Chapter3:
AttentioninPerceptionandDisplaySpace
Part2:ParallelProcessingandDividedAttention
(Wickensetal:Ch.3.3,64-83)
(+Ch.2.7,35-40)
CriticalAspectsofAttention(Review)
SelectiveAttentionlModels
•  abilitytoselectperceptualchanneltofocusattentionatanyparticularmoment
–  e.g.visualsampling,targetsearch,etc.
•  influencesdesignofinstrumentlayouts,procedures,searchtasks,training,etc.
DividedAttentionModels
•  abilitytodivideattention“simultaneously”acrosstwoormoreperceptualchannels
–  e.g.displaymonitoring,reading,timesharing,etc.
•  influencesdesignofintegrateddisplays,operatingprocedures,multitasking,etc.
FocusedAttentionModels
•  abilitytofocusonparticularperceptualchannel,andexcludestimulationfromother
(adjacent)channels
•  ≈‘opposite’ofdividedattention
–  e.g.targetsearch,displaymonitoring,studying,problemsolving,translating,etc.
•  influencesdesignofworkenvironments,warningsystems,etc.
SustainedAttentionTasks
•  abilityofhumanstomaintainvigilancelevelsoverlongperiodsoftime
•  influencesdesignofworkenvironments,displayinterfaces,etc.
ExampleofLowLevelPre-attentive
Processing(Review)
“Find Large T”
versus
"Find Red S”
or
“Find X or K”
• letterS“popsout”automatically...becauseitisred,whileothersaren’t
• doesn’tneedtoinvokeconsciousattentionalprocessesèparallelsearch
• (searchforXorKinvolvesone(diagonal)feature)
Figure-GroundPhenomenon
Faces?
orVase?
SaxophonePlayer?
orWoman?
YoungWoman?
orOldWoman?
Somelesswellknownexamples
OldMan?
orYoungCouple?
Whichbuildingisinfront?
Wickens’InformationProcessingModel
Pre-attentive
Cognitive
•  separationofpre-attentiveandcognitiveperception
•  notallperceptionisbottom-up(basedonelementsofretinalimages)
•  semanticcuingcaninfluenceperception,inatop-downmanner
HolisticInformationProcessing
•  Whenwholeisperceiveddirectly,ratherthanasaconsequence
ofseparateanalysisofconstituentelements.
•  Complexityofconstituentelementsdoesnotaffecttimerequired
toprocessstimuliholistically...butdoesaffectthetimerequired
foranalyticprocessing
•  Objectsperceivedasintegralwhole,dependingon:
–  surroundingcontours
–  correlatedattributes
–  familiarity
AWell-knownExample
CanyouseetheDalmatian?
DynamicDemosofHolisticProcessing
GlobalversusLocalProcessing
•  Global/HolisticProcessing
–  Organises(visual)worldintoobjects,groups,
patterns,etc.
–  Automatic/Pre-attentive
–  ExhibitsGlobalPrecedence
versus
•  Localprocessing
–  Separateprocessingofindividualobjectsindisplay
–  Dependsonmorefocusedselectiveattention
GlobalvsLocalProcessingExample
T T
T T T
T T T T T
T
T T TT T
T
T T
T
T T T
*^&#&+%$$@*#
$
*
&
&
$
^
#
%
“LargeLetter”=T
&
(
#
0
“SmallLetter”=T
Inthefollowingslide,replytoquestion“WhatistheSmallLetter”or“WhatistheLargeLetter”
GlobalvsLocalProcessingExample
TTTTTTT
T
T
T
T
T
TTTTT
T
T
T
T
T
T
FFFFFFF
F
F
F
F
F
FFFFF
F
F
F
F
F
F
TTTTTTT
T
T
T
T
T
TTTTT
T
T
T
T
T
T
FFFFFFF
F
F
F
F
F
FFFFF
F
F
F
F
F
F
Whatrelativeresultsshouldwehaveobserved(ifexperimentdoneproperly)?
WhatistheSMALL
Letter?
WhatistheSMALL
Letter?
WhatistheLARGE
Letter?
WhatistheLARGE
Letter?
Slowest/
LeastAccurate
SecondinSpeed
&Accuracy?
ThirdinSpeed
&Accuracy?
Fastest/
MostAccurate
GlobalvsLocalProcessingExample
Which‘groups’oflettersaremoresimilartoeachother?
