1. Unilateral Neglect, Spatial Attention, Object-Based Attention
Psychology 355: Cognitive Psychology Instructor: John Miyamoto 04/11/2018: Lecture 03-3
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2. Outline Unilateral Neglect (a.k.a., hemispatial neglect)
Object-based attention
Unilateral neglect is a pathology of both spatial attention and of object-based attention.
Psych 355,, Miyamoto, Spr '18

3. Unilateral Neglect – A Pathology of Attention
Unilateral Neglect: A deficit of attention in which one entire half of a visual scene is simply ignored. (Discussed in Goldstein Chapter 10)
(Unilateral Neglect = Hemispatial Neglect)
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.
This slide is based on instructional material that was downloaded from the Pearson Publishers website ( for Smith & Kosslyn (2006; ISBN ).
The patient’s copy in the right column neglects the left side of the visual field (opposite to the side of brain damage).
Psych 355, Miyamoto, Spr '18
Brain Diagram - Locate Parietal Lobe

4. Left Hemisphere: Note Location of Parietal Cortex
Head is facing LEFT
Unilateral neglect is associated with injury to the left or right parietal cortex.
Psych 355, Miyamoto, Spr '18
More Examples of Unilateral Neglect

5. More Examples of Unilateral Neglect
Brain scan of patient showing right parietal damage (head faces up)
Drawings made by patient.
Patient instructed to put a crossing line through every line.
Psych 355, Miyamoto, Spr '18
Behavioral Differences Between Left & Right Parietal Injuries

6. 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
Psych 355, Miyamoto, Spr '18
Same Slide With Red Emphasis Rectangles On Each Row of Drawings

7. 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.
Illustrates specialization in the left and right parietal lobe for particular aspects of attention.
A: Model to be Copied
B: Right Parietal Injury
C: Left Parietal Injury
Psych 355, Miyamoto, Spr '18
Same Slide Without the Red Emphasis Rectangles

8. 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.
Illustrates specialization in the left and right parietal lobe for particular aspects of attention.
A: Model to be Copied
B: Right Parietal Injury
C: Left Parietal Injury
Psych 355, Miyamoto, Spr '18
Is Unilateral Neglect a Pathology of Attention to Locations in the Visual Environment?

9. Is Unilateral Neglect a Pathology of Spatial Attention?
Unilateral neglect (unilateral neglect) involves a problem focusing on particular parts of the spatial environment (relative to the viewpoint of an individual).
Is visual attention equivalent to attention to locations?
Results from object based attention show that the answer is “NO”!
Psych 355, Miyamoto, Spr '18
Location-Based Attention vs Object-Based Attention – What Are They?

10. 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
Psych 355, Miyamoto, Spr '18
Same Slide without the Red Emphasis Rectangles

11. 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
Psych 355, Miyamoto, Spr '18
Experimental Demonstration of Object-Based Attention

12. 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. o +
See 'D:\p355\RCODE\obj-based.attn.exp.Goldstein.ch04.doc' for R-code to make figures similar to the one displayed here.
Psych 355, Miyamoto, Spr '18
Same Slide Without the Emphasis Ovals

13. 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. o +
See 'D:\p355\RCODE\obj-based.attn.exp.Goldstein.ch04.doc' for R-code to make figures similar to the one displayed here.
Horizontal Occlusion Does Not Affect Object-Based Effect
Psych 355, Miyamoto, Spr '18

14. 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!
Standard Display + A B C
Altered Display
Psych 355, Miyamoto, Spr '18
Tipper & Behrman - Unilateral Neglect & Object-Based Attention

15. 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.
Object-based attention is discussed in the Goldstein textbook; see Goldstein p and Item 7 on p But the relationship between object-based attention and unilateral neglect is not discussed.
Psych 355, Miyamoto, Spr '18
Tipper & Behrman Study of Patient with Unilateral Neglect

16. 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 slow.
Response to stimulus is fast.
Psych 355, Miyamoto, Spr '18
Same Slide without the Sequencing

17. 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 slow.
Response to stimulus is fast.
Demonstrate Flip Trials
Psych 355, Miyamoto, Spr '18

18. Flip Trials
Stimulus is presented like this at the beginning of a trial.
The stimulus rotates degrees while the patient watches.
Repeat This Slide With Label for Pre- & Post Left & Right
Psych 355, Miyamoto, Spr '18

19. Stimulus is presented like this at the beginning of a trial.
Flip Trials
Stimulus is presented like this at the beginning of a trial.
The stimulus rotates degrees while the patient watches.
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?
Psych 355, Miyamoto, Spr '18

20. Effect of Rotation on Patient’s RT to Target
BEFORE the stimulus rotates:
AFTER the stimulus rotates:
Patient is slower here.
Patient is faster here.
Patient is faster here.
Patient is slower here.
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!
“No Bar” Condition – An Important Control Condition
Psych 355, Miyamoto, Spr '18

21. 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
Psych 355, Miyamoto, Spr '18

22. 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.
Results for "No" Bar Condition
Psych 355, Miyamoto, Spr '18

23. Results in “No Bar” Condition
BEFORE the stimulus rotates:
AFTER the stimulus rotates:
Patient is slower here.
Patient is slower here.
Patient is faster here.
Patient is faster here.
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.
Summary re Object-Base Attention - END
Psych 355, Miyamoto, Spr '18

24. 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.
Summary So Far: END
Psych 355, Miyamoto, Spr '18

25. Summary So Far
Pathologies of attention demonstrate multiple functional components to attention.
Attention to left or right visual field.
Attention to global perceptual structure versus attention to smaller details
Problems with attention switching – perseveration
Problems with attending to objects (Balint's syndrome)
Is visual attention always equivalent to attention to locations? Results from object based attention show that the answer is “no”! (later)
END
Psych 355, Miyamoto, Spr '18