Interaction design aims to define and facilitate interaction between human beings by means of a product or a service. It focuses on the possibilities to create and encourage behavior facilitating an exchange between people.

We can therefore see interaction design on two levels:
 . either between a user and a system;
 . or between different users, in which case we speak about human interaction or “social interaction”.

Interaction design focuses on human behavior.

It heavily leans on the material gathered during the observation phase. In general these observations are conducted by human factors specialists.

In the conceptual phase interaction design aims at pushing back the limits of known cognitive systems and to offer an optimized user experience.

Interaction design is not necessarily related to technological aspects, contrary to user interface design. It can touch upon a whole variety of means and carriers, not necessarily information technology.

During the conceptual phase an interaction designer works with such notions as:

_mental model (a person’s representation of a system or an environment);

_metaphors;

_“mapping” (availability of system control elements and their impact);

_real or perceived affordance of an object (the object’s capacity to suggest its own function);

_censes (sight, touch, sound, smell...);

_user environment (immersion, augmented reality, virtual worlds, tactile interfaces...)

True interactivity is not about clicking on icons or downloading files, it’s about encouraging communication.

Edwin Schlossberg,
2002