Human–computer interaction
Human–computer interaction (HCI) is research in the design and the use of computer technology, which focuses on the interfaces between people (users) and computers. HCI researchers observe the ways humans interact with computers and design technologies that allow humans to interact with computers in novel ways. As a field of research, human–computer interaction is situated at the intersection of computer science, behavioral sciences, design, media studies, and several other fields of study. The term was popularized by Stuart K. Card, Allen Newell, and Thomas P. Moran in their 1983 book, "The Psychology of Human–Computer  Interaction." The first known use was in 1975 by Carlisle. The term is intended to convey that, unlike other tools with specific and limited uses, computers have many uses which often involve an open-ended dialogue between the user and the computer. The notion of dialogue likens human–computer interaction to human-to-human interaction: an analogy that is crucial to theoretical considerations in the field. Introduction. Humans interact with computers in many ways, and the interface between the two is crucial to facilitating this interaction. HCI is also sometimes termed "human–machine interaction" (HMI), "man-machine interaction" (MMI) or  computer-human interaction (CHI). Desktop applications, internet browsers, handheld computers, and computer kiosks make use of the prevalent graphical user interfaces (GUI) of today. Voice user interfaces (VUI) are used for speech recognition and synthesizing systems, and the emerging multi-modal and Graphical user interfaces (GUI) allow humans to engage with embodied character agents in a way that cannot be achieved with other interface paradigms. The growth in human–computer interaction field has led to an increase in the quality of interaction, and resulted in many new areas of research beyond. Instead of designing regular interfaces, the different research  branches focus on the concepts of multimodality over unimodality, intelligent adaptive interfaces over command/action based ones, and active interfaces over passive interfaces. The Association for Computing Machinery (ACM) defines human–computer interaction as "a discipline that is concerned with the design, evaluation, and implementation of interactive computing systems for human use and with the study of major phenomena surrounding them". An important facet of HCI is user satisfaction (or End-User Computing Satisfaction). It goes on to say: "Because human–computer interaction studies a human and a machine in communication, it draws from supporting knowledge on both the machine  and the human side. On the machine side, techniques in computer graphics, operating systems, programming languages, and development environments are relevant. On the human side, communication theory, graphic and industrial design disciplines, linguistics, social sciences, cognitive psychology, social psychology, and human factors such as computer user satisfaction are relevant. And, of course, engineering and design methods are relevant." Due to the multidisciplinary nature of HCI, people with different backgrounds contribute to its success. Poorly designed human-machine interfaces can lead to many unexpected problems. A classic example is the Three Mile Island accident, a nuclear meltdown accident, where investigations concluded  that the design of the human-machine interface was at least partly responsible for the disaster. Similarly, accidents in aviation have resulted from manufacturers' decisions to use non-standard flight instruments or throttle quadrant layouts: even though the new designs were proposed to be superior in basic human-machine interaction, pilots had already ingrained the "standard" layout. Thus, the conceptually good idea had unintended results. Human–computer interface. The human–computer interface can be described as the point of communication between the human user and the computer. The flow of information between the human and computer is defined as the  loop of interaction. The loop of interaction has several aspects to it, including: Goals for computers. Human–computer interaction studies the ways in which humans make—or do not make—use of computational artifacts, systems, and infrastructures. Much of the research in this field seeks to "improve" the human–computer interaction by improving the "usability" of computer interfaces. How usability is to be precisely understood, how it relates to other social and cultural values, and when it is, and when it may not be a desirable property of computer interfaces is increasingly debated. Much of the research in the field  of human–computer interaction takes an interest in: Visions of what researchers in the field seek to achieve might vary. When pursuing a cognitivist perspective, researchers of HCI may seek to align computer interfaces with the mental model that humans have of their activities. When pursuing a post-cognitivist perspective, researchers of HCI may seek to align computer interfaces with existing social practices or existing sociocultural values. Researchers in HCI are interested in developing design methodologies, experimenting with devices, prototyping software and hardware systems, exploring interaction paradigms, and developing models and theories of interaction. Design. Principles. The following experimental design  principles are considered, when evaluating a current