visual attention 1 arash afraz
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Visual Attention 1 Arash Afraz. “Visual Selection” might be a better term. Do we really see without attention?. Inattention Paradigms Attentional Blink Change Blindness Intentionally Ignored Information. Change Blindness. Change Blindness. Hey Arash don’t forget more demos!. - PowerPoint PPT PresentationTRANSCRIPT
Visual Attention 1
Arash Afraz
“Visual Selection” might be a better term
Do we really see without attention?
• Inattention Paradigms
• Attentional Blink
• Change Blindness
• Intentionally Ignored Information
Change Blindness
Change Blindness
Hey Arash don’t forget more demos!
What we
think we see!
What we really see!
Visual Attention (selection)
• Overt Visual Attention (eye movements)
• Covert Visual Attention
Eye Movements
1. Physiological Nystagmus
2. Saccadic Eye Movements
3. Smooth Pursuit
4. Vergence Movements
5. Vestibular Movements
6. Optokinetic Movements
Physiological Nystagmus
• Preventing from stabilizing the image
• Random walk movements
Physiological Nystagmus
Saccadic Eye Movements
• Very Rapid (150-200ms planning and action) (900 degree per second)
• Ballistic Movements
Saccadic Eye Movements
Saccadic Eye Movements Saccadic Suppression
• Motion Blur Problem
• “Too Fast Motion” explanation!
• “Visual Masking” explanation
• Is it a real problem!?
Smooth Pursuit
• Slower Than Saccade (100 degree per sec at maximum)
• Smooth (not jerky)
• Feedback (not ballistic)
• Acuity (importance of smooth pursuit in biology)
Vergence Movements
• Slow (10 degree per Sec)
• Diconjugate
Vestibular Movements
• Head is not still!
• Faster than pursuit
• Mostly unconscious
• Controlled by vestibular system
Optokinetic Movements
• Involuntary tracking of large field movements
• Bi-phasic (slow-fast)
• Vertigo!
Contextual Effects in
Eye Movements
Covert Visual Attention…
• How to select target of next saccade?
• There are some social conditions in which we can’t shift our attention overtly
• Attending to more than one item
To be continued!