Presentation

Human Computer Interaction

and Usability Design

Audrey Troutt

Daniel Sheiner

Preview

Why usability matters What usability is Design Principles Usability Testing The Future of HCI

Why it matters

Human performance suffers under pressure Usable software sells Unusable software makes people unhappy

Definition of Usability

"Easy to use" "The extent to which a product can be used

by specified users to achieve specific goals with effectiveness, efficiency, and satisfaction in a specified context of use"

History

1970's Xerox Palo Alto Research Center (PARC)

Xerox Star WIMP (windows, icons, menus, pointers) paradigm WYSIWYG word processor

1982 First conference on computer usability SIGCHI

1998 International Organization of Standards First published standards for human-computer

interface design

Action

Write a research paper, play chess, read the news

Choose a font, move a bishop, open the New York Times website

Click mouse, press key Contract muscles

Seven Stages of Action

Forming the goal Specifying the intention Specifying the action Executing the action Perceiving the state of the world Interpreting the state of the world Evaluating the outcome

Conceptual Model

Cognitive representation: Functions Mapping of controls to functions Actions

Good mapping: Intuitive One-to-one Visible

Visibility

We process images faster than language.

Visibility

Sensory stimulation improves memory Emotion associated with information

improves memory Graphics make a stronger impression on

memory than text

Stylistic Consistency

Abstract Logos vs. Metaphors

Culturally Familiar Metaphors

One to one correspondence

One function per control facilitates graphical representation.

A visible control with one function reminds the user of its function.

Multiple functions per control: lead to arbitrary mappings

less effective / efficient learning confusing / frustrating minimizes flexibility of application

Intuitive Mapping

It's easier to integrate new knowledge into memory if it relates to pre-existing knowledge.

Intuitive controls almost don't have to be learned. Use physical analogies and standardized practices.

Executing the Action

The more complex the action, the more opportunities for user error at every stage of action up to and including execution.

Automate as much of the action as possible without taking necessary control away from the user. Minimize controls Simplify controls

What if I NEED many controls?

Feedback

Beginners need it to learn. Experienced users need it to fix mistakes. It can provide useful information about the

program's state, enabling the user to better form the next goal.

Visual feedback Audio feedback

Usable Explorable

Explorability is necessary for users to form complete conceptual maps.

Visible controls inspire curiosity about their functions.

Feedback directly demonstrates a control's function.

Minimize cost of error. Provide warnings before processing

irreversible actions.

Disabilities

Cognitive Impairments Physical Impairments Perceptual Impairments

Assistive Technologies

Screen Readers Braille Displays

Assistive Technologies

Speech recognition Head and eye tracking technology

Assistive Technology

Electrophysiological data

What can programmers do?

Provide flexible software that provides the same output in multiple formats and offers multiple ways for the user to issue similar commands.

Why is so much software unusable?

Engineers assume what's obvious to them is obvious to users.

Engineers lack familiarity with the details of the everyday activities their users will perform with the software.

Task Analysis

You must understand who the users are how these particular users think how they perform tasks without software how the software will improve their performance the range of resources available to users the environment in which users will use the

software Test at every stage

Usability Testing

User testing methods for software designers

Usability Testing Methods

User Surveys

Observation

Automated Testing

Special Users: Usability Testing with Children

User Surveys Provide subjective measure of overall user satisfaction.

Can indicate if usability problems exist Cannot identify causes of usability problems

Pre-designed surveys for software testing: QUIS—Questionnaire for User Interaction Satisfaction

Human-Computer Interaction Lab (HCIL) at the University of Maryland at College Park

http://www.lap.umd.edu/QUIS $1,000-$50 SUMI—Software Usability Measurement Inventory

University College Cork, Ireland

http://sumi.ucc.ie €2,500-Free PUTQ—Perdue Usability Testing Questionnaire

Perdue University

http://www.acm.org/perlman/question.cgi?form=PUTQ Free

Sample QUIS questions

5.4 Messages which appear on screen: confusing clear

1 2 3 4 5 6 7 8 9 NA

5.4.1 Instructions for commands or choice: confusing clear

1 2 3 4 5 6 7 8 9 NA

Sample SUMI questions


User Surveys

Observation

Automated Testing


Observation Simply observe people using your software without telling them

how it works. Gives enormous insight into assumptions you, the designer,

have made that don’t match up to the users’ experience. Low cost Can be used at any phase of development Even one or two observations can be useful

Observations can also be much more structured (and expensive) Hire professional usability specialists to observe Outsource observations to usability lab Large number of users Remote observation: test users worldwide

Observation: ten easy steps1. Set up the observation.

2. Bring in the user and describe the purpose of the observation.

3. Tell the user that it's okay to quit at any time.

4. Talk about and demonstrate equipment in the room.

5. Explain how to 'think-aloud'.

Kathleen Gomoll, “Some Techniques for Observing Users.” The Art of Human-Computer Interface Design. Brenda Laurel, Ed. (Massachusetts: Addison Wesley Publishing Company, 1990) 85.