L L
L
L
L
L
T
L T T
L
L T
T
T
T
T
T
T
T
T
T T
T
L L
T
T T
T
L
L L
L L
L
T T
T
T T
L L
L L
T T
T T
T
L
L
T
T
T
T
T
LessSimilarity
T
T
T
T
T
T T
T
T
GreaterSimilarity
LT
TT
Textons:
Fundamental
ElementsinPreattentiveVision
andPerception
ofTextures
(Julesz,1983)
a)Texturepairdefinedby
presenceorabsenceof
crossinglinesegments.
b)Texturepairsduetogap
differenceinL-shaped
elementsindistinguishable.
c)T-andL-shapedelements
indistinguishable.Endofline
terminatornotadequatefor
distinguishingtexture.
d)Linecrossingatmid-point
orendoflinesinsufficient
fordistinguishingtexture.
Canweapplytheseprinciplesofpre-attentiveprocessing
tothedesignofcomplexhuman-machineinterfaces?
Inotherwords,howcandisplaydesigners
exploitmodelsofperceptualorganisation
andpre-attentiveprocessing?
•  Goals:
–  tosupportparallelprocessing(dividedattention)
whenappropriate
–  tosuppressparallelprocessing(andsupportfocussed
attention)whenappropriate
•  PrinciplesofSpatialProximity
•  PrinciplesofObject-BasedProximity
•  ProximityCompatibilityPrinciple
producing partial masking. Minimal separation is more likely with miniaturized hand-held
displays, or with display overlay, as found with head-up displays or database overlays (Kroft
& Wickens, 2003; Beck et al., 2010). Numerosity and readout clutter have been referred to
as global density and local density clutter, respectively (Tullis, 1988; see also Beck et al.,
2010; Wickens, Vincow, et al., 1997).
• Disorganizational clutter describes the random location of distractors in search fields that
are not “structured.” Examples of structured and unstructured search fields are shown in
the left and right panels respectively, of Figure 3.3.
Unstructuredlayoutperceivedas(disorganisational)clutter
• Heterogeneous clutter refers to the heterogeneity of the non-target background features
=>requireslocalprocessing
(like color, shape or size) which we saw above was an impediment to visual search.
StructuredvsUnstructuredSearchFields
•
these clutter factors are manifest in the use of maps, whose design we discuss in more detail
•  All
Organised/structuredlayoutfacilitatesglobalprocessing
in Chapter 5. Various researchers have quantified either individual factors (Yeh & Wickens, 2001)
or developed metrics that combine the factors (Beck, Lohrenz, & Trafton, 2010; Rosenholtz,
(a)
(b)
FIGURE 3.3 (a) Structured Gestalt principles of display organization. (b) Unstructured search field.
EmergentFeatures.
•
•
•
•
Emergentfeaturesarerelatedtoglobalprocessingconcept
Relatedtoaggregationofstimuli;notevidentineachitemonitsown
Facilitatespre-attentive(rapid)processing
Shouldbecompatiblewithtask
Chapter 3 • Attention in Perception and Display Space
(a)
65
(b)
FIGURE 3.4 Local (a) and global (b) perception in aircraft engine dials. Determining whether the pointer
indicates a normal position in (a) requires separate examination of each dial. In (b) the dials have been rotated so that the normal state is straight up. This arrangement means that each column of pointers creates
an emergent feature (a series of vertical lines). Deviation from the vertical is easy to detect with this arrangement. The arrows indicate the mapping of display column to aircraft engine (discussed further in text).
will discuss such spatial display compatibility further in Chapter 4. Banbury, Selcon, and McCrerie
(NB:Considerengineparameterdisplayarrangement:{Column1&3forLeftengine;Column2&4forrightengine}
(1997) found a four-fold increase in check-reading errors for this type of engine panel arrangeIsthiscompatiblewiththephysicalsystem?)
ment, compared to a redesigned panel which grouped both the primary and the secondary left
engine dials on the left side, and the right engine dials on the right side. We will touch upon principles relating to the compatibility between display and task requirements later on in this chapter.
Howcandisplaydesignersexploitmodelsof
perceptualorganisationandpre-attentiveprocessing?
