IxD Principles


The answers should be given by the design, without any need for words or symbols, certainly without any need for trial and error.” Don Norman

The answers Don Norman addresses are PERCEIVED through affordances. As he describes it, these affordances are “primarily those fundamental properties that determine just how the thing could possibly be used [, and] provide strong clues to the operations of things”. Thus, affordances allow the transition from the first principle to the second (Perceivability to PREDICTABILITY). It’s thanks to these visible assets in products –affordances–, that people are able to interact (operate and manipulate). Given to FEEDBACK (the third principle) people can understand and know how to overcome error (machine’s) and mistakes (people’s). Through repeated interaction, people get to LEARN how to use a product, and thanks to CONSISTENT standard practices among similar products, transfer its usage from one type of product to another.

Besides use standards and best practices, Don Norman addresses the importance of affection in the design process. He points the nuances between negative and positive affection, and draws the importance of creating good human-centered design whenever addressing stressful situations. In the end, he emphasizes that “[t]rue beauty in a product has to be more than skin deep, more than a façade. To be truly beautiful, wondrous, and pleasurable, the product has to fulfill a useful function, work well, and be usable and understandable.