1. Visual Attention

2. How much information can we process?

3. Can we process everything we see? Increase sensitivity to certain stimuli and decrease sensitivity to others Attention works in space and time

4. Can we process everything we see? Attention consists of a variety of selection mechanisms Orientation Selection Sustaining

5. Visual Search Attention in space Example Target and distracter

6. Visual Search Parallel Search  Object pops out  Search time independent of number of distracters

7. Visual Search Serial Search  Less efficient  Search times depends on the number of distracters

8. Attending it time Rapid serial visual presentation (RSVP) Attentional blink Difficulting in perceiving a second of two target stimuli.

9. Do Video Games Improve Attention? Green and Bevalier (2003) nature Compared video game players and non video game players on spatial and temporal attention tasks. Attentional blink

11. Do Video Games Improve Attention? Green and Bevalier (2003) nature Non video game players One group did a shooter game the other did tetris. 10 1 hour sessions. The shooter group did better on attention tasks.

12. How do we perceive change? http://www.youtube.com/watch?v=Qb- gT6vDrmU

13. Perception of Scenes or Pictures Change blindness  Difficulty perceiving subtle changes to a scene of pictures over time.  If the meaning does not change may be hard to perceive the change.

14. Measuring visual attention Tests of visual attention  Trail making test  Symbol digit modality  Test of Silent Word Reading

19. Test of Silent Word Reading Fluency Child separates words that run together Ofgoliketwobig Of/go/like/two

21. Disorders of Visual Attention Visual field deficit  Is a measure of attention in space Visual neglect Difficulty attending to items in one part of space Typically in left field

23. Visual Neglect Hemi-inattention  Lack of awareness of one side of space Hemispatial neglect  Similar term  Can include formal tests of neglect

24. Visual Neglect Allesthesia  Tendency to mis-locate stimuli presented on the affected to the non-affected side.  When touched on the left shoulder report stimulation of the right arm.

25. Visual Neglect Extinction  Can see an object when one side is stimulated  Will fail to see the same object when both fields are simultaneously stimulated.  Can be in more than one sensory modality- touch

26. Visual Neglect Anosognosia  Lack of awareness of the difficulties  For example, patient is unaware that they had a stroke and paralysis of the left side.

27. Examples http://wn.com/hemispatial_neglect

28. Visual Neglect Body (personal) space  Do not groom left side Reaching (peri-personal) space  Difficulty locating objects within arms reach Far (extra-personal) space  Difficult describing distance objects

30. Tests for Neglect Line Bisection  Shift toward side of the lesion  Patient essentially bisecting a shorter line  Shift of visual space (midline shift)

31. Tests for neglect Copy figures  Will miss details on the left side

33. Tests of Neglect Balloon Test

35. Tests of Neglect Behavioral Inattention Test  6 traditional tests  9 behavioral tests  Norm data for neglect patients

37. Balint Syndrome Bilateral lesion of the parietal lobes Poor at spatial localization Fixed gaze See one object at a time – Simultagnosia