•  Goals:
–  tosupportparallelprocessing(dividedattention)
whenappropriate
–  tosuppressparallelprocessing(andsupportfocussed
attention)whenappropriate
•  PrinciplesofSpatialProximity
•  PrinciplesofObject-BasedProximity
•  ProximityCompatibilityPrinciple
SpatialProximity
•  Placingvisualinformationsourcesclosetogether(withinUFOV),
withexpectationthatparallelprocessingwillbesupported
withinforwardfieldofview(FFOV)
•  AugmentedReality(AR)Displayssuperimposecomputer
generatedimagesontoreal-worldscenes,forexample:
–  WindowmountedHead-upDisplays(HUDs),
–  HMDs:Head(orspectacle)mounteddisplays(e.g.GoogleGlass)
–  Hand-heldARdisplays(egPokemonGo)
Principle:bysuperimposingtask-related
informationonviewofoutsideworld,
bothcanbeattendedtoinparallel,due
to:
•  reducedscanningtransitiontimes
(recallSEEVmodel)
•  reducedvisualaccommodationtime
andeffort
•  reducedlight-darkadaptation
HUDAugmentedRealityintheAutomobile
AudiNightViewAssist
head-down configuration. The airplane can be seen, poised to “move out,” in Figure 3.5b. As we
saw earlier, placing information sources together does not necessarily gurarantee that both will
be processed (remember inattentional blindness and the gorilla and the basketball players). This
apparent contradiction hinges on the expectations of the observer. We are likely to see advantages to the HUD format when the observer expects the events in the superimposed background;
that is, when they are likely to occur (high expectancy). However, the HUD format will impair
Head-upDisplaysandForwardFieldofView
NB:Noteprincipleof
ConformalSymbology:
•Correspondenceof
objectsacrossviews
•Createsnew“shared
object”
(a)
(b)
(c)
FIGURE 3.5 (a) Head up display (HUD) used in aviation. (b) Head up display with conformal imagery.
Note the airplane on the ground by the runway. (c) Head up display with conformal imagery (runway
overlay). Source: (3.5a) Richard Baker/Corbis.
However…bewareofinattentionblindness
Conformalimagery(good)……however…….potentialinattentiontootheraircraft!!
Spatialproximitycancauseproblems(failuresofdividedattention)whenstimuliunexpected.
HelicopterHUDExample
Howcandisplaydesignersexploitmodelsof
perceptualorganisationandpre-attentiveprocessing?
•  Goals:
–  tosupportparallelprocessing(dividedattention)
whenappropriate
–  tosuppressparallelprocessing(andsupportfocussed
attention)whenappropriate
•  PrinciplesofSpatialProximity
•  PrinciplesofObject-BasedProximity
•  ProximityCompatibilityPrinciple
SpatiallyproximalHead-upDisplayssupportparallelprocessing.
Whataboutsuppressingparallelprocessing?
SomeProblemswithspatialproximity
•  Absenceof(orinsufficient)conformality
•  Spatialseparationindepth:
–  co-locatedstimulimayappearatdifferentdepthplanes
(e.g.usingstereoscopicdisplays)
•  Co-locatedstimulinotimmunetochangeblindness
•  Perceptualcompetition
•  Responseconflicts
ResponseConflictsduetoSpatialProximity
Eriksen&Eriksen(1974)
http://cognitivefun.net/test/6
EriksenFlankerTest:Somesamplestimuli
“Pressthe<or>keyasquicklyaspossible,accordingtothedirectionofthecentralarrow.”
http://cognitivefun.net/test/6
ResponseConflictsduetoSpatialProximity
Eriksen&Eriksen(1974)
Twotargets,ForH:
H(PressRightbutton)
(PressLeftButton)F
Control:
RedundancyGain:
H
PerceptualCompetition:
KHK
HHH
ResponseConflict:
FHF
ImplicationsofResponseConflictsduetoSpatialProximity
(Eriksen&Eriksen,1974)
•  PerceptualCompetition(KHK)
–  Increaseddisplayclutterleadstofailuretofocusbetween
relevantandirrelevantèRTincreases
•  Responseconflict(FHF)versusRedundancygain(HHH)
–  Proximityallowstwochannelstobeprocessedinparallel…
evenifundesired
–  Whentherearedifferentimplicationsforaction,sourcesof
informationcancompeteattheperceptuallevel
–  Iftheydisagree,canleadtoresponseconflict:
•  RTincreasesand/orprobabilityoferrorincreases
–  Iftheyagree,canleadtoredundancygain:
•  RTdecreasesand/orprobabilityoferrordecreases
(RT:ResponseTime)
FailuresofSpatialProximity
StroopEffectDemo(ppt)
StroopEffectSummary
•  Whathappenswhendifferentinformationchannelscomprise
differentdimensionsofthesamephysicalstimulus?
