- Human-computer interaction (HCI) is the study and the design of interaction between people and computers.
- Human-computer interaction is a discipline concerned with the design, evaluation and implementation of interactive computing systems for human use and with the study of major phenomena surrounding them.  (Hewett et al., 2004).
- Design methodologies in HCI aim to create user interfaces that are usable, i.e. that can be operated with ease and efficiency. However, an even more basic requirement is cognitive usability, ie. that the user interface be useful allowing the user to complete relevant tasks within a task environment.
- e.g. Ethnography
- User-centered designs (UCD), e.g. participatory design, design-based research, scenario-based design
Designing for HCI
Explaining the impact of computers on design as an activity, Hoffman, Roesler and Moon (2004) offer the following:
- User needs analysis
- Define the analysis framework and methodology
- Define contents and concepts
- Acquire and categorize mental representations
- Define the interface "language"
- Prototype creation
- Usability and cognitive ergonomics testing
In a computer-based environment an interaction can be defined as “the representations and operations of an application system by considering what representations the user needs to interact with, through what operations.” (Yamamoto and Nakakoji, 2005)
Interaction design principles
Vita Hinze-Hoare formulated four fundamental design principles. Her theory is based on an analysis of Dix (2003), Schneiderman (1998) and Preece (1994), discussion with peers and a user survey:
- Learnability/Familiarity: for example, reduce short term memory load, ensure ease of understanding and guessability, make operations visible, use appropriate metaphors.
- Ergonomics/Human Factors: for exemple, allow for flexible input (like menus, shortcuts, panels), multiple communication, design for user growth
- Consistency/Standards: for example, likeness in behavior, consistent and clear user interface elements
- Feedback/Robustness: give appropriate quantity of response, offer informative feedback, let the user recover from errors or dead-ends, insure stability, task completeness and adequacy, respond in time.
Ladly outlines some guidelines in designing interactions:
- Visibility - knowing the stat of an object and the choices available
- Feedback - timely, in an appropriate mode (aural, visual, etc.), yet not distracting from task
- Affordance - use object whose actual properties are in accordance with its perceived properties (e.g. an icon depicting a switch should turn something on or off)
- Mapping - make use of the relationship between objects and their environment (e.g. placing a menu bar at the top of an application window)
- Constraints - limit the possible interactions physically, semantically (context-related meaning), logically, or culturally (learned conventions)
- Habituation - the use of the system should become internalized to the point that the user only thinks of the task, not the system
A cognitive interactive interface should invoke and respond to only one action from the user. (Ladly, 2004)
HCI design approaches
One view of design is that it is an activity that aims to solve contextual problems systematically (Hoffman, Roesler & Moon, 2004)
- Top-down or hierarchical problem solving - working from the functional level to the specific working out issues problems that arise
- Design by reuse - use of previous designs that are based on similar situations
- Design problem evolution - recognition and relaxation of assumptions thus engaging in a redefinition of the problem in cycles that involve planning, translating and revising in order to optimize a system so that it can satisfy diverging and contradictory requirements
- Design by deliberative recognition-priming - use of previous conceptual knowledge and experience to recognize useful patterns to by-pass hierarchical processes
- Design by serendipitous recognition-priming - ideas that arise from opportunistic comparisons and analogies not necessarily directly related to the design problem.
- Design by collaboration and confrontation - team-based design based on collaboration and confrontation activities.
Tom Erickson (1995) outlines some ways in which storytelling can be used as a tool for designing human-computer interactions. Stories reveal users' experiences, desires, fears and practices that can in turn drive effective user-centered design. He points out that stories, in contrast to scenarios, involve real people in particular situations and consequently involve unique histories, motivations and personalities.
- story gathering - gathering users' stories on the users' domain (a culturally, socially and physically situated environment) thereby collecting and building a shared language, referents and questions and issues to be addressed.
- story making - building 'scenario-like' stories that capture emerging common concepts and details from users' stories
- involving users - using stories with users to elicit dialog and discussions that bring essential ideas and problems to light that should be considered in the design.
- transferring design knowledge - being highly memorable and still susceptible to the uncertainty entailed in the particular being applied to the whole, “stories become important as mechanisms for communicating with the organization by upport design transfer”, by “capturing both action and motivation, both the what and the why of the design” (Erickson, 1995)
Personas in interaction design
Design of an interaction sets the conditions in which a conversation between a user and a system will take place. The system needs to speak and respond to the user. To envision more effectively how such a conversation may proceed, interaction designers determine user personas. Personas are defined models of intended and potential user types. These models can be defined through ethnographic research practices such as observation, interviews or direct user-testing with sample target users. Personas are widely used in user-centered design approaches.
- Interaction-design.org Encyclopedia Contains some good introductory articles regarding various HCI domains. Good place to start.
- Wikipedia: Human computer interaction
- HCI Bibliography Lots of pointers (e.g. an index of 34000 articles, pointers to introductory books, some on-line texts)
- Ten Usability Heuristics by Jakob Nielsen
- Introducing interaction design article series and interesting discussion on ID and IA at Boxes and Arrows a peer-written journal “devoted to the practice, innovation, and discussion of design; including graphic design, interaction design, information architecture and the design of business”.
- Erickson, T. Notes on Design Practice: Stories and Prototypes as Catalysts for Communication. based on a version of this paper that appeared in Scenario-Based Design: Envisioning Work and Technology in System Development. (ed. J. Carroll). New York: Wiley & Sons, 1995. 
- Dix et al (2003). Human computer interaction, 3rd Edition, Prentice Hall, ISBN 0130461091
- Dourish Paul (2006). Implications for Design, CHI 2006 paper, PDF
- Hewett, Baecker, Card, Carey, Gasen, Mantei, Perlman, Strong and Verplank (2004). ACM SIGCHI Curricula for Human-Computer Interaction, Chapter 2: Human-Computer Interaction HTML - retrieved 17:47, 9 June 2006 (MEST).
- Hinze-Hoare, Vita (2004). Four Principles Fundamental to Design Practice for Human Centred Systems, Abstract/PDF.
- Hoffman, R., Roesler, A., Moon, B. (2004). What Is Design in the Context of Human-Centered Computing? Human-Centered Computing. IEEE Computer Society. JULY/AUGUST 2004
- Ladly, M. (2004). Interaction Design Workshop: Part One: workshop presentation at Banff New Media Institute audio presentation PDF
- Preece, Jenny (1994). Human Compter Interaction, Addison Wesley, ASIN B000OOI3AQ.
- Preece, Jenny (2000). Online Communities: Designing Usability and Supporting Sociability, Wiley, ISBN 0471805998. (This gets mixed reviews).
- Shneiderman, Ben (1998). Designing the User Interface. Addison Wesley, ISBN-10: 0201694972
- Shneiderman, Ben (2000) Universal Usability, Communications of the ACM, May 2000,Vol 43 Nr. 5
- Sharp Helen, Yvonne Rogers and Jenny Preece, (2007) Interaction Design: Beyond Human-Computer Interaction, 2nd edition, Wiley, ISBN 0470018666
- Yamamoto, K. Nakakoji, Y. (2005). Hypertext representations as a means for creative knowledge work New Review of Hypermedia and Multimedia, Vol. 11, No. 1, p. 39-67.