6: Visual Attention Flashcards
What is visual attention?
Serves as a mediating mechanism, enabling us to grant priority of processing to certain aspects of the visual scene.
Focusing on specific objects and ignoring others is what?
Selective attention.
Scanning the fovea over objects of interest allows the visual system a _____ view.
High acuity.
Define saccades and fixations.
Saccades: rapid eye movements.
Fixation: pauses between saccades (~300ms).
What is meant by scene characteristics?
High saliency features grab our attention (e.g. high contrast, bright colors).
What is attentional capture?
High salience feature causes an involuntary shift of attention (sudden movements, loud sounds).
What three factors make up a saliency map?
Orientation, colour, contrast.
_____ often drives the first few fixations, but later scene scanning is influenced by _____.
Saliency; cognitive factors.
Knowledge of what is normally contained in typical scenes is known as?
Scene schemas.
How can interests and goals influence attention?
Different parts of a scene or objects are important for different goals. Same image can contain different tasks (e.g., remember clothing, determine age of subjects).
How do task demands influence attention?
Gaze is directed to various objects with specific timing as the task unfolds.
Eye movements usually precede a bodily motor action by _____.
A fraction of a second.
Attention speeds up _____. _____ reduces reaction times.
Responding; pre-cuing.
Attention alters the _____ of visual stimuli.
Appearance.
Attention enhances the firing of neurons. What does neuronal activity depend on, in this case?
Shape, size, orientation, AND attention.
The boost in firing rate is quite small at the level of the _____, but is bigger in _____. What is the order of this sequence?
Primary visual cortex; higher order visual areas.
V1 → MT → MST.
Attention to objects increases responses of _____.
Specific modules.
What increases BOLD signal in retinotopic maps? What can experimenters do with this information?
Attention to a region of space.
Experimenter can “read” where the subject is covertly attending to.
Attention has been shown to re-shape _____.
Receptive fields.
Attention synchronizes neural activity between areas of the brain. Stimulus 1 activates location A in V1 and location C in V4. Stimulus 2 activates location B in V1 and location C in V4. Activity for sites A and C synchronize when what happens?
Attention is directed to stimulus 1.
What is the binding problem?
How are individual features combined to create our perception of a coherent object?
Describe the process outlined by the feature integration theory.
Object → preattentive stage (features separated) → focused attention stage (features combined) → perception.
Give an example of an illusory conjunction.
Seeing a red Q and a blue T, reporting blue Q.
Define Balint’s Syndrome.
Damage to parietal lobe = difficulties focusing attention on individual objects.
Items that POP OUT are _____. Give an example.
Visual primitives.
Find a red vertical bar amongst green vertical bars.
Pop-out/feature search uses _____ processing.
Parallel/pre-attentive.
Give an example of a conjunction search. What type of processing is used and why is attention required?
Find an “L” among “T”s.
Serial/attentive processing.
Attention is required to bind primitives.
List three highlights of Goldstein’s PSA regarding attention and driving.
Hands-free performance similar to phone-in-hand.
Phone conversation ≠ passenger conversation.
Attribution of carelessness/responsibility.
List the two “blindness” terms regarding attention and define them.
Inattentional Blindness: when attention focused on one task, very salient stimuli that are unrelated to the task sometimes not perceived.
Change Blindness: difficulty detecting changes in scenes.
What is an example of change blindness blindness?
Continuity errors in movies.
Is perception without attention possible? Explain.
Depends on task difficulty.
Perception of “extra” task appears to depend on difficulty of “main” task.
What are distracters? What did Lavie et al. find regarding them?
Task-irrelevant stimuli than can affect performance.
Lavie at al. found distracters have smaller effect in more difficult tasks.