–  e.g.colour,shape,location,size,etc.
•  MostcommonformofStrooptask:“Nameinkcolour”
XXXXXXXX
GREENRED
•  Ingeneral:
–  RTand/orerrorrateincreasewhencolournameandink
colourconflict(relativetoneutralcontrol),
•  i.e.responseconflict
–  Redundancygaincanalsooccur,wheninkcolourand
colournamecoincide(èreducedRTand/orerrorrate)
McGurkEffect:AnotherFailureofSpatialProximity
McGurkEffectDemo
http://www.moillusions.com/2011/05/mcgurk-effect-audio-video-illusion.html
(3min)
Howcandisplaydesignersexploitmodelsof
perceptualorganisationandpre-attentiveprocessing?
•  Goals:
–  tosupportparallelprocessing(dividedattention)
whenappropriate
–  tosuppressparallelprocessing(andsupportfocussed
attention)whenappropriate
•  PrinciplesofSpatialProximity
•  PrinciplesofObject-BasedProximity
•  ProximityCompatibilityPrinciple
Object-BasedProximity
•  Similaritycanbebasedonmorethanspatialproximity
•  ObjectFiletheoryofattention:
–  objectfeaturesperceivedinearlystage,&thencombinedlater
–  perceptualprocessingisparallelwithinthefeaturesofasingle
object,butserialacrossdifferentobjects
•  Inotherwords,organisingfeatures(includingemergent
features)ofmultipledisplayeditemscanresultin
perceptionofintegralobjects
–  e.g.conformalsymbology
–  e.g.objectdisplays
https://en.wikipedia.org/wiki/Feature_integration_theory
Canweapplyobjectbasedproximityprincipletodesign
displaysforcomplex,multi-degree-of-freedomsystems?
70
Chapter 3 • Attention in Perception and Display Space
CORE EXIT
579/422°F
0 SUBCOOL
WID RCS PRESS
1265/2235 PSIG
768 MCP
Examples/Applicationsof
Object-BasedDisplays
STARTUP
0 0 DPM
PRZR LEV
0/41%
CNTMT PRESS
15 PSIG
RV LEV
70%
RAD CNTMT
SEC
OTHER
WID SG LEV lp 2
39/50%
(a)
Ventilator
Patient
Volume
Dead
space
Alveolar
space
Rate
1
2
3
4
5
7
8
9
10
11
6
(b)
159
PVR
1363
SVR
2394
SVR
159
PVR
100
SaO2
4
CVP
30/10
18
PAP
8
LAP
HR 72
SV 70
CO 5.0
120/80
90
MAP
92
SaO2
2
CVP
25/5
12
PAP
9
LAP
HR 103
SV 34
CO 3.5
70/40
50
MAP
(c)
Wickensetal,Fig.3.7
FIGURE 3.7 Examples of object displays. (a) safety parameter display, (b) medical display of oxygen exchange,
(c) graphical cardiovascular display for anesthesia. Source: Human Factors: The journal of the Human Factors
Society by Human Factors Society; Human Factors Society of America. Reproduced with permission of Human
Factors and Ergonomics Society in the format republish in a book/journal via Copyright Clearance Center.
The object display concept can be applied to text as well. When a graphic designer places
text on a display, there are various techniques for ensuring that its content is associated with the
object it identifies (e.g., spatial proximity, arrows, similar colors,). The ultimate method for ensuring association between elements is achieved by making multiple elements part of the same
PolygonSafetyParameterDisplay(Westinghouse)
•  Connectspokestoformpolygon
•  Assumingparallelprocessing(dividedattention)required,
integratesseveralinformationsourcesintoonedisplay
•  Takesadvantageofobjectbasedproximity
•  Emergentfeatures–propertyofwholeshape,notseen
whenpartsinisolation
Example:GraphicalCardiovascularDisplay
(Drews&Westenskow,2006)
Traditionaldisplayinanaesthesiology:
Single-Sensor,Single-Indicator(SSSI)
‘GraphicalPolygonDisplay’
Example:GraphicalCardiovascularDisplay
(Drews&Westenskow,2006)
(a)
-  Showingnormalstate,withsymmetry
-  Incorporatesclinician’smentalmodel
(b)
-  Showingmyocardialischemia
-  Asymmetriesshowchangesinvolumestatus(a),
withhighpreloadandlowafterload
-  emergentfeatureofcrinkledheart(b)with
reductioninsizeofleftheart;reducedcardiac
output
CVP=CentralVenousPressure;PAP=PulmonaryArteryPressure;PVR=PulmonaryvascularResistance;
LAP=LeftArterialPressure;CO=CardiacOutput;SV=StrokeVolume;MAP=MeanArterialPressure;
SVR=SystemicVascularResistance;SaO2=BloodOxygenSaturation;ST=SegmentDepression.
