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.
