By now all designers know it: to create a good product you have to aim for Affordance, that is, the object’s ability to suggest the set of actions that can be performed with it.

But what actions can a person perform with an object? Obviously only those they can perceive!
Users act only when they can see the properties of the object that suggest the action. Sight is a sort of “activator“: the user maps the object and plans the behavior to be emitted.
Thanks to eye tracking technology, we can see through the eyes of the end user of a product which Actionable Properties are perceived and which instead are ignored.
End users do not always behave as the designer expects.