Visual Attention 1 Arash Afraz

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Visual Attention 1Arash Afraz
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Visual Selection might be a better term
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Do we really see without attention?

• Inattention Paradigms
• Attentional Blink
• Change Blindness
• Intentionally Ignored Information

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Change Blindness
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Change Blindness
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Hey Arash dont forget more demos!
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What we think we see!
What we really see!
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Visual Attention (selection)

• Overt Visual Attention (eye movements)
• Covert Visual Attention

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Eye Movements

• 1. Physiological Nystagmus
• 2. Saccadic Eye Movements
• 3. Smooth Pursuit
• 4. Vergence Movements
• 5. Vestibular Movements
• 6. Optokinetic Movements

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Physiological Nystagmus

• Preventing from stabilizing the image
• Random walk movements

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Physiological Nystagmus
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Saccadic Eye Movements

• Very Rapid (150-200ms planning and action) (900
  degree per second)
• Ballistic Movements

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Saccadic Eye Movements
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Saccadic Eye Movements Saccadic Suppression

• Motion Blur Problem
• Too Fast Motion explanation!
• Visual Masking explanation
• Is it a real problem!?

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Smooth Pursuit

• Slower Than Saccade (100 degree per sec at
  maximum)
• Smooth (not jerky)
• Feedback (not ballistic)
• Acuity (importance of smooth pursuit in biology)

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Vergence Movements

• Slow (10 degree per Sec)
• Diconjugate

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Vestibular Movements

• Head is not still!
• Faster than pursuit
• Mostly unconscious
• Controlled by vestibular system

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Optokinetic Movements

• Involuntary tracking of large field movements
• Bi-phasic (slow-fast)
• Vertigo!

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Contextual Effects in Eye Movements
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Covert Visual Attention

• How to select target of next saccade?
• There are some social conditions in which we
  cant shift our attention overtly
• Attending to more than one item

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To be continued!