process that focuses on one item at a time
If reaction time is affected by display size, it is a … (parallel/serial) visual search
Serial
If reaction time is not affected by display size, it is a … (parallel/serial) visual search
Parallel
If there are no effects of display size at all it is a …
Pop out
Why is it that if the reaction time is affected by display size, it is a serial visual search?
- Because if the display size is large, you would have to go through each item one by one
Why is it that if the reaction time is not affected by display size, it is a parallel visual search?
- Because no matter the display size, if the distractors share similar traits that contrast with the attended/target item, you can attend to all items at the same time
What is the term used to describe when there is no effect of display size at all?
Pop out
Who proposed the Feature Integration Theory (FIT)?
Triesman and Gelade
What does the Feature Integration Theory (FIT) suggest?
The visual search is a two-stage process
List the 2 stages of the Feature Integration Theory (FIT)
1) Preattentive stage
2) Focused attention stage
Feature Integration Theory (FIT) suggests that visual search is a two-stage process. What is the role of the preattentive stage?
Process physical and basic characteristics of the search items
The Feature Integration Theory (FIT) involves 2 processes. Which process is fast and which is slower?
1) The first stage (Preattentive) is fast
2) The second stage (Focused Attention) is slower
Describe the results of the Feature Integration Theory (FIT) study
- Conjunctive targets (when targets share one of their traits with the distractors) require more attention
- Illusory conjunctions occur due to problems in combining features at a late stage
- The set size affects conjunction target search but not single target search
What are conjunctive targets?
When targets share one of their traits with the distractors (e.g. Target is the letter ‘T’ but it shares the colour ‘Green’ with the distractor letters
Which stage of the FIT requires focused attention?
Focused attention stage
Which stage of the FIT does not require focused attention?
Preattentive stage
Which stage of the FIT is faster than the other?
Preattentive stage