Select the Proper Kinds of Windows

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Select the Proper Kinds of Select the Proper Kinds of WindowsWindows


Human Task SwitchingHuman Task Switching

Types of Task SwitchingTypes of Task Switching– InterruptionInterruption– Need to find missing process or Need to find missing process or

informationinformation– Human initiated restHuman initiated rest

Effect of Task SwitchingEffect of Task Switching– Cognitive attention lostCognitive attention lost– Cognitive load increasesCognitive load increases


Task Switching - InterruptionsTask Switching - Interruptions

For today’s Information WorkerFor today’s Information Worker– interruptions are part of individual’s dayinterruptions are part of individual’s day

• many people are interrupted 10 timesmany people are interrupted 10 timesin each short taskin each short task

– interruptions require the individual to:interruptions require the individual to:• either search for their location in the either search for their location in the

task they are doingtask they are doing• or mentally record where they are in or mentally record where they are in

the taskthe task


Task Switching - Self initiated Task Switching - Self initiated

People also interrupt their own People also interrupt their own tasktask– many tasks are complex enough that many tasks are complex enough that

humans lose track of where they are humans lose track of where they are and restart themand restart them

– many tasks are cognitively many tasks are cognitively demanding and require mental restsdemanding and require mental rests• humans switch to reading their email humans switch to reading their email

or more routine tasks for this restor more routine tasks for this rest


Task Switching--Incomplete Task Switching--Incomplete Preparation Preparation

People do not organize and plan People do not organize and plan their work for the week, day, hour their work for the week, day, hour except in a very general wayexcept in a very general way

People carry out the next detailed People carry out the next detailed part of their task based on the part of their task based on the visual and auditory cues that are visual and auditory cues that are currently present in their taskcurrently present in their task


Knowledge - NormanKnowledge - Norman

In the head...and in the worldIn the head...and in the world We behave precisely without We behave precisely without

precise knowledgeprecise knowledge– Information is in the worldInformation is in the world– Natural constraints are presentNatural constraints are present– Cultural constraints are present Cultural constraints are present – Precise memory is not requiredPrecise memory is not required


Knowledge in the Head vs. in the WorldKnowledge in the Head vs. in the WorldProperty Knowledge in the

WorldKnowledge in theHead

Retrievability When visible oraudible

Not readily retrievable,requires memory searchor remembering

Learning Learning not required,interpretationsubstitutes forlearning

Requires learning, oftenconsiderable. Goodmental models help

Efficiency of Use Can be slowed byneed to find andinterpret externalinformation

Can be very efficient

Ease of Use atFirst Encounter

High Low

Aesthetics Aesthetics depends ondesigner skill, can becluttered

More design freedom,since nothing needs to bevisible


Incomplete PreparationIncomplete Preparation

ExampleExample– Cooking potatoes:Cooking potatoes: after the potatoes after the potatoes

have been washed, we use the visual have been washed, we use the visual cue of the washed potatoes with skins cue of the washed potatoes with skins on to tell us we have to peel them on to tell us we have to peel them

– Similarly, when they are peeled, we Similarly, when they are peeled, we know the next step is to cook themknow the next step is to cook them



Use of external cues to tell us Use of external cues to tell us where we are in the task is known where we are in the task is known as as Situated ActionSituated Action

Reliance on situated action means Reliance on situated action means that we often remember we need a that we often remember we need a crucial piece of information only in crucial piece of information only in the middle of the taskthe middle of the task



For example, in cooking the potatoes, For example, in cooking the potatoes, we may suddenly realize we need salt we may suddenly realize we need salt and have to run to the store to get saltand have to run to the store to get salt

In short, we are not really forgetful; it In short, we are not really forgetful; it is cognitively easier for us to do the is cognitively easier for us to do the task via situated action then to plan task via situated action then to plan aheadahead

This leads to lots of This leads to lots of task switchingtask switching


Effect of Task SwitchingEffect of Task Switching Loss of task attentionLoss of task attention

– Tasks require place-keepers for people Tasks require place-keepers for people to return to them at the point where to return to them at the point where they switched awaythey switched away

– If the place-keepers are not available If the place-keepers are not available visually, they have to be maintained visually, they have to be maintained mentallymentally

– Even with visual place-keepers, there is Even with visual place-keepers, there is some mental overhead in task switching some mental overhead in task switching


Task Switching ManagementTask Switching Management

Because task switching is inherent in Because task switching is inherent in the social and psychological makeup the social and psychological makeup of human work, humans have of human work, humans have developed strategies for handling itdeveloped strategies for handling it– they lay out their work on a surface to they lay out their work on a surface to

be able to move from task to taskbe able to move from task to task– they create patterns in their layout to they create patterns in their layout to

help them find and return to a particular help them find and return to a particular tasktask


How People Manage their DesktopsHow People Manage their Desktops

People have done studies of how people People have done studies of how people manage their desk in hopes of providing manage their desk in hopes of providing computer tools to support the taskcomputer tools to support the task

People are either orderly or very messy, People are either orderly or very messy, but the real issue here is that people but the real issue here is that people have a have a visual sensevisual sense of the layout of of the layout of paperspapers

They use this visual picture to help They use this visual picture to help them find thingsthem find things


How People Manage their DesktopsHow People Manage their Desktops

People lay out items on their desk People lay out items on their desk as remindersas reminders

People lay out items on their desk People lay out items on their desk so they can do task switchingso they can do task switching

People lay out items on their desk People lay out items on their desk so they can see the relationships so they can see the relationships among the itemsamong the items


Windows: Support forWindows: Support forTask SwitchingTask Switching

In the beginning, people had one In the beginning, people had one application running on their computer at application running on their computer at a timea time

Because we are constantly switching Because we are constantly switching tasks, this became intolerabletasks, this became intolerable– exit program 1exit program 1– enter program 2enter program 2– exit program 2exit program 2– enter program 1enter program 1

Windows solve this problemWindows solve this problem


Windows: Our Virtual Messy Desk!Windows: Our Virtual Messy Desk!