user interface, or designing a new user interface: The iterative design process is repeated until a sensible, user-friendly interface is created. Methodologies. Various strategies delineating methods for human–PC interaction design have developed since the conception of the field during the 1980s. Most plan philosophies come from a model for how clients, originators, and specialized frameworks interface. Early techniques treated clients' psychological procedures as unsurprising and quantifiable and urged plan specialists to look at subjective science to establish zones, (for example, memory and consideration) when structuring UIs. Present-day models, in general , center around a steady input and discussion between clients, creators, and specialists and push for specialized frameworks to be folded with the sorts of encounters clients need to have, as opposed to wrapping user experience around a finished framework. Display designs. Displays are human-made artifacts designed to support the perception of relevant system variables and facilitate further processing of that information. Before a display is designed, the task that the display is intended to support must be defined (e.g., navigating, controlling, decision making, learning, entertaining, etc.). A user or operator must be able to process whatever information a system  generates and displays; therefore, the information must be displayed according to principles to support perception, situation awareness, and understanding. Thirteen principles of display design. Christopher Wickens et al. defined 13 principles of display design in their book "An Introduction to Human Factors Engineering". These principles of human perception and information processing can be utilized to create an effective display design. A reduction in errors, a reduction in required training time, an increase in efficiency, and an increase in user satisfaction are a few of the many potential benefits that can be achieved by utilizing these principles. Certain principles may not  apply to different displays or situations. Some principles may also appear to be conflicting, and there is no simple solution to say that one principle is more important than another. The principles may be tailored to a specific design or situation. Striking a functional balance among the principles is critical for an effective design. Perceptual principles. "1. Make displays legible (or audible)". A display's legibility is critical and necessary for designing a usable display. If the characters or objects being displayed cannot be discernible, the operator cannot effectively use them. "2. Avoid absolute judgment limits". Do not  ask the user to determine the level of a variable based on a single sensory variable (e.g., color, size, loudness). These sensory variables can contain many possible levels. "3. Top-down processing". Signals are likely perceived and interpreted by what is expected based on a user's experience. If a signal is presented contrary to the user's expectation, more physical evidence of that signal may need to be presented to assure that it is understood correctly. "4. Redundancy gain". If a signal is presented more than once, it is more likely to be understood correctly. This can be done  by presenting the signal in alternative physical forms (e.g., color and shape, voice and print, etc.), as redundancy does not imply repetition. A traffic light is a good example of redundancy, as color and position are redundant. "5. Similarity causes confusion: Use distinguishable elements". Signals that appear to be similar will likely be confused. The ratio of similar features to different features causes signals to be similar. For example, A423B9 is more similar to A423B8 than 92 is to 93. Unnecessarily similar features should be removed, and dissimilar features should be highlighted. Mental model principles. "6. Principle of pictorial realism . A display should look like the variable that it represents (e.g., the high temperature on a thermometer shown as a higher vertical level). If there are multiple elements, they can be configured in a manner that looks like they would in the represented environment. 7. Principle of the moving part". Moving elements should move in a pattern and direction compatible with the user's mental model of how it actually moves in the system. For example, the moving element on an altimeter should move upward with increasing altitude. Principles based on attention. "8. Minimizing information access cost" or interaction cost . When the user's attention is diverted from one location to another to access necessary information, there is an associated cost in time or effort. A display design should minimize this cost by allowing frequently accessed sources to be located at the nearest possible position. However, adequate legibility should not be sacrificed to reduce this cost. "9. Proximity compatibility principle". Divided attention between two information sources may be necessary for the completion of one task. These sources must be mentally integrated and are defined to have close mental proximity. Information access costs should be low, which can be achieved in  many ways (e.g., proximity, linkage by common colors, patterns, shapes, etc.). However, close display proximity can be harmful by causing too much clutter. "10. Principle of multiple resources". A user can more easily process information across different resources. For