1. Attention I failures to select information

2. What is attention? How is the word used? Examples: –something bright caught my attention –I didn’t see you, I was paying attention to the game –I struggled to pay attention to the lecture –I don’t remember even cleaning the table, I must not have been paying attention Attention refers to many different kinds of mechanisms

3. Attention enhances some information and inhibits other information. The enhancement enables us to select some information for further processing The inhibition enables us to set some information aside. Attention

4. Attention and limits on information We need attention to limit the amount of information that is processed Why are there limits on the amount of information we can process? –limited sensory systems

5. Example 2: Fovea demo

7. Eye tracking Eye-tracking studies can tell us which information is attended to –Our eyes are drawn both by top-down information (e.g. a goal to find specific information) as well as bottom-up information (e.g. a flashing light) Commercial intro on eye-tracking Eye tracking device eye movements during reading

8. Eye tracking and Visual Attention

9. Painting by Giuseppe Arcimboldo. Earth. c.1570. Oil on wood. Private collection, Vienna, Austria.

10. [Yarbus 1967]

11. Studies for the improvement of human-computer interfaces

12. David Hockney’s photo collage might be a metaphor for the way we see scenes 1 photo = 1 gaze

13. Attention and limits on information Human information processing is massively parallel, up to a point where we have serial bottlenecks Bottleneck: a restriction on the amount of information that can be processed at once forcing serial processing

14. Inattentional Blindness After bottleneck, it is the allocation of our attention that determines what is analyzed. Often, we are unable to process information that is unattended. This can lead to inattentional blindness (aka change blindness)

15. Some of these demos are from: Simons & Levin, 1997, TINS, 1, 261-267 Do you notice the change? a)no b)yes

16. Some of these demos are from: Simons & Levin, 1997, TINS, 1, 261-267 Do you notice the change? a)no b)yes

17. Some of these demos are from: Simons & Levin, 1997, TINS, 1, 261-267 Do you notice the change? a)no b)yes

18. Some of these demos are from: Simons & Levin, 1997, TINS, 1, 261-267 Do you notice the change? a)no b)yes

19. Other demos Lots of demos: –http://viscog.beckman.uiuc.edu/djs_lab/demos.htmlhttp://viscog.beckman.uiuc.edu/djs_lab/demos.html –http://dualtask.org/Change_Blindness_Demo/ChangeBlindness.htmlhttp://dualtask.org/Change_Blindness_Demo/ChangeBlindness.html Airplane demo Dinner demo

20. Inattentional Blindness Why is it hard to notice the change (initially)? When motion detection is disrupted, it is very difficult to observe changes to unattended image locations Brain makes reasonable assumption that things do not change unexpectedly (in the absence of motion cues).

21. Demo of basketball players Task: count the number of times the white team passes the ball to each other Important to pay close attention to the white team Demos at: http://viscog.beckman.uiuc.edu/flashmovie/15.php http://viscog.beckman.uiuc.edu/flashmovie/25.php http://viscog.beckman.uiuc.edu/flashmovie/15.php http://viscog.beckman.uiuc.edu/flashmovie/25.php (Simons & Chabris, Perception, 1999, 28, 1059 – 1074) Did you notice anything unusual? a)no b)yes

22. (not) noticing person changes Demos from Dan Simons (University of Illinois): http://viscog.beckman.uiuc.edu/change/demolinks.shtml http://viscog.beckman.uiuc.edu/change/demolinks.shtml http://viscog.beckman.uiuc.edu/flashmovie/12.php http://viscog.beckman.uiuc.edu/flashmovie/10.php see also letter task: http://www.dualtask.org/http://www.dualtask.org/

23. Inattentional Blindness Shows there are remarkable gaps in our perception Human’s interpretation of the visual field is much sparser than the subjective experience of “seeing” suggests Our visual system might be overwhelmed without change blindness -- in a real-world setting with many moving objects, it might make sense to “track” only a few objects

24. Failures of Selection in Time When new information (even if only a small amount) arrives in a rapid stream, spending time processing it will cause you to miss some other incoming information, resulting in what are called failures of selection in time.

25. Attentional Blink Demos: http://www.cs.kent.ac.uk/people/rpg/pc52/AB_Webscript/instr.html http://psych.hanover.edu/JavaTest/Cognition/Cognition/attentionalblink_instructions.html

26. Sources of Limitation The attentional blink is a short period during which incoming information is not registered, similar in effect to the physical blanking out of visual information during the blink of an eye. Divided-attention studies demonstrate that performance is hampered when you have to attend to two separate sources of visual information or two separate visual events. In all these cases, the decrement in performance is referred to as dual-task interference.

27. Disorders of Visual Attention

28. Hemispatial Neglect Cause –often a stroke that has interrupted the flow of blood to the right parietal lobe that is thought to be critical inattention and selection. Symptoms: –Failure to acknowledge objects in the field contralateral to the lesion Often no perceptual deficit –Neglect patients still activate visual regions in occipital lobes that they claim not to be aware of

29. Patients may: fail to dress the left side of their body disclaim “ ownership ” of left limbs not recognize familiar people presented on the left side deny the illness Neglect of the Visual Field

30. Difficulty crossing out items Difficulty copying items 55 y.o. right handed male R TPJ infarct (Mesulam, 2000)

31. Marshall and Halligan, 1993 Patients can neglect the left side of the object, rather than the left side of space. Black lines show expected left-sided person-centred versus red lines showing actual point where the patient neglected Visual neglect syndrome can be object-based Control Neglect patient

32. Visual neglect syndrome can be object-based  Patient with object neglect cannot detect differences on left side of an object even when falling into right side of space Driver and Halligan (1991)

33. Visual neglect syndrome can be object-based When a right neglect patient is shown a dumbbell that rotates, the patient continues to neglect the object that had been on the right, even though it is now on the left (Behrmann & Tipper, 1999).

34. Simultanagnosic (Balint Syndrome) patients only attend to one object at a time Simultanagnosic patients cannot judge the relative length of two lines, but they can tell that a figure made by connecting the ends of the lines is not a rectangle but a trapezoid (Holmes & Horax, 1919).

35. Balint patients can only attend to one object at a time even if they are overlapping Luria, 1959