Interactivity

In the fields of information science, communication, and industrial design, there is debate over the meaning of interactivity. In the "contingency view" of interactivity, there are three levels:
 * 1) Noninteractive, when a message is not related to previous messages;
 * 2) Reactive, when a message is related only to one immediately previous message; and
 * 3) Interactive, when a message is related to a number of previous messages and to the relationship between them.

Human to human communication
Human communication is the basic example of interactive communication which involves two different processes; human to human interactivity and human to computer interactivity. Human-Human interactivity is the communication between people.

On the other hand, human to computer communication is the way that people communicate with new media. According to Rada Roy, the "Human Computer interaction model might consists of 4 main components which consist of HUMAN, COMPUTER, TASK ENVIRONMENT and MACHINE ENVIRONMENT. The two basic flows of information and control are assumed. The communication between people and computers; one must understand something about both and about the tasks which people perform with computers. A general model of human - computer interface emphasizes the flow of information and control at the human computer interface." Human to Human interactivity consists of many conceptualizations which are based on anthropomorphic definitions. For example, complex systems that detect and react to human behavior are sometimes called interactive. Under this perspective, interaction includes responses to human physical manipulation like movement, body language, and/or changes in mental states.

Human to artifact communication
In the context of communication between a human and an artifact, interactivity refers to the artifact’s interactive behaviour as experienced by the human user. This is different from other aspects of the artifact such as its visual appearance, its internal working, and the meaning of the signs it might mediate. For example, the interactivity of an iPod is not its physical shape and colour (its so-called "design"), its ability to play music, or its storage capacity—it is the behaviour of its user interface as experienced by its user. This includes the way you move your finger on its input wheel, the way this allows you to select a tune in the playlist, and the way you control the volume.

An artifact’s interactivity is best perceived through use. A bystander can imagine how it would be like to use an artifact by watching others use it, but it is only through actual use that its interactivity is fully experienced and "felt". This is due to the kinesthetic nature of the interactive experience. It is similar to the difference between watching someone drive a car and actually driving it. It is only through the driving that you can experience and "feel" how this car differs from others.

New Media academic Vincent Maher defines interactivity as "the relation constituted by a symbolic interface between its referential, objective functionality and the subject."

Computing science
The term "look and feel" is often used to refer to the specifics of a computer system's user interface. Using this metaphor, the "look" refers to its visual design, while the "feel" refers to its interactivity. Indirectly this can be regarded as an informal definition of interactivity.

A more detailed discussion of how interactivity has been conceptualized in the human-computer interaction literature, and how the phenomenology of the French philosopher Merleau-Ponty can shed light on the user experience, see (Svanaes 2000).

In computer science, interactive refers to software which accepts and responds to input from humans—for example, data or commands. Interactive software includes most popular programs, such as word processors or spreadsheet applications. By comparison, noninteractive programs operate without human contact; examples of these include compilers and batch processing applications. If the response is complex enough it is said that the system is conducting social interaction and some systems try to achieve this through the implementation of social interfaces.

Also, there is the notion of kinds of user interaction, like the Rich UI.

Creating Interactivity
Web page authors can integrate JavaScript coding to create interactive web pages. Sliders, date pickers, drag and dropping are just some of the many enhancements that can be provided.

Various authoring tools are available for creating various kinds of interactivities. Some of the most common platforms for creating interactivities include Adobe Flash and the recently released Microsoft Silverlight. The most commonly used authoring tools for creating interactivities include Harbinger's Elicitus and Articulate's Engage. eLearning makes use of a concept called an interaction model. Using an interaction model, any person can create interactivities in a very short period of time. Some tools like Harbinger's Raptivity come with readymade interaction models that can be customized easily without any programming.

Some of the interaction models presented with authoring tools fall under various categories like games, puzzles, simulation tools, presentation tools, etc., which can be completely customized.