affordances

After my post about Don Norman's Signifiers, not Affordances article, I had an interesting discussion about the relationship between signifiers, affordances, and features. The importance of signifiers was again reiterated by several people as the key to driving user satisfaction and user capability within an application. Features can only be accessed if the user has an understanding that the feature exists, and signifiers are the agents you as a designer can use to communicate with your users.

I have always been interested in the idea of affordances in user interfaces since I first heard the term. So naturally I was very interested to read an article by Donald Norman - the original researcher to bring the term from psychology to design - about the importance of signifiers instead of affordances.

The term affordances was coined by psychologist J. J. Gibson to explain the possible actions that a specific agent can take on a specific object. Norman brought the idea of affordances, which are realities that exist regardless of the agent's knowledge of them, to design in the guise of "perceivable affordances." For Norman's design work, an unperceived affordance is essentially nothing.

In his article, Norman espouses the idea that designers should forget about affordances and focus on the signs that affordances exist; these he calls signifiers. His reasoning is straightforward - it's not the fact that this user interface widget can be dragged that is important to design, but the signifier that indicates to the user that the item can be dragged.