Attention I failures to select informationWhat is attention?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 and limits on informationExample 2: Fovea demoSlide 6Eye trackingSlide 8Slide 9Slide 10Studies for the improvement of human-computer interfacesDavid Hockney’s photo collage might be a metaphor for the way we see scenesSlide 13Inattentional BlindnessSlide 15Slide 16Slide 17Slide 18Other demosInattentional BlindnessDemo of basketball players(not) noticing person changesSlide 23Failures of Selection in TimeAttentional BlinkSources of LimitationDisorders of Visual AttentionHemispatial NeglectNeglect of the Visual FieldSlide 30Slide 31Visual neglect syndrome can be object-basedSlide 33Simultanagnosic (Balint Syndrome) patients only attend to one object at a timeBalint patients can only attend to one object at a time even if they are overlappingAttention Ifailures to select informationWhat 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 mechanismsAttention enhances some information and inhibits other information. The enhancement enables us to select some information for further processingThe inhibition enables us to set some information aside.AttentionAttention 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 systemsEye 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-trackingEye tracking deviceeye movements during readingEye tracking and Visual AttentionEye tracking and Visual AttentionPainting by Giuseppe Arcimboldo. Earth. c.1570. Oil on wood. Private collection, Vienna, Austria.[Yarbus 1967]Studies for the improvement of human-computer interfacesDavid Hockney’s photo collage might be a metaphor for the way we see scenes1 photo = 1 gazeAttention 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 processingInattentional 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)Some of these demos are from: Simons & Levin, 1997, TINS, 1, 261-267Do you notice the change?a) nob) yesSome of these demos are from: Simons & Levin, 1997, TINS, 1, 261-267Do you notice the change?a) nob) yesSome of these demos are from: Simons & Levin, 1997, TINS, 1, 261-267Do you notice the change?a) nob) yesSome of these demos are from: Simons & Levin, 1997, TINS, 1, 261-267Do you notice the change?a) nob) yesOther demos•Lots of demos:–http://viscog.beckman.uiuc.edu/djs_lab/demos.html–http://dualtask.org/Change_Blindness_Demo/ChangeBlindness.htmlAirplane demoDinner demoInattentional 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).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.phphttp://viscog.beckman.uiuc.edu/flashmovie/25.php(Simons & Chabris, Perception, 1999, 28, 1059 – 1074)Did you notice anything unusual?a) nob) yes(not) noticing person changes Demos from Dan Simons (University of Illinois): http://viscog.beckman.uiuc.edu/change/demolinks.shtml http://viscog.beckman.uiuc.edu/flashmovie/12.phphttp://viscog.beckman.uiuc.edu/flashmovie/10.phpsee also letter task: http://www.dualtask.org/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 objectsFailures of Selection in TimeWhen 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.Attentional BlinkDemos:http://www.cs.kent.ac.uk/people/rpg/pc52/AB_Webscript/instr.htmlhttp://psych.hanover.edu/JavaTest/Cognition/Cognition/attentionalblink_instructions.htmlSources of LimitationThe 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.Disorders of Visual AttentionHemispatial 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 ofPatients 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 FieldNeglect of the Visual FieldDifficulty crossing out itemsDifficulty copying items55 y.o. right handed male R TPJ infarct (Mesulam, 2000)Marshall and