Step 5: Explain how to ‘think-aloud’

User is asked to verbalize every thought, action and question while using the software

Observer records this information by hand, audio or video.

Advantage: Can provide valuable insight into the causes of and possible solutions to usability problems

Potential problem: Verbalizing actions and thoughts changes users’ experience with software

Observation: ten easy steps (cont.)

6. Explain that you will not provide help.

7. Describe tasks and introduce the product.

8. Ask if there are any questions before you start; begin the observation.

9. Conclude the observation.

10. Use the results.

Kathleen Gomoll, “Some Techniques for Observing Users.” The Art of Human-Computer Interface Design. Brenda Laurel, Ed. (Massachusetts: Addison Wesley Publishing Company, 1990) 85.

Observation: Discount Usability Engineering

Prototyping does not need to be expensive

You do not need to have a finished interface to start testing the ideas with users

Observation: Discount Usability Engineering

Example: Icon testing Print out icons Ask users to guess what the

icon represents Variability in responses means

an ambiguous icon. If no one guesses right, re-

design icon

Example: Cart sorting Write potential menu items on

index cards Have user sort cards into

stacks of related items Ask user to give each stack a

descriptive name Helps when designing menus

Examples borrowed from Jakob Nielsen and Bill Curtis. "Applying discount Usability Engineering." IEEE Software 12. 1 (Jan. 1995): 98-100.


User Surveys

Observation

Automated Testing


Automated Testing

Basic idea: Remove the observer Observations require observers, which can be expensive. Data from observations is filtered through observer.

Automatically record what users do with software, and maybe also video/audio recording for think-aloud.

History file: Recorded data including all input from user. For example: button clicks, mouse path, entered text. May be synchronized with video.

Automated Testing: Simulated Users

Artificially intelligent users “model the perceptual and cognitive processes of real users.”*

Possibly give the same kind of feedback as from history files or even think-aloud.

Only experimental applications have been developed.

*Kent L. Norman and Emanuele Panizzi. "Levels of Automation and User Participation in Usability Testing." Interacting with Computers 18. (2006): 246-264.

Automated Testing: Eye Tracking

In general, what the user looks at is what the user is thinking about.

Replaces think-aloud technique Data presented as a heat map

or gaze path.

“The eye is the mirror of the soul, and the soul is the mirror of our thoughts.” --John Elvesjo, founder of Tobii Technology (producer of eye-tracking hardware)

Automated Testing: Eye Tracking

Advantages Capture unconscious thoughts and

decisions—more data than from think-aloud

User is not distracted by having to think aloud

Disadvantages Cost Lab setting only Expertise needed to interpret data Devices look uncomfortable

Automated Testing: Mouse-tracking

Kent L. Norman and Emanuele Panizzi. "Levels of Automation and User Participation in Usability Testing." Interacting with Computers 18. (2006): 246-264.


User Surveys

Observation

Automated Testing


Usability testing with children Games and educational software for children make up a huge part

of software on the market. Usable software sells, but how can you test for usability with children?

What if your users can’t sit still through traditional observation? What if they can’t assign a number to their feelings about the

software?

*Gavin Sim et al.. "All work and no play: Measuring fun, usability, and learning in software for children." Computers & Education 26. (2006): 235-248.

The Smileyometer*

The Future of HCI design

The Future of HCI: Time for Revolution

There have been no major innovations in HCI design since 1976. That was when they came out with the WIMP (windows, icons,

mouse, pointer) interface.

The Future of HCI?The Multi-touch Screen

Described as “interface free”

Instead of WIMP interface, files, images, videos and running programs are more like physical objects you can touch, move and manipulate.

Video: Multi-Touch Screen Demo

Future of HCI: Existing Technologies

Eye-tracking

Speech Recognition

Most major innovations in HCI were first developed for use in games. So, look to video games for the next major innovation in

HCI design

HCI design and Usability Testing:THE END

Know your users

Test early and often

Image sources: slide number and link 6. http://www.vhml.org/theses/nannip/HCI_final_files/image001.gif

12. Norman, Donald A. The Design of Everyday Things. New York: Doubleday. 1990.

28. http://www.braillenet.org/accessibilite/livreblanc/images/braille3.jpg

29. http://www.boosttechnology.com/

32. Norman, Donald A. The Design of Everyday Things. New York: Doubleday. 1990.

45. http://www.nngroup.com/reports/prototyping/hifi_homepage_testing.jpg

45. http://people.csail.mit.edu/msbernst/tdr/usertesting.html

50. http://stephenslighthouse.sirsi.com/archives/thermal.png

50. http://www.uxmatters.com/MT/archives/000040.php

51. http://www.eyelinkinfo.com/optns_desk_optics.php

51. http://news.thomasnet.com/images/large/464/464278.jpg

57. http://cs.nyu.edu/~jhan/ftirtouch/

59. http://www.nevtron.si/borderline/archive2/intuiti.gif

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