Interaction design (also called user interface design)

Interaction design concerns itself with the functionality and behaviour of a physical or digital product. The user acts and the product reacts in an understandable and expected manner.

The interaction designer needs visual skills in order to express the principles of feedback, affordance, focus of attention, simplicity and self-evidency. They have an understanding of the technologies that they are designing for, and can use authoring languages or tools, such as DHTML or Director, to demonstrate timing, information presentation and spatial relationships.

In products, interaction designers think about both the physical and on-screen aspects of the interaction. In websites, they are involved in the application-oriented and functional aspects, getting down to the details of how inputs and outputs work. They also think about broader interactions or events, and visualise this through usage scenarios and storyboards.