Example:GraphicalCardiovascularDisplay
(Drews&Westenskow,2006)
NormalState
Hypovolemia:abnormaldecreasein
volumeofbloodcirculatinginbody
Bradycardia:abnormaldecreaseheartrate
CVP=CentralVenousPressure;PAP=PulmonaryArteryPressure;PVR=PulmonaryvascularResistance;
LAP=LeftArterialPressure;CO=CardiacOutput;SV=StrokeVolume;MAP=MeanArterialPressure;
SVR=SystemicVascularResistance;SaO2=BloodOxygenSaturation;ST=SegmentDepression.
AnotherExampleofIntegratedObjectDisplay
Chapter 3 • Attention in Perception and Display Space
FIGURE 3.8
Axis Maps.
Words as streets: an integrated object display. Source: “Chicago Typographic Map” by
We are beginning to see a pattern here: there is a relationship between the choice of a display
representation and a particular set of task demands (what we might call a task representation; Smith,
71
Review(fromChapter2):
OrthogonalvsCorrelatedDimensionsofSource
•  OrthogonalDimensions
–  wheninformationpresentedalonganydimensionis
independentofinformationpresentedalongother
dimensions
–  maximisespotential‘efficiency’oftransmission
•  CorrelatedDimensions
–  whenlevelofinformationinonedimensionconstrains
amountofinformationavailablealongotherdimensions
(i.e.redundancy)
–  maximisesreliabilityoftransmission
•  BotharePropertiesofInformationSource
–  (i.e.theydonotcharacteriseinformationtransmission)
(FromChapter2)
PhysicalFormofPresentation(Stimulus):
SeparablevsIntegralDimensions
SeparableDimensions
•  whenlevelofinformationalonganyonedimensioncanbe
transmittedwithoutspecifyinglevelsalonganotherdimension
•  eachdimensionperceivedasindependentofotherdimensions
•  i.e.it’seasytofocusononedimensionandignoretheother
•  e.g.colourandfilltexture
•  e.g.perpendicularvectors
(FromChapter2)
PhysicalFormofStimuli:
SeparablevsIntegralDimensions
IntegralDimensions
•  whenlevelofinformationalongeachdimensioninfluences
perceptionoflevelsalongotherdimensions
•  dimensionsareperceivedasbeingdependent
•  inotherwords,it’sdifficulttoignoreotherdimensionsandfocuson
justonedimension
•  e.g.colourandbrightnessofanbject
•  e.g.rectangleheightandwidth
SourceInformationvsPhysicalForm
PHYSICALFORM(DISPLAY)DIMENSIONS
SEPARABLE
DIMENSIONS
ORTHOGONAL
DIMENSIONS
SOURCE
DIMENSIONS
CORRELATED
DIMENSIONS
INTEGRAL
DIMENSIONS
western_railway_train_time_table_down.gif (GIF Image, 665×901 pixels)...
Correlated
Information
EncodedSeparably
(moreorless)
•
•
•
•
MumbaiWesternRailwayTimetable
Eachentryisseparatedeparturetime
Someredundancy:downwards=later
Butnocommunicationofspeed,
direction,relativetimes,etc.
http://binishphilip.files.wordpress.com/2009/02/western_railway
RailTimetablewithIntegralDimensions
(byE.J.Marey,1880’s,copiedfromEdwardTufte:TheVisualDisplayofQuantitativeInformation)
AnotherReal-WorldExample:AnaesthesiaMachine
Exercise:
•  Aretheinformation
sourceshereorthogonal
orcorrelated?
•  Arethedisplayshere
separableorintegral?
DesignImplications
•  Ifdata(source)dimensionsarecorrelated,itis
generallybettertouseintegraldisplaydimensions
–  (Lateron,we’lltalkaboutconfiguraldisplays)
•  Ifdata(source)dimensionsareorthogonal,itis
generallybettertouseseparabledisplaydimensions
–  Unidimensionaljudgmentcanbeimpairedbyintegral
displaysofseparabledimensions
•  Isthereunderlyingcorrelationbetweenvariables?
