©2001 Southern Illinois University, Edwardsville All rights reserved. Today Thursday CS 321 Human-Computer Interaction Design Elements Completed Reading:

©2001 Southern Illinois University, Edwardsville All rights reserved.

TodayToday

Thursday Thursday

CS 321 Human-Computer CS 321 Human-Computer InteractionInteraction

Design Elements Completed

Reading:ABF Ch.s 10, 11, 13& 14

Ethics

Reading:CKR pp. 13 – 40Please do not read ahead


Interesting Interfaces:Multi-touch sensing

Sent by Ross Mead

http://ted.com/tedtalks/tedtalksplayer.cfm?key=j_han&flashEnabled=1


Excise Tasks

Goal-directed tasks – actions that lead you directly toward reaching the goal

Excise tasks – supporting tasks that don’t lead you toward the goal but are necessary to accomplish it.

• Examples – window management, navigation, confirmation of actions

Eliminating excise makes the user more effective


Eliminating Excise and Expert Users

“Don’t weld on training wheels”

• Training screens should easily be turned off


Eliminating Excise: making intelligent decisions

Which com port should I choose?


Eliminating Excise: Halting Interruptions

Don’t stop the proceeding with idiocy

• Non-essential messages, confirmation dialogs, error messages that users can’t deal with or don’t care about.


Navigation

Any action that takes the user to a new part of the interface or which requires him/her to locate objects, tools. Or data.

• Poor navigation is a critical obstacle to usability Common types of navigation

• Between multiple windows or screens

• Between panes in a window

• Between tools or menus

• Within information displayed in a frame, such as scrolling


Navigation between multiple windows Gross shifting of attention Context switch overhead – disrupts flow Additional windows management Sovereign posture – single window/multiple panes


Navigating between multiple panes

Too many panes can cause visual clutter and confusion More scrolling Minimize panes, possibly use tabs


Navigating between tools and menus

Spatial organization in a pane or window is critical to reducing extraneous mouse movements

• Annoying

• Fatigue

• RSI’s Reserve menus for

rare items Group related tools


Improving Navigation

Sign posts – persistent objects that serve as a reference point


Improving Navigation

Provide appropriate mapping of controls


Inflecting Navigation

Organization of an interface so that typically used functionality is made most conveniently accessible

• Frequency of use

• Degree of dislocation

• Degree of exposure Users make commensurate effort if the rewards justify it.


Could an HCI Specialist have prevented the 2000 Could an HCI Specialist have prevented the 2000 Election Problems?Election Problems?

Palm Beach County Poll Butterfly Ballot

Why did the Florida Residents have such a difficult time using the Voto-matic Voting Machines?


What is a Chad?What is a Chad?

Hanging Chad: Two or Three Corner

Pregnant Chad

http://www.cs.uiowa.edu/~jones/cards/collection/chadhang.jpg

http://www.cs.uiowa.edu/~jones/cards/collection/votochad.jpg



Affordance – perceived properties of an artifact

Visibility – make apparent to users the actions they are allowed to take

Constraints – factors that encourage proper actions and prevent erroneous ones

Feedback – provides information about the effects of users’ actions

Prototype Testing



Actual Paper PrototypeActual Paper Prototype


Actual Paper PrototypeActual Paper Prototype


Actual Ballot




Internal consistency – are the elements within the interface coherent?

Organization – is the screen well laid out with proper use of white space? How is the balance? Is it cluttered causing cognitive overload?

Grouping – are the elements logically or haphazardly placed around the screen? Are they appropriately grouped? Are grouping aides such as alignment, borders, and Gestalt Principles properly used?




Hierarchy – Are the critical elements emphasized over the non-critical ones?

Simplicity – Excess or extra items that serve as distractions?

Legibility / Readability – Good choice of font and font size? Good use of white space?

Innovation – Did it benefit the voters or the candidates?




I can tell you, regular people get tripped up by the simplest things. It is sobering to observe a test where a user repeatedly asks "How do I go to the next step?" and you want to scream "Click the 'Next' button!" that they just somehow can't see. You thought the button was obvious, but, as anyone who's missed a highway exit learns, in the real world what's obvious to one person who knows the answer is not always obvious to a newcomer. People who are making fun of the voters who made mistakes should think about the obvious mistakes they've made in their lives. If "most people" never have problems doing simple things why were there so many flashing 12:00s on old VCRs? Would usability testing (which often only uses 5-20 people of each background) have caught it? I think so.

Dan Bricklin, Designer of VisiCalc and other widely used programs


Voting Machine Design


Documents

©2001 Southern Illinois University, Edwardsville All rights reserved. Today Thursday CS 321 Human-Computer Interaction Design Elements Completed Reading: