Chapter 1 Overview
• Why HCI?– terminology
• HCI Challenges– change and functionality
• HCI Goals– usability
• HCI landmark systems• HCI importance
– productivity and problems
Why HCI?
• Shift from computers to people– expense vs ubiquity; wider range of “users”; larger market economics
• Terminology– user interface (Man-Machine Interface)
• those aspects of the system that the user comes in contact with; input language for user, output language for system, protocol for interaction
– Human-Computer Interaction (HCI) or Computer-Human Interaction (CHI)
• design, evaluation and implementation of interactive computing systems for human use and the study of the major phenomea surrounding them
Visibility and Affordance: Key principles for good HCI
• Artifact– An object produced or shaped by human workmanship
– format of input and style of feedback affect the success with which any artifact is used
• Visibility– Controls need to be visible with good mapping for their effects
• Affordances– refers to the property of objects: what sorts of operations and
manipulations can be done to a particular object
Affordances
• Does the design suggest that the door should be pushed or pulled? Aesthetics sometimes conflict with good affordances.
HCI Challenges
• Keeping abreast of changes in technology to ensuring that their design offers good HCI and harnesses the increased functionality of the new technology
• Example: feature phones
• Example: VCR
HCI Goals
• Usability– making systems easy to learn and easy to use
• Strive to– understand factors that determine how people use
technology
– develop tools and techniques to enable building suitable systems
– achieve efficient, effective, and safe interaction, both for the individual but also in groups
HCI Evolution
• GUI: Graphical User Interface
• WYSIWYG: What You See Is What You Get
• Xerox PARC: Dynabook (Alan Kay, 1970’s); Alto (1970’s); Star (1980’s product)
• Apple: Lisa (1980’s); Macintosh• Also consider SketchPad (Sutherland 1963);
NLS/Augment (Engelbart 1960’s on)
Benefits
• Word processing software (study in 1984)– improved turnover– greater flexibility– better use of staff
• IBM System installation– productivity improvement– customer satisfaction– $554.840 estimated net savings in a year
• DEC Application generator– 80% revenue increase; 30 to 60% over optimistic projections– improved usability (perceived by customers) and resulting increased
product sales
Working Practices
• Technology-induced changes– Job content: who does what, when, how, and how much
– Personnel policies (e.g., confidentiality of information)
– Job satisfaction: motivation, control, financial and other rewards, learning new skills
– Power and influence: individual and group
– Working environment
When Things Go Wrong
• See the RISKS digest– http://www.csl.sri.com/~risko/risks.txt– archives at ftp://ftp.sri.com/risks or
http://catless.ncl.ac.uk/Risks
Chapter 2 Overview
• HCI is interdisciplinary– Factors in HCI
– Disciplines contributing to HCI
• Conceptual model of HCI with four components– People, activities, the environment, technology
• HCI design– user centered, intergrates knowledge and expertise,
iterative
– evaluation
Factors in HCI
Organizational Factors Environmental Factors
Health and SafetyFactors
The User Comfort Factors
User Interface
Task Factors
Constraints
System Functionality
Productivity Factors
Disciplines contributing to HCI
• Computer Science
• Cognitive psychology
• Social and organizational psychology
• Linguistics
• Artificial Intelligence
• Philosophy, sociology, and anthropology
• Engineering and design
Conceptual model of HCI: components
• People– one or more people
• Work– narrowly or broadly defined activities including tasks or more
loosely defined activities
• Environment– physical, organizational, and social aspects of the environment
• Technology– any technological artifact, including workstations and computers
Model of HCILevel 3 Organizational goalSocial system
Technicalsystem
Level 2Work
ImmediateEnvironment
Level 1
People Technology
Broader environment
HCI Model Components
Constant interplay among model componentsA task implicitly sets requirements for the development of artifacts, and the use of an artifact often redefines the task for which the artifact was originally developed. For example, typewriting altered office tasks, word processors altered them again, desktop publishing systems altered them still more. In each case, changed tasks themselves suggested new needs and opportunities for further change.
Designing HCI
• Compare waterfall model of software design and user-centered HCI design model
• Waterfall model is a series of stages– Requirements analysis and definition
– System and software design
– Implementation and unit testing
– Integration and system testing
• HCI model is user-centered, intergrates different kinds of knowledge and expertise, iterative
User centered
• Involves users
• But who are the users that need to be involved?– end users– other stakeholders
• How should users be involved?
Intergrating different kinds of knowledge and expertise
• Sources of expertise– directly from a knowledge source– from tools developed by researchers and
consultants– from experts themselves
Making the design process iterative
Implementation Task analysis/functional analysis
Prototyping Evaluation Requirementsspecification
Conceptual design/formal design
The Star Life Cycle