example, visual and auditory information can be presented simultaneously rather than presenting all visual or all auditory information. Memory principles. "11. Replace memory with visual information: knowledge in the world". A user should not need to retain important information solely in working memory or retrieve it from long-term memory. A menu, checklist, or another display can aid the user by  easing the use of their memory. However, memory use may sometimes benefit the user by eliminating the need to reference some knowledge globally (e.g., an expert computer operator would rather use direct commands from memory than refer to a manual). The use of knowledge in a user's head and knowledge in the world must be balanced for an effective design. "12. Principle of predictive aiding". Proactive actions are usually more effective than reactive actions. A display should eliminate resource-demanding cognitive tasks and replace them with simpler perceptual tasks to reduce the user's mental resources. This will allow  the user to focus on current conditions and to consider possible future conditions. An example of a predictive aid is a road sign displaying the distance to a certain destination. "13. Principle of consistency". Old habits from other displays will easily transfer to support the processing of new displays if they are designed consistently. A user's long-term memory will trigger actions that are expected to be appropriate. A design must accept this fact and utilize consistency among different displays. Current research. Topics in human–computer interaction include the following: Social computing. Social computing is an interactive and collaborative  behavior considered between technology and people. In recent years, there has been an explosion of social science research focusing on interactions as the unit of analysis, as there are a lot of social computing technologies that include blogs, emails, social networking, quick messaging, and various others. Much of this research draws from psychology, social psychology, and sociology. For example, one study found out that people expected a computer with a man's name to cost more than a machine with a woman's name. Other research finds that individuals perceive their interactions with computers more negatively than humans, despite behaving  the same way towards these machines. Knowledge-driven human–computer interaction. In human and computer interactions, a semantic gap usually exists between human and computer's understandings towards mutual behaviors. Ontology, as a formal representation of domain-specific knowledge, can be used to address this problem by solving the semantic ambiguities between the two parties. Emotions and human–computer interaction. In the interaction of humans and computers, research has studied how computers can detect, process, and react to human emotions to develop emotionally intelligent information systems. Researchers have suggested several 'affect-detection channels'. The potential of telling human emotions in  an automated and digital fashion lies in improvements to the effectiveness of human–computer interaction. The influence of emotions in human–computer interaction has been studied in fields such as financial decision-making using ECG and organizational knowledge sharing using eye-tracking and face readers as affect-detection channels. In these fields, it has been shown that affect-detection channels have the potential to detect human emotions and those information systems can incorporate the data obtained from affect-detection channels to improve decision models. Brain–computer interfaces. A brain–computer interface (BCI), is a direct communication pathway between an enhanced  or wired brain and an external device. BCI differs from neuromodulation in that its allows for bidirectional information flow. BCIs are often directed at researching, mapping, assisting, augmenting, or repairing human cognitive or sensory-motor functions. Factors of change. Traditionally, computer use was modeled as a human–computer dyad in which the two were connected by a narrow explicit communication channel, such as text-based terminals. Much work has been done to make the interaction between a computing system and a human more reflective of the multidimensional nature of everyday communication. Because of potential issues, human–computer interaction shifted focus  beyond the interface to respond to observations as articulated by D. Engelbart: "If ease of use were the only valid criterion, people would stick to tricycles and never try bicycles." How humans interact with computers continues to evolve rapidly. Human–computer interaction is affected by developments in computing. These forces include: Scientific conferences. One of the main conferences for new research in human–computer interaction is the annually held Association for Computing Machinery's (ACM) "Conference on Human Factors in Computing Systems", usually referred to by its short name CHI (pronounced "kai", or "Khai"). CHI is organized by ACM Special  Interest Group on Computer-Human Interaction (SIGCHI). CHI is a large conference, with thousands of attendants, and is quite broad in scope. It is attended by academics, practitioners, and industry people, with company sponsors such as Google, Microsoft, and PayPal. There are also dozens of other smaller, regional, or specialized HCI-related conferences held around the world each year, including: