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Perception, Cognition and the Perception, Cognition and the VisualVisual
Seeing, thinking, knowing Seeing, thinking, knowing (link to optical video)(link to optical video)
Perception: Pre-attentive Perception: Pre-attentive Perceptual/Cognitive issuesPerceptual/Cognitive issues
– How do human visual systems analyzeHow do human visual systems analyzeimages?images? preattentively,without the need for focused attentionpreattentively,without the need for focused attention Generally less than 200-250 msecs (eyeGenerally less than 200-250 msecs (eye
movements take 200 msecs)movements take 200 msecs)
Preattentive ProcessesPreattentive Processes Grid stays while asterix disappearsGrid stays while asterix disappears
How Many threes? How Many threes?
12817687561389765469845069856049828212817687561389765469845069856049828267629809858458224509856458945098450967629809858458224509856458945098450980943585909103020990595959577256467580943585909103020990595959577256467505067890456788457898098216776548763605067890456788457898098216776548763649085609129496864908560912949686
How many threes?How many threes?
12817687561128176875613389765469845069856049828289765469845069856049828267629809858458224509856458945098450967629809858458224509856458945098450980948094335585909108590910330209905959595772564675020990595959577256467505067890456788457898098216776548760506789045678845789809821677654876336649085609129496864908560912949686
Hue: where is the red circle? Hue: where is the red circle? Not Usually Pre-attentiveNot Usually Pre-attentive
Region SearchRegion Search
Hue boundary identifiedpre-attentively
Form variations do NOTinterfere with hueboundary identification
Form boundary NOTidentified pre-attentively
Hue variations interferewith form boundaryidentification
Area EstimationArea Estimation Blue rectangles? Sloped rectangles?Blue rectangles? Sloped rectangles?
Color for Categories and Color for Categories and SequencesSequences
Links to websites about color systemsLinks to websites about color systems CIECIE, , MunsellMunsell
Using Color--Varied Opnions, Using Color--Varied Opnions, More later in the courseMore later in the course
blue in large regions, not thin linesblue in large regions, not thin lines red and green in the center of thered and green in the center of the
field of view (edges of retina not sensitivefield of view (edges of retina not sensitiveto these)to these)
black, white, yellow in peripheryblack, white, yellow in periphery Color BrewerColor Brewer PantonePantone
Perceptual “Tasks”Perceptual “Tasks”
Target detection ( Is something there?)Target detection ( Is something there?) Boundary detection (Can the elements be Boundary detection (Can the elements be
grouped?)grouped?) Counting ( How many elements of a certain Counting ( How many elements of a certain
type aretype arepresent?)present?)
Perceptual PropertiesPerceptual Properties
Luminance (measured) Brightness (perceived)Luminance (measured) Brightness (perceived) Color Color
– sensory response to electromagnetic radiation-- sensory response to electromagnetic radiation-- wavelengths 0.4-0.7 micrometers)wavelengths 0.4-0.7 micrometers)
– Hue, value, saturationHue, value, saturation TextureTexture ShapeShape Sources: Colin Ware & Morgan Kaufmann Sources: Colin Ware & Morgan Kaufmann
Information Visualization--Perception for DesignInformation Visualization--Perception for Design
Optical Illusions and Optical Illusions and Programmed VariationsProgrammed Variations
LinkLink Chernoff Faces Chernoff Faces linklink
Pre-attentive Perception, Pre-attentive Perception, cognition & visualizationcognition & visualization
“Understanding of what is processed pre-attentivelyis probably the most important contribution that vision
science can make to data visualization.”
BUT“Humans do not perceive much unless we haveat least some expectation and need to see it.”
- Colin Ware
Cognitive issuesCognitive issues
Visualization as a tool useful forVisualization as a tool useful for
aiding comprehension and understandingaiding comprehension and understanding Seeing as thinkingSeeing as thinking Visual Cognition & Attention--Visual CognitionVisual Cognition & Attention--Visual Cognition
Lab. U. Illinois Lab. U. Illinois
Visualizations of Home/House. Child Katrina SurvivorsVisualizations of Home/House. Child Katrina Survivors
House?HomeHouse?Home
Sources: Slide show of Katrina victim’s drawings of Sources: Slide show of Katrina victim’s drawings of house/home,house/home, Dewann, S. Dewann, S. “Using Crayons to Exorcise Katrina, “Using Crayons to Exorcise Katrina, New York TimesNew York Times, Monday September 17, , Monday September 17, 2007, Arts Section, B1,5.2007, Arts Section, B1,5.
Graphical visualization to Graphical visualization to support more efficient task support more efficient task performanceperformance
– Allowing substitution of rapid perceptualAllowing substitution of rapid perceptual
influences for difficult logical inferencesinfluences for difficult logical inferences– Reducing search for information required for task Reducing search for information required for task
completioncompletion
(Sometimes text is better, however)(Sometimes text is better, however)
IssuesIssues
Cognitive ArtifactsCognitive Artifacts Matching Representation to TaskMatching Representation to Task Representations Aid Info Access and Representations Aid Info Access and
ComputationComputation Naturalness and Experiential CognitionNaturalness and Experiential Cognition
Cognitive MapsCognitive Maps
You have some existing internal model of theYou have some existing internal model of the
system, stops, how to get theresystem, stops, how to get there– glance at SFU map for helpglance at SFU map for help– Refine your internal model, clarifying items and Refine your internal model, clarifying items and
extending itextending it Note differences between your map & the Note differences between your map & the
official oneofficial one
Process Models: Navigation in Process Models: Navigation in Visual systemsVisual systems
-process by which a person looks at a graphic -process by which a person looks at a graphic and makes some use of itand makes some use of it– substepssubsteps– Can you describe process?Can you describe process?– Navigation in visual systems - Creation and Navigation in visual systems - Creation and
interpretation of an internal mental modelinterpretation of an internal mental model
Information foragingInformation foraging
Search for schema (representation)Search for schema (representation) Problem solve to trade off featuresProblem solve to trade off features Search for a new schema that reducesSearch for a new schema that reduces
problemproblem Package the patterns found in somePackage the patterns found in some
output productoutput product
Browsing useful whenBrowsing useful when
Good underlying structure so that items close to oneGood underlying structure so that items close to oneanother can be inferred to be similaranother can be inferred to be similar
Users are unfamiliar with collection contentsUsers are unfamiliar with collection contents Users have limited understanding of how system isUsers have limited understanding of how system is
organized and prefer less cognitively loaded methodorganized and prefer less cognitively loaded methodof explorationof exploration
Users have difficulty verbalizing underlyingUsers have difficulty verbalizing underlyinginformation needinformation need
Information is easier to recognize than describeInformation is easier to recognize than describe