–  Ifso,integraldimensionsmayhelp
–  e.g.altitude+temperature
–  e.g.tidallungvolume+respiratoryrate
Example:ObjectDisplayofRespiratoryFunctioning
[Breaths/minute]*[volume/breath]=>[volume/minute]=Areaofrectangle
RevisitStroopEffect
•  Whathappenswhendifferentinformationchannelscomprise
differentdimensionsofthesamephysicalstimulus?
–  e.g.colour,shape,location,size,etc.
•  MostcommonformofStrooptask:“Nameinkcolour”
XXXXXXXX
GREENRED
•  Ingeneral:
–  RTand/orerrorrateincreasewhencolournameandink
colourconflict(relativetoneutralcontrol)
•  Thisisanexampleoforthogonalsourcedimensions
presentedasadisplaywithintegraldimensions
–  Redundancygaincanalsooccur,wheninkcolourand
colournamecoincide(èreducedRTand/orerrorrate)
•  Thisisanexampleofcorrelatedsourcedimensions
presentedasadisplaywithintegraldimensions
Pairsof(generallyaccepted)Integral&Separable
Dimensions(Table2.2)
Integral Dimensions
Separable Dimensions
HeightofRectangle
WidthofRectangle
VerticalPosition
HorizontalPosition
Lightness
ColourSaturation
Size(Area)
ColourSaturation
Hue
ColourSaturation
Size(Area)
Brightness
Pitch
Timbre
Shape
ColourSaturation
Pitch
Loudness
Shape(LetterShape) Colour
Timbre:Pitch
Location
Duration
Location
FacialFeatures
SpacingofFeatures
Orientation(angle)
Size
SpatialLocation
TemporalOrder
a display and the task requirements. This is illustrated in Figure 3.9. In the next section,
e precise nature of this compatibility in the form of a principle for display design.
oximity Compatibility Principle (PCP)
ProximityCompatibilityPrinciple(PCP):
10, we summarize the one key implication of what we have just discussed. On the
ConceptofTaskCompatibility
e figure, two (or more) elements on a display
(or in the natural environment) can be
Display representation
Task list.
1._____
2._____
3._____
Task representation
Taskcompatibility:
Thewayataskisdisplayed
shouldbecompatiblewith
theactualinformationneeds
ofthattask.
FIGURE 3.9 Task compatibility refers to the relationship
between display and task representations.
71
9/8/12 1:09 AM
Recallearlierexampleofengine
parameterdisplays:
Left1-4;Right1-4;Left5-8;Right5-8
TheProximityCompatibilityPrinciple(PCP)
•  TaskProximity:Extenttowhichdifferentinformationsourcesare
actuallyprocessedtogetherwithinthesametask.
–  (a.k.a.‘processingproximity’or‘mentalproximity’)
–  dividedattentionismanifestedasmentalinformationintegration(*)
•  DisplayProximity:How‘close’displayelementsaretoeachother
…w.r.t.eitherspatialorobject-baseddistance.
•  Ifinformationsourceswithinataskrequirehightaskproximity,
thentheyshouldhavehighdisplayproximity.
–  assistsinintegratinginformation
•  Ifinformationsourceswithinataskrequirelowtaskproximity,
thentheyshouldhavelowdisplayproximity.
–  assistsinseparatinginformationsources
–  usingintegrateddisplayswhentaskrequireslowtaskproximitycan
beadisadvantage;canleadtoresponseconflict
(*dualtaskprocessing,includingresponses,tobedealtwithlater)
TheProximityCompatibilityPrinciple(PCP)
Chapter 3 • Attention in Perception and Display Space
Good
High task proximity
Divided attention
(information integration)
Performance
72
Low task proximity
Bad
Focused attention
Low (distant)
High (close)
By space
By objectness
Display proximity
FIGURE 3.10 An illustration of the proximity compatibility principle. The graph at the top of the
figure shows performance as a function of display and task proximity. The bottom part of the figure
shows two ways to manipulate display proximity: by distance or by objectness.
either “distant” from each other or “close,” where closeness can be defined by either spatial proximity (the circles) or belonging to the same object (“objectness,” the rectangles). This distinction
forms the x-axis of the graph above. On the y-axis we have plotted performance; the quality of
DimensionsofDisplayProximity
Chapter 3 • Attention in Perception and Display Space
73
Display proximity
Sensory/perceptual differences
Howcanwemanipulate
DisplayProximity?
