After reading and understanding this article I have learned new meanings to the word affordance. When describing the meaning of the word, Gibson and Norman both related scientific meaning into visual aspects. Affordances have a lot to do with the way one perceives things and can be easily and successfully related to the world of design. It seems that Gibson and Norman knew that an affordance was the possibility of making an action. In design it is important to make affordances easy to comprehend. It makes sense that if a design aspect such as an interface it difficult to use then it will not be successful. If a designer improves the affordances in the design, it will be easier to access and more appealing to the users. This is not to say that the designer should make everything simplier, but makes the affordances easier to comprehend.
It made sense when the writer stated that you have to test something in order to make a direct affordance. If only an assumption is made the affordance may not exsist. The hidden wall that was given as an example proves this. If you do not test the door to see if it opens than you do not have a direct affordance. If it is only assummed that a door is there, but do not test it, there is no valid affordance to be made.