Human–computer interaction (HCI) is the process through which people operate and engage with computer systems. Research in HCI covers the design and the use of computer technology, which focuses on the interfaces between people (users) and computers. HCI researchers observe how people interact with computers and design technologies that allow humans to interact with computers in new ways. These include visual, auditory, and tactile (haptic) feedback systems, which serve as channels for interaction in both traditional interfaces and mobile computing contexts. A device that allows interaction between human and a computer is known as a "human–computer interface". For example: the design of a smartphone's touchscreen interface involves HCI principles to ensure that icons are large enough to be tapped easily, and that gestures (like swiping or pinching) are supported.
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.
The term was popularized by Stuart Card, Allen Newell, and Thomas P. Moran in their seminal 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.
Definition 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, web browsers, handheld computers, and computer kiosks make use of the prevalent graphical user interfaces (GUIs) of today, while command-line interfaces (CLIs) were the main way to use a computer and are now used mostly by system administrators and programmers. Voice user interfaces (VUIs) are used for speech recognition and synthesizing systems, and the emerging multi-modal GUIs allow humans to engage with embodied character agents in a way that cannot be achieved with other interface paradigms.
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". A key aspect of HCI is user satisfaction, also referred to as 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."
HCI ensures that humans can safely and efficiently interact with complex technologies in fields like aviation and healthcare. Due to the multidisciplinary nature of HCI, people with different backgrounds contribute to its success.
Human–computer interface
A human–computer interface can be described as the interface of communication between a human user and a 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:
Feedback: Loops through the interface that evaluate, moderate, and confirm processes as they pass from the human through the interface to the computer and back. Fit: This matches the computer design, the user, and the task to optimize the human resources needed to accomplish the task. Visual-based HCI Facial expression analysis: This area focuses on visually recognizing and analyzing emotions through facial expressions. Body movement tracking (large-scale): Researchers in this area concentrate on tracking and analyzing large-scale body movements. Gesture recognition: Gesture recognition involves identifying and interpreting gestures made by users, often used for direct interaction with computers in command and action scenarios. Gaze detection (eye-movement tracking): Gaze detection involves tracking the movement of a user's eyes and is primarily used to better understand the user's attention, intent, or focus in context-sensitive situations. While the specific goals of each area vary based on applications, they collectively contribute to enhancing human-computer interaction. Notably, visual approaches have been explored as alternatives or aids to other types of interactions, such as audio- and sensor-based methods. For example, lip reading or lip movement tracking has proven influential in correcting speech recognition errors. Audio-based HCI Audio-based interaction in human-computer interaction (HCI) is a crucial field focused on processing information acquired through various audio signals. While the nature of audio signals may be less diverse compared to visual signals, the information they provide can be highly reliable, valuable, and sometimes uniquely informative. The research areas within this domain include: Speech recognition: This area centers on the recognition and interpretation of spoken language. Speaker recognition: Researchers in this area concentrate on identifying and distinguishing different speakers. Auditory emotion analysis: Efforts have been made to incorporate human emotions into intelligent human-computer interaction by analyzing emotional cues in audio signals. Human-made noise/sign detections: This involves recognizing typical human auditory signs like sighs, gasps, laughs, cries, etc., which contribute to emotion analysis and the design of more intelligent HCI systems. Musical interaction: A relatively new area in HCI, it involves generating and interacting with music, with applications in the art industry. This field is studied in both audio- and visual-based HCI systems. Sensor-based HCIThis section encompasses a diverse range of areas with broad applications, all of which involve the use of physical sensors to facilitate interaction between users and machines. These sensors can range from basic to highly sophisticated. The specific areas include: Pen-based interaction: Particularly relevant in mobile devices, focusing on pen gestures and handwriting recognition. Mouse & keyboard: Well-established input devices, commonly used in computing. Joysticks: Another established input device for interactive control, commonly used in gaming and simulations. Motion-tracking sensors and digitizers: Cutting-edge technology that has revolutionized industries like film, animation, art, and gaming. These sensors, in forms like wearable cloth or joint sensors, enable more immersive interactions between computers and reality. Haptic sensors: Particularly significant in applications related to robotics and virtual reality, providing feedback based on touch. They play a crucial role in enhancing sensitivity and awareness in humanoid robots, as well as in medical surgery applications. Pressure sensors: Also important in robotics, virtual reality, and medical applications, providing information based on pressure exerted on a surface. Taste/smell sensors: Although less popular compared to other areas, research has been conducted in the field of sensors for taste and smell. These sensors vary in their level of maturity, with some being well-established and others representing cutting-edge technologies.
Goals for computers Human–computer interaction involves the ways in which humans 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:
Methods for designing new computer interfaces, thereby optimizing a design for a desired property such as learnability, ease of finding, and efficiency of use. Methods for implementing interfaces, e.g., by means of software libraries. Methods for evaluating and comparing interfaces with respect to their usability and other desirable properties. Methods for studying human–computer use and its sociocultural implications more broadly. Methods for determining whether or not the user is human or computer. Models and theories of human–computer use as well as conceptual frameworks for the design of computer interfaces, such as cognitivist user models, Activity Theory, or ethnomethodological accounts of human–computer use. Perspectives that critically reflect upon the values that underlie computational design, computer use, and HCI research practice.
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.
Poorly designed user 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, some 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.
Design
Principles
The following experimental design principles are considered, when evaluating a current user interface, or designing a new user interface: Early focus is placed on the user(s) and task(s): How many users are needed to perform the task(s) is established and who the appropriate users should be is determined (someone who has never used the interface, and will not use the interface in the future, is most likely not a valid user). In addition, the task(s) the users will be performing and how often the task(s) need to be performed is defined. Empirical measurement: the interface is tested with real users who come in contact with the interface daily. The results can vary with the performance level of the user and the typical human–computer interaction may not always be represented. Quantitative usability specifics, such as the number of users performing the task(s), the time to complete the task(s), and the number of errors made during the task(s) are determined. Iterative design: After determining what users, tasks, and empirical measurements to include, the following iterative design steps are performed: Design the user interface Test Analyze results Repeat The iterative design process is repeated until a sensible, user-friendly interface is created.
Methodologies