1. Spatial Attention, Object-Based Attention & Unilateral Neglect Psychology 355: Cognitive Psychology Instructor: John Miyamoto 4/15 /2015: Lecture 03-3 This Powerpoint presentation may contain macros that were used to create the slides. The macros aren’t needed to view the slides. If necessary, you can disable the macros without any change to the presentation.

2. Outline Comment re early and late selection models of attention Spatial attention Object-based attention Unilateral neglect - a pathology of spatial attention Feature integration theory Psych 355, Miyamoto, Spr '15 2 Lecture probably ends here Comment re Early & Late Selection Models of Attention

3. Psych 355, Miyamoto, Spr '15 3 Conclusions: Early versus Late Selection Models Main Question: Where in the cognitive process does attentional selection occur? Early? Late? In between? ♦ Some kinds of tasks provide evidence for early selection. ♦ Other tasks provide evidence for late selection. ♦ There is evidence that early selection occurs with hard tasks; Late selection occurs with easy tasks. ♦ (Remember the issue in early versus late selection is the question whether attentional selection occurs before or after the assignment of meanings to stimuli.) Results suggest that we can treat attention like it is a divisible cognitive resource. Comment re virtual reality games and reduction in pain sensations. Define Overt & Covert Spatial Attention

4. Overt Attention & Covert Attention Overt visual attention - controlling visual information acquisition with eye movements and movements of the head and body. Covert visual attention - controlling visual information acquisition without changing the direction of the gaze. Spatial attention is attention to different locations in visual space. ♦ Overt spatial attention - attention to locations is achieved through eye movements, and head and body movements. ♦ Covert spatial attention - a person can shift attention to different locations in the visual field without moving the eyes. Psych 355, Miyamoto, Spr '15 4 Spatial Attention - What Is It?

5. █ + ▲ Fixation Point It is possible to attend to either the red rectangle or the blue triangle while maintaining eye fixation at the +. Covert spatial attention is attention to different locations in visual space without changing the direction of gaze. Psych 355, Miyamoto, Spr '15 5 Covert Spatial Attention Monkey Experiment - Neuropsych Evidence for Spatial Attention

6. Monkey Attention Experiment (Colby, Duhamel, Goldberg, 1995) BOTH CONDITIONS: Monkey holds down a bar while fixating the fixation point. Monkey is rewarded if he releases the bar at the “right” moment. FIXATION ONLY CONDITION: When the fixation point dims, the monkey must release the bar. FIXATION & PERIPHERAL ATTENTION CONDITION: When the peripheral stimulus dims, the monkey must release the bar. Psych 355, Miyamoto, Spr '15 6 Fixation Point Peripheral Stimulus Single-Cell Recording in Monkey Parietal Cortex

7. Psych 355, Miyamoto, Spr '15 7 FIXATION ONLY Recording is made during the period while monkey is waiting for the signal to respond. o The stimulus is the same for the left & right graph, but the monkey is attending to the peripheral location on the right. The cell is more active when the monkey is attending to the peripheral location than when the monkey is attending to the fixation point. Firing Rate FIXATION & PERIPHERAL ATTENTION Unilateral Neglect & Spatial Attention

8. Single-Cell Recording in Monkey Parietal Cortex Psych 355, Miyamoto, Spr '15 8 FIXATION ONLY Results provide neuropsychological evidence for covert spatial attention (attention to the location of the peripheral stimulus). Behavioral evidence for covert spatial attention is provided by experiments with precueing (target stimulus is preceded by a cue that indicates location of target stimulus). o Covert spatial attention is demonstrated by the superior performance when the precue is valid than when it is invalid. See Posner study on pp. 99-100 of Goldstein's textbook. Firing Rate FIXATION & PERIPHERAL ATTENTION Unilateral Neglect & Spatial Attention

9. Unilateral Neglect – A Pathology of Spatial Attention Psych 355, Miyamoto, Spr '15 9 This slide is based on instructional material that was downloaded from the Pearson Publishers website (http://vig.prenhall.com) for Smith & Kosslyn (2006; ISBN 9780131825086). The patient’s copy in the right column neglects the left side of the visual field (opposite to the side of brain damage). Brain Diagram - Locate Parietal Lobe Unilateral Neglect: A deficit of attention in which one entire half of a visual scene is simply ignored. (Discussed in Goldstein Chapter 10) The cause of unilateral neglect is often a stroke that has interrupted the flow of blood to the right parietal lobe. Figure to the right: Patient’s copy of an image (model) shows systematic deficits.