People use windows exactly like they People use windows exactly like they use stacks of papers on their desksuse stacks of papers on their desks

But: task switching with windows is But: task switching with windows is often like searching a very messy deskoften like searching a very messy desk– built by programmers for programmersbuilt by programmers for programmers– windows appear in strange places and windows appear in strange places and

inconvenient sizesinconvenient sizes– like the QWERTY keyboard, we now mustlike the QWERTY keyboard, we now must

live with themlive with them


WindowsWindows

OverviewOverview ComponentsComponents Presentation stylesPresentation styles TypesTypes OrganizationOrganization OperationsOperations

Chart-o-matic X


Some Uses of WindowsSome Uses of Windows Support for human userSupport for human user

– Provide knowledge in the worldProvide knowledge in the world– Reflect the way people workReflect the way people work

Presentation of informationPresentation of information– Different levels, kinds, and sequencesDifferent levels, kinds, and sequences– Different sourcesDifferent sources

Performing more than one taskPerforming more than one task RemindingReminding MonitoringMonitoring


Windows ComponentsWindows Components


Window Components--Win 98Window Components--Win 98Windows Containing Component

ComponentPrimary Secondary Dialog Box

Frame or Border X X X

Title Bar Text X X X

Work Area X X

Title Bar Icon X

Window Sizing Buttons X X X

Menu Bar X

Status/Message Bar X

Scroll Bars X

Size Grip X


Window Presentation StylesWindow Presentation Styles TiledTiled

– Single task activitiesSingle task activities– Tasks with little window Tasks with little window

manipulationmanipulation– Novice or inexperienced usersNovice or inexperienced users

Overlapping and cascadingOverlapping and cascading– Switching between tasksSwitching between tasks– Window manipulation neededWindow manipulation needed– Expert or experienced usersExpert or experienced users

Disadvantages of each typeDisadvantages of each type??


Disadvantages of Presentation StylesDisadvantages of Presentation Styles

TiledTiled– Limited screen Limited screen

sizesize– Open windows Open windows

change size & change size & positionposition

– Windows get tinyWindows get tiny– Look crowdedLook crowded– Less user controlLess user control

OverlappingOverlapping– More complex, More complex,

possibly possibly distractingdistracting

– Information gets Information gets hidden or losthidden or lost

– Users don’t always Users don’t always recognize 3-D recognize 3-D modelmodel


Types of WindowsTypes of Windows Primary or ApplicationPrimary or Application Secondary, Document, or SupplementalSecondary, Document, or Supplemental

– Property WindowsProperty Windows

– Dialog BoxesDialog Boxes • Modal or ModelessModal or Modeless

– Message BoxesMessage Boxes– Palette WindowsPalette Windows– Pop-Up Windows (e.g., paper clip guy)Pop-Up Windows (e.g., paper clip guy)


Property WindowsProperty Windows

Displays Displays accessible accessible properties of properties of objectobject

Information is Information is grouped using grouped using tabbed pagestabbed pages


Dialog BoxesDialog Boxes

Get additional Get additional information from information from useruser

Common dialogsCommon dialogs– OpenOpen– SaveSave– PrintPrint


Message BoxesMessage Boxes

Provides Provides information to the information to the useruser

Standard typesStandard types– InformationInformation– WarningWarning– Critical errorCritical error


Palette WindowsPalette Windows Presents a collection of Presents a collection of

controls-- graphical or controls-- graphical or pictorialpictorial

Mutually exclusive Mutually exclusive choices--like radio choices--like radio buttonsbuttons– PalettesPalettes– ToolbarsToolbars


Pop-Up WindowsPop-Up Windows

Displays additional Displays additional informationinformation

Most standard Most standard secondary window secondary window components components omittedomitted

Example: tooltipsExample: tooltips


Types of WindowsTypes of Windows

Single Document Interface (SDI)Single Document Interface (SDI) Multiple Document Interface (MDI)Multiple Document Interface (MDI) WorkspacesWorkspaces WorkbooksWorkbooks ProjectsProjects


MDI WindowsMDI Windows


Organizing WindowsOrganizing Windows

Organize windows to support user Organize windows to support user taskstasks– Rather than organizing by features, Rather than organizing by features,

functions, or ease of implementationfunctions, or ease of implementation Minimize the number of windows Minimize the number of windows

needed to perform a taskneeded to perform a task– Focus on common tasksFocus on common tasks


Sizing WindowsSizing Windows

Large enough toLarge enough to– Contain expected informationContain expected information– Avoid hiding important informationAvoid hiding important information– Avoid crowdingAvoid crowding

Otherwise, as small as possible!Otherwise, as small as possible!– Text - about 12 linesText - about 12 lines– Alphanumeric - about 7 linesAlphanumeric - about 7 lines


Window OperationsWindow Operations

General GuidelinesGeneral Guidelines– Focus on ease of use and learningFocus on ease of use and learning– Less is moreLess is more– Give users control / ability to tailorGive users control / ability to tailor

• Especially for overlapping windowsEspecially for overlapping windows!!

Keyboard Control/Mouseless Keyboard Control/Mouseless OperationOperation

Opening…Placement…Separation…Moving…Resizing…Shuffling…Closing


Limitations of WindowsLimitations of Windows

Little research on window Little research on window design/usedesign/use

Hardware limitationsHardware limitations Human limitationsHuman limitations

Select the Proper Kinds of Windows

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