Interaction design (IxD) is the study of devices with which a user can interact, in particular computer users. The practice typically centers on “embedding information technology into the ambient social complexities of the physical world.” It can also apply to other types of non-electronic products and services, and even organizations. Interaction design defines the behavior (the “interaction”) of an artifact or system in response to its users. Malcolm McCullough has written, “As a consequence of pervasive computing, interaction design is poised to become one of the main liberal arts of the twenty-first century.”
Interactivity, however, is not limited to technological systems. People have been interacting with each other as long as humans have been a species. Therefore, interaction design can be applied to the development of all solutions (or offerings), such as services and events. Those who design these offerings have, typically, performed interaction design inherently without naming it as such.