Human-computer interface(HCI) The means of communication between a human user and a computer system, referring in particular to the use of input/output devices with supporting software. Devices of increasing sophistication are becoming available to mediate the human-computer interaction. These include graphics devices, touch sensitive devices, and voice-input devices. They have to be configured in a way that will facilitate an efficient and desirable interaction between a person and the computer. Artificial intelligence techniques of knowledge representation may be used to model the user of a computer system, and so offer the opportunity to give personalized advice on its use. The design of the machine interface may incorporate expert-system techniques to offer powerful knowledge-based computing to the user.
HCI is a branch of the science of ergonomics, and is concerned especially with the relationship between workstations and their operators. The aim is to develop acceptable standards for such aspects as display resolution, use of color, and navigation around an application.
The terms human-system interface(HSI), human-machine interface(HMI), and man- machine interface(MMI) are all used as synonyms.
Humans interact with computers in many ways; the interface between humans and computers is crucial to facilitate this interaction. 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 been in quality of interaction, and in different branching in its history. Instead of designing regular interfaces, the different research branches have had a different focus on the concepts of multimodality rather than unimodality, intelligent adaptive interfaces rather than command/action based ones, and finally active rather than passive interfaces.
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 instrument or throttle quadrant layouts: even though the new designs were proposed be superior in basic human-machine interaction, pilots had already ingrained the “standard” layout and thus the conceptually good idea actually had undesirable results.
The interfaces and processes that make up human-computer interaction are understood and advanced through a variety of methods. At one level, this interaction can be characterized by the capabilities and processes of the human and the computer to accept input, process that input, and generate output. The computer capabilities include the hardware (input and output devices) such as the monitor, mouse, keyboard, and Internet connection. These devices reflect contributions from computer science and engineering, whereas the human capabilities, both mental and physical, are understood through cognitive science and ergonomics. At another level, the interaction between the computer and the human consists of user interface software which governs the meanings of the inputs and outputs for the computer, as well as the corresponding rules and expectations that the user applies to generate meaningful actions. The user’s internal model of the interaction is supported by visual cues in the interface and designed in accordance with principles of human factors. At a higher level, this interaction includes the context of goals, motivations, and other people and resources that determine what the person is doing. Understanding the process at this level requires insights from social and organizational sciences. See Human-factors engineering
Advances in computer science have significantly increased the processing power of computers while decreasing their size. These advances have provided the underlying technology for creating a wider variety of human-computer interactions. For example, streaming audio and video over the Internet, now common, would not be possible without the increased processing power and network connectivity of computers. These technological developments were influenced by the discovery of useful applications in human-computer interaction. Increasingly sophisticated software has become available to address input through natural speech and immersive environments, providing a virtual reality experience. See Virtual reality
Developing human-computer interactions involves design on both sides of the interaction. On the technology side, the designer must have a thorough understanding of the available hardware and software components and tools. On the human side, the designer must have a good understanding of how humans learn and work with computers, including envisioning new modes of working. The designer’s task is to create effective, efficient, and satisfying interactions by balancing factors such as cost, benefits, standards, and the environmental constraints in which the interaction will take place.
Modern prototyping tools allow for the use of an iterative development model where a representative portion of the interface is designed and implemented with each iteration. Feedback from testers is used to enhance the design with each iteration. The final design consists of many elements: the resulting artifacts for use by the target population, as well as supporting elements such as an analysis of needs and tasks, descriptions of the dialog rules and users’ conceptual models, expected scenarios of use, and the designer’s rationale and reflections from the development process.