Human–Computer Interaction and Usability/Accessibility

The most powerful software fails if people cannot use it comfortably. Human–Computer Interaction (HCI) is the field that studies how people interact with computers and how to design interfaces that are effective, efficient, and satisfying to use. HCI draws on computer science, psychology, and design, and its central concern is to fit the system to the human rather than forcing the human to adapt to the system.

Usability

Usability describes how easy and pleasant a system is to use. A usable system lets people accomplish their goals accurately, quickly, and with a sense of satisfaction. Usability is often broken into qualities such as learnability (how easily a new user gets started), efficiency (how quickly an experienced user works), memorability (how easily an occasional user returns with