Human-Computer Interaction (HCI) is a field of computer science that concerns the design, evaluation, and implementation of interactive computing systems for human use and with humans in mind. These interactive systems include software applications as well as hardware devices such as personal digital assistants, mobile phones, or specialized medical equipment. It involves not only how humans interact with computers, but also how they interact with any electronic device that can respond to a person's action.

The study of human-computer interactions (HCI) is a multidisciplinary field of study that focuses on the design of computer technology and, in particular, the interaction between humans (the users) and computers. While HCI was originally focused on computers, it has since expanded to embrace almost all types of information technology development. HCI is now a broad discipline that needs to be addressed from many different perspectives, including psychology, computer science, and cognitive science.

In short: HCI is the design of digital technology that people can use easily and efficiently in their specific situations.

This definition makes HCI a relatively new field of study when compared with other fields in computer science such as artificial intelligence or human-machine interaction. However, it is very broad in its scope and encompasses not only the purely practical aspects of designing for ease of use but also scientific research into what works best for humans. For example, an HCI researcher might investigate whether users are more likely to remember information presented using red text rather than blue—a psychological question about how humans perceive color which falls squarely into the realm of cognitive science.

A design that fails to consider what is important for users can be difficult or impossible to use, and an HCI researcher might subject such a design to scientific evaluation using methods like focus groups, surveys, and controlled experiments with human subjects. The findings from such studies inform the designer as much as possible about how real people use technology in their respective contexts; this allows designers to make informed tradeoffs between ease-of-use and other factors such as aesthetics or security.

The UX Value of HCI and Its Related Realms

A foundation in HCI provides UX professionals with the knowledge needed to implement effective user experiences for software, systems, and devices. Understanding the core concepts of HCI facilitates insight into how humans can best interact with computers in general, allowing for more intuitive solutions to design challenges.

Despite that, there are some distinctions between HCI and UX design. HCI practitioners are more academically inclined. They engage in academic research and the creation of empirical knowledge regarding users. In contrast, UX designers tend to be industry-focused and engaged in the development of goods or services, such as smartphone apps and websites.

HCI is related to several other disciplines in the sense that its research informs the practices of these disciplines. In particular, it shares a strong relationship with human-computer interaction (HCI), which focuses on how people interact with computers and computer-based systems. Although some people use the terms HCI and user experience design interchangeably or even consider them to be the same thing, others consider them distinct disciplines with overlapping skills and knowledge.