10. Left Hemisphere: Note Location of Parietal Cortex Psych 355, Miyamoto, Spr '15 10 Unilateral neglect is associated with injury to the left or right parietal cortex. Head is facing LEFT Behavioral Differences Between Left & Right Parietal Injuries

11. Psych 355, Miyamoto, Spr '15 More Examples of Unilateral Neglect a)Brain scan of patient showing right parietal damage (head faces up) b)Drawings made by patient. c)Patient instructed to put a crossing line through every line. Large Diagram of the Lobes of the Brain 11

12. Psych 355, Miyamoto, Spr '15 12 Right versus Left Parietal Injury Right: Figure 3.16 from Anderson (2005). Patients with left or right parietal injuries were asked to copy the figure in column A. Right injury: Small parts were correct – general form was not. Left injury: General form was correct – small parts were not.. A: Model to be Copied B: Right Parietal Injury C: Left Parietal Injury Same Slide With Red Emphasis Rectangles On Each Row of Drawings

13. Psych 355, Miyamoto, Spr '15 13 Right versus Left Parietal Injury Right: Figure 3.16 from Anderson (2005). Patients with left or right parietal injuries were asked to copy the figure in column A. Right injury: Small parts were correct – general form was not. Left injury: General form was correct – small parts were not. A: Model to be Copied B: Right Parietal Injury C: Left Parietal Injury Same Slide Without the Red Emphasis Rectangles

14. Psych 355, Miyamoto, Spr '15 14 Left versus Right Parietal Injury Right: Figure 3.16 from Anderson (2005). Patients with left or right parietal injuries were asked to copy the figure in column A. Right injury: Small parts were correct – general form was not. Left injury: General form was correct – small parts were not. A: Model to be Copied B: Right Parietal Injury C: Left Parietal Injury Summary So Far

15. Other Examples of Unilateral Neglect Reported examples: ♦ Patient (male) shaves only half of his face. ♦ Patient (female) puts make up on only half of her face. ♦ Patient only eats food on half of her plate. Bisiach & Luzzatti (1978) tested Italian man with left unilateral neglect. ♦ If asked to describe a current scene, the man fails to describe what is on the left side of the scene. ♦ If asked to describe a familiar place from memory from the perspective of a particular position, he fails to describe what can be seen on the left from that position. Psych 355, Miyamoto, Spr '15 15 Is Unilateral Neglect a Pathology of Spatial Attention? Unilateral (unilateral) neglect is not discussed in the Goldstein's attention chapter (Ch 4); it is briefly discussed in the mental imagery chapter (ch 10, p. 288).

16. Psych 355, Miyamoto, Spr '15 16 Is Unilateral Neglect a Pathology of Spatial Attention? Unilateral neglect (unilateral neglect) seems to involve a problem focusing on particular spatial locations (relative to the viewpoint of an individual). Is visual attention equivalent to attention to locations? Results from object based attention show that the answer it “NO”! Location-Based Attention vs Object-Based Attention – What Are They?

17. Psych 355, Miyamoto, Spr '15 17 Location-Based versus Object-Based Attention Attention is location-based when it is organized around spatial locations in the visual field. Attention is object-based when it is organized around the structure of objects rather than spatial locations. Location-based Spotlight Metaphor Same Slide without the Red Emphasis Rectangles

18. Psych 355, Miyamoto, Spr '15 18 Location-Based versus Object-Based Attention Attention is location-based when it is organized around spatial locations in the visual field. Attention is object-based when it is organized around the structure of objects rather than spatial locations. Location-based Spotlight Metaphor Experimental Demonstration of Object-Based Attention

19. o o o o Psych 355, Miyamoto, Spr '15 19 Demonstration of Object-Based Attention Egly, R., Driver, J., & Rafal, R. D. (1994). Targets can appear at any of the 4 ends of the rectangles. Cue appears at the location where the target is most likely to appear. The RT is fastest at the location of the cue (no surprise), but it is faster at the other location within the object than at an equally close location on a different object. Same Slide Without the Emphasis Ovals +

20. o o o o Psych 355, Miyamoto, Spr '15 20 Demonstration of Object-Based Attention Egly, R., Driver, J., & Rafal, R. D. (1994). Targets can appear at any of the 4 ends of the rectangles. Cue appears at the location where the target is most likely to appear. The RT is fastest at the location of the cue (no surprise), but it is faster at the other location within the object than at an equally close location on a different object. Horizontal Occlusion Does Not Affect Object-Based Effect +

