1. Visual Attention 1 Arash Afraz

2. “Visual Selection” might be a better term

3. Do we really see without attention?
Inattention Paradigms
Attentional Blink
Change Blindness
Intentionally Ignored Information

4. Change Blindness

5. Change Blindness

6. Hey Arash don’t forget more demos!

7. What we think we see!
What we really see!

8. Visual Attention (selection)
Overt Visual Attention (eye movements)
Covert Visual Attention

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

10. Physiological Nystagmus
Preventing from stabilizing the image
Random walk movements

11. Physiological Nystagmus

12. Saccadic Eye Movements
Very Rapid ( ms planning and action) (900 degree per second)
Ballistic Movements

13. Saccadic Eye Movements

14. Saccadic Eye Movements Saccadic Suppression
Motion Blur Problem
“Too Fast Motion” explanation!
“Visual Masking” explanation
Is it a real problem!?

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

16. Vergence Movements
Slow (10 degree per Sec)
Diconjugate

17. Vestibular Movements Head is not still! Faster than pursuit
Mostly unconscious
Controlled by vestibular system

18. Optokinetic Movements
Involuntary tracking of large field movements
Bi-phasic (slow-fast)
Vertigo!

19. Contextual Effects in Eye Movements

20. 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
Covert Visual Attention…

21. To be continued!