Proximity in:
1. Space
o o (vs. o
2. Color
o o (vs.
o)
Separation
o)
Common object
3. Connections
o
o
4. Abutment
5. Heterogeneous feature
6. Homogeneous feature
(size,brightness,shape)
or
y
7. Homogenous feature
Emergent features
8. Homogeneous feature (again)
x
H
W
Area
Shape
9. Polygon display
FIGURE 3.11 Dimensions of display proximity.
perceptual similarities; common object; and emergent features. We describe these below, identified by row number in the figure.
Thisonedoesn’t!
DimensionsofDisplayProximity
Chapter 3 • Attention in Perception and Display Space
Display proximity
Thislabelrelatestothisfigure.
Sensory/perceptual differences
Proximity in:
1. Space
o o (vs. o
2. Color
o o (vs.
o)
Separation
o)
Common object
3. Connections
o
o
4. Abutment
5. Heterogeneous feature
6. Homogeneous feature
or
y
7. Homogenous feature
Emergent features
8. Homogeneous feature (again)
9. Polygon display
x
H
W
Area
Shape
73
Sensory/perceptual differences
Proximity in:
DimensionsofDisplayProximity
Separation
o)
1. Space
o o (vs. o
2. Color
o o (vs.
o)
Common object
3. Connections
o
o
4. Abutment
5. Heterogeneous feature
6. Homogeneous feature
or
y
position
7. Homogenous feature
Emergent features
8. Homogeneous feature (again)
x
H
W
Area
Shape
9. Polygon display
FIGURE 3.11
Dimensions of display proximity.
al similarities; common object; and emergent features. We describe these below, identiw number in the figure.
•  Heterogeneousfeaturestypicallyusedforseparabledisplays
•  Homogeneousfeaturescanbeseparableorintegral
Close proximity in space (or spatial contiguity; Ginn, 2006). As we have discussed, spacebased proximity is related strongly to the effort required to move attention (and particu-
NSORY/PERCEPTUAL SIMILARITIES
4. Abutment
5. Heterogeneous feature
or
y
DimensionsofDisplayProximity
6. Homogeneous feature
7. Homogenous feature
Emergent features
8. Homogeneous feature (again)
x
H
W
Area
Shape
9. Polygon display
(a)symmetry
FIGURE 3.11
Dimensions of display proximity.
larities; common object; and emergent features. We describeversus:
these below, identimber in the figure.
/PERCEPTUAL SIMILARITIES
proximity in space (or spatial contiguity; Ginn, 2006).
As we have discussed, spaceSomedisplayscanbeconfiguredtocreate
emergentfeatures
proximity is related strongly to the effort required
to move attention (and particuhe eyes) from one location to another. One example is the book designer’s goal to
SampleGraphfromRecentThesis
Graphinfirstdraftofthesis.
Todistinguishbetweenconditions,
usedonly:
•  colour(sensorydifferences)
•  heterogeneousfeatures(shape
ofsymbols)
Problem:requiredsignificanteffort
tomentallyassociatepointsand
inferpotentialtrendsand/or
relationshipsamongconditions.
Samedatainfinalthesis.
Todistinguishbetweenconditions,
used:
•  colour(sensorydifferences)
•  heterogeneousfeatures(shapeof
symbols)
•  connections(linesjoiningdatafrom
samecondition)
•  redundantcolour(lines&points)
Example:ClusterAnalysis
Napoleon’sMarchThroughRussia,1812-13
(SeeTufte)
Summary:Focused/DividedAttention
PositiveAspectsofParallelProcessing
•  ifinformationsourceshavethesameorsimilar
meaning(i.e.redundancygain)
–  e.g.colour+shapecoding
–  e.g.objectdisplays(e.g.temperatureandpressure)
•  also…ifinformationsourceshaveindependent
implications,butarenon-interfering
–  e.g.computercursor
–  e.g.flightdirectors
Summary:Focused/DividedAttention
NegativeAspectsofParallelProcessing
•  wheninformationsourcesincloseproximity
haveincompatibleresponseimplications
–  e.g.Stroopeffect
•  resourcecompetition:wheninformation
sourcesincloseproximitycompeteforthe
sameperceptualanalysers–inotherwords,
“displayclutter”
–  e.g.followingtwoauditorymessagesatonce
–  e.g.monitoringtwoadjacent,similardisplays
–  e.g.Brooks’memorytask(tobestudiedlater)
GuidelinesforDesigningTasksInvolving
Divided Attention
•  Useintegraldisplays(highproximity),asappropriate
–  (butthesearenotnecessarilyalwaysappropriate!)