21. Psych 355, Miyamoto, Spr '15 21 Occluding Part of the Object Does Not Affect Object-Based Effect Same finding occurs even if a horizontal bar occludes (hides part of) the vertical “objects.” The greater speed at shifting within an object is not due to the avoidance of object boundaries! Tipper & Behrman - Unilateral Neglect & Object-Based Attention A B C Altered Display o o o o + Standard Display

22. Psych 355, Miyamoto, Spr '15 22 Object-Based Attention & Unilateral Neglect Person with left unilateral neglect (right parietal injury) seems to suffer from a deficit to spatial attention. This is not exactly true!!! Next: How unilateral neglect interacts with object-based attention. Tipper & Behrman Study Object-based attention is discussed in the Goldstein textbook; see Goldstein p. 100 and Item 7 on p. 115. But the relationship between object-based attention and unilateral neglect is not discussed.

23. Psych 355, Miyamoto, Spr '15 23 Response to stimulus is slow. Object-Based Visual Attention & Unilateral Neglect Tipper & Behrman (1996) Patient had left unilateral neglect. Initial display – patient is slower to respond to flash in left circle than to flash in right circle. Response to stimulus is fast. Same Slide without the Sequencing

24. Psych 355, Miyamoto, Spr '15 24 Response to stimulus is slow. Object-Based Visual Attention & Unilateral Neglect Tipper & Behrman (1996) Patient had left unilateral neglect. Initial display – patient is slower to respond to flash in left circle than to flash in right circle. (I added the color and bars in the circles to these displays to make it easier to explain the experiment – they were not used in the actual experiment.) Response to stimulus is fast. Demonstrate Flip Trials

25. Flip Trials Stimulus is presented like this at the beginning of a trial. The stimulus rotates 180 degrees while the patient watches. Psych 355, Miyamoto, Spr '15 25 Repeat This Slide With Label for Pre- & Post Left & Right

26. Psych 355, Miyamoto, Spr '15 26 Flip Trials This circle started on the RIGHT side. Now it’s on the LEFT side. This circle started on the LEFT side. Now it’s on the RIGHT side. How Does Flip Affect Patient’s RT to Target? Stimulus is presented like this at the beginning of a trial. The stimulus rotates 180 degrees while the patient watches.

27. Psych 355, Miyamoto, Spr '15 27 Effect of Rotation on Patient’s RT to Target In general, the patient is slow to respond to information on the “left” side, but........ neglect of the "left side" was defined in terms of the object as it was initially presented, not the current visual stimulation. Object-based attention! AFTER the stimulus rotates: Patient is faster here. Patient is slower here. BEFORE the stimulus rotates: Patient is slower here. Patient is faster here. “No Bar” Condition – An Important Control Condition

28. Psych 355, Miyamoto, Spr '15 28 Important Aspect of the Effect of Flipping the Object If the two circles are not connected by a bar, then flipping the circles has no effect, i.e.,... the patient continues to show inferior performance with a flash on the left. Standard Version with Bar Alternate Version NO Bar Flip Trials in the “No Bar” Condition

29. Flip Trials – No Bar Condition Stimulus is presented like this at the beginning of a trial. As before, the stimulus flips left to right and right to left while the patient watches. Psych 355, Miyamoto, Spr '15 29 Results for "No" Bar Condition

30. Psych 355, Miyamoto, Spr '15 30 Results in “No Bar” Condition Conclusion: For patient with left unilateral neglect, flipping the colored circles only reverses the side with a faster response if the two circles appear to be part of a single object. AFTER the stimulus rotates: Patient is faster here. Patient is slower here. BEFORE the stimulus rotates: Patient is slower here. Patient is faster here. Summary re Object-Base Attention

31. Psych 355, Miyamoto, Spr '15 31 Summary: Object-Based Attention Spatial Attention: Attention is directed to specific locations in the visual field. (a.k.a. location-based attention) Object-Based Attention: Attention is organized around the structure of objects. ♦ Easier to move attention within an object than between objects. ♦ Objects have a special status in attention and perception. Spatial attention and object-based attention are two aspects of human attention. Unilateral neglect exhibits deficits in both spatial attention and object-based attention. Feature Integration Theory