What is HCI?

Short for Human-Computer Interaction, HCI is a discipline concerned with the study, design, construction, and implementation of human-centric interactive computer systems.

HCI Definitions

• The design and implementation of computer systems that people interact with. It includes desktop systems as well as embedded systems in all kinds of devices.
• HCI is a large discipline that deals not only with the interface design but with the reasoning for building the functionality into the system in the first place.
• It is also concerned with the consequences of using the system over time and its effects on the individual, group, and company.

Why Study HCI?

People now expect “easy to use” systems:

• Generally, they are not tolerant of poorly designed systems.
• If a product is hard to use, they will seek other products.

Usability Requirements

Synonyms for “user-friendly” in Microsoft Word are easy to use, accessible, comprehensible, intelligible, idiot-proof, available, and ready. However, a “friend” also seeks to help and be valuable. A friend is not only understandable but understands. A friend is reliable and doesn’t hurt. A friend is pleasant to be with. These measures are still subjective and vague, so a systematic process is necessary to develop usable systems for specific users in a specific context.

Usability Motivations

Life-critical systems:

• Air traffic control, nuclear reactors, power utilities, police & fire dispatch systems, medical equipment.
• High costs, reliability, and effectiveness are expected.
• Lengthy training periods are acceptable despite the financial cost to provide error-free performance and avoid low-frequency but high-cost errors.
• Subject satisfaction is less of an issue due to well-motivated users.

Industrial and commercial uses:

• Banking, insurance, order entry, inventory management, reservation, billing, and point-of-sale systems.
• Ease of learning is important to reduce training costs.
• Speed and error rates are relative to cost.
• Speed of performance is important because of the number of transactions.
• Subjective satisfaction is fairly important to limit operator burnout.

Office, home, and entertainment applications:

• Word processing, electronic mail, computer conferencing, video game systems, educational packages, search engines, mobile devices, etc.
• Ease of learning, low error rates, and subjective satisfaction are paramount due to use often being discretionary, and competition is fierce.
• Infrequent use of some applications means interfaces must be intuitive and easy to use; online help is important.
• Choosing functionality is difficult because the population has a wide range of both novice and expert users.
• Competition causes the need for low cost. (e.g., Nintendo Wii - exploratory, creative, and cooperative systems)

Exploratory, creative, and cooperative systems:

• Web browsing, search engines, artist toolkits, architectural design, software development, music composition, and scientific modeling systems.
• Collaborative work.
• Benchmarks are hard to describe for exploratory tasks and device users.
• With these applications, the computer should be transparent so that the user can be absorbed in their task domain.

Social-technical systems:

• Complex systems that involve many people over long time periods.
• Voting, health support, identity verification, crime reporting.
• Trust, privacy, responsibility, and security are issues.
• Verifiable sources and status feedback are important.
• Ease of learning for novices and feedback to build trust.
• Administrators need tools to detect unusual patterns of usage.

HCI Disciplines

• Cognitive Psychology: Understanding human behavior and mental processes.
• Neuroscience: Neuroscience enables us to build more accurate and robust models of human cognitive functions. These models may allow us to evaluate usability and predict user behavior. It has the potential to close the gap between humans and computers.
• Ergonomics or Human Factors: User-Equipment Design-Environment.
• Engineering & Computer Science: Faster machines, faster systems, building better interfaces.
• Design: Interface layout.
• Anthropology: User body shape.(e.g., keyboard design originated from the type writer)
• Sociology: Groupware. Considers the introduction of IT in society.
• Philosophy: Philosophy of technology. Create consistency.
• Linguistics: Language for commands.
• Artificial Intelligence: Simulating human behavior.

Ergonomics

• Physical aspects of interfaces.
• Study of the physical characteristics of interaction.
• Ergonomics are good at defining standards and guidelines for constraining the way we design certain aspects of systems to suit the environments and users.

Ergonomics - Examples

• Arrangement of controls and displays: Controls grouped according to function or frequency of use, or sequentially (mapping).
• Surrounding environment: Seating arrangements adaptable to cope with all sizes of users (e.g., movie theatre).
• Health issues: Physical position, environmental conditions (temperature, humidity), lighting, noise.
• Use of color: Use of red for warning, green for okay, awareness of color-blindness, etc.