Cognitive Science Project
Usability

Usability

• How well can a person utilize an interface?
• Can a task be completed?

Goals of User-Interface Design (What is the professional looking for in successful design)

• Time to learn interface
• Speed of performance in carrying out typical tasks
• Rate of errors by user
• Retention over time
• Subjective Satisfaction - this is the key in many cases!

Cognitive and Perceptual Abilities that can effect the usability of a design

• Short-term memory
• Long-term memory and learning
• Problem solving
• Decision making
• Attention and set
• Search and scanning
• Time perception

Are users stupid?

• Even the most expert users prefer simplicity rather than complexity!
• People with different strengths and weaknesses are going to have different needs when it comes to making an interface usable.
• The goal is to make the interface usable for the majority of the population that uses it!

Cultural and International Design Concerns

• Is the system going to be usable for the international community?
  • Characters, numerals, special characters, and diacriticals
  • Left-to-right vs. Right to left, vertical or horizontal
    • Asian Languages
  • Date and time formats
  • Numeric and currency formats
  • Weights and measures
    • Metric vs. English
  • Telephone numbers and addresses
  • Names and titles (Mr., Ms., Dr., etc)
  • Identification numbers, passports numbers
  • Capitalization and punctuation
  • Language and Grammar
    • Word Ending Syntax
    • Word Order Syntax
  • Etiquette, policies, tone, formality, metaphors

What are the design issues for persons with disabilities?

Use the Eight Golden Rules of Interface Design

• Strive for consistency
• Enable frequent users to use shortcuts
• Offer informative feedback
• Design dialogs to yield closure
• Offer error prevention and simple error handling
• Permit easy reversal of actions
• Support internal locus of control
• Reduce short-term memory load
  • simplicity better
  • seven-plus or minus-two

Getting the User's Attention

• Intensity
• Marking - bold, etc
• Size - Large vs. Small
• Choice of fonts- Is this easy to read?

Goals of Usability Testing

• Determine the needs of a user
• Simplicity
• Reach a wide range of users
• Quality
• Completion of tasks
• Satisfaction - This is the key

Usability of GUI Operating Systems

• Metaphors
• Menus
• Consistancy

Web Sites

Interface Hall of Shame
http://www.iarchitect.com/mshame.htm

Fixing Your Web Site
http://www.fixingyourwebsite.com/

Usability (government)
http://usability.gov/index.html

Good Web Design?
http://www.library.cmu.edu/Unofficial/WebCourse/webdesign.html

Color and Blinking
http://www.physics.brocku.ca/oapt97/webtut/principles.html 

Is this good or bad?
http://www.geocities.com/invokingirene/LIST.html

Color Example

Web Page Created by Jennifer L. Rowsam, 2002