•  Maintainconformality,asappropriate
•  Minimisenumberofpotentialsourcesofinformation**
•  Iftimesharingisnecessary,indicate,wherepossible,the
relativeprioritiesoftasks/stimuli
•  Whenappropriate,optimise(ratherthanjustminimise)
loadlevelofsecondarytasks.
•  Minimisedifficultyleveloftasks,wherepossible
**Distracteddrivingisdangerous;
don’tusemobilephone(talkingortexting)whiledriving!
GuidelinesforDesigningTasksInvolving
FocusedAttention
•  Separatecompetingchannelsphysically,asfarapartas
possible
•  Makecompetingchannelsasdistinctfromeachother
aspossible
•  Minimisethenumberofcompetingchannels
•  Maximisesalienceofthemostimportantchannel(s),
usingcolour,brightness,loudness,centrallocation,etc.
AttentionintheAuditoryModality
Comparedtovisualmodality:
•  Auditorymodalityisomnidirectional
–  incontrasttovisualattention;no“earball”
–  (butsomeabilitytoattendtolocalisedsoundsources)
•  Auditorymodality(almost)always“on”
–  i.e.indark,evenwhensleeping
•  Mostauditoryinputsaretransient
–  heldinshorttermsensorystore,andthenvanishes
–  (auditorySTSSlongerthanvisualSTSS)
•  Auditoryinputshavegoodchanceofbeingnoticed
–  Advantageforauditorywarningsignals(vsvisual)
–  Disadvantageifneedtoignoreirrelevantsounds
AttentionintheAuditoryModality:
TheCocktailPartyEffect
1
5
2
3
4
6
WallStreetJournal,23/4,2012
ClassicalResearchonAuditoryAttention:
DichoticListeningTask
• Subjectrequiredto‘shadow’inputfromoneear,whileignoringinputfromotherear
• Experimenterkeepstrackoferrors…andwhethercontentfrom‘ignoredear’appearsinoutput
www.simplypsychology.org/attention-models.html
ClassicalResearchonAuditoryAttention:
Broadbent’sFilterModelofSelectiveAttention
•  attendingtooneparticulareardependsondistinguishablecharacteristics
•  e.g.whichear,typeofvoice,gender,etc.
•  filteringblocksoffonesource,infavourofanother
•  semanticprocessinghappensafterthefilter
•  takestimetoswitch(~500ms)
www.simplypsychology.org/attention-models.html
ClassicalResearchonAuditoryAttention:
Treisman’sAttenuationModel
•  tocounterweaknessinBroadbentmodel
•  e.g.CocktailPartyeffect:‘unattended’informationneverthelessperceived
•  filterattenuates,ratherthaneliminates,unattendedmaterial
•  allowsperceptionofownname,plusotherimportantmaterial
www.simplypsychology.org/attention-models.html
AuditoryDividedAttention
•  dividedattentionachievedbyrapidswitchingbetweensources
•  reliesonretentionofinformation(forafewseconds)inSTSS
•  easiertoswitchoverifunattendedinformationiscontextually
pertinent(e.g.ownname)
•  possibletodesignlessintrusiveauditorywarningsbyrelyingon
personalisedalerts,expertexperience,etc.
•  possibletocreate‘auditoryobjectdisplays’
–  e.g.words+melodyofsongs,meaning+voiceinflections
–  e.g.auditoryalerts,thatcombinepitch,loudnessandtimbre
–  e.g.sonificationdisplays,inmedicine,music,seismology,etc.
•  demo:http://www.youtube.com/watch?v=zoagpsLd8iM
AuditoryFocusedAttention
•  cocktailpartyeffectexemplifiesabilitytofocusononesource
–  manifestsasauditorystreamsofstableanddistinctauditoryobjects
–  e.g.differentvoices,differentinstrumentsinorchestra,etc.
–  mediatedbypitch,timbre,spatiallocation,timing,etc.
•  easiertofocuswithdichoticlistening,relativetomonaural
•  despiteomni-directionality,abletolocalisesoundinspace
•  canusespatiallylocalisedsoundforseparateauditorychannels
–  e.g.headphones,speakerarrays,etc.
–  e.g.cuingofwarningsignals