Word: Change Blindness

Definition: A perceptual phenomenon in which an observer does not notice the introduction of visual changes to an existing image.

Reference: Think about the games you played as a kid that flashed the same image twice but the second time something was different and you had to figure out what that was. This is surprisingly difficult! It is difficult because there is an interruption in our visual perception and because of the speed in which this happens, our eyes have a difficult time fixating on those changes and interpreting them.

Thoughts: Now think about a time you submitted a form only to see an error message. Then you have to identify which form field the error occurred in. Why is it so hard to find the form field with the small red "x" next to it? Change blindness, that's why! The subtle change between the form pages is not enough to easily identify the problem and therefore we become a frustrated user as we search for the erred field. This is just one of many examples of how change blindness can effect user experience. It is important to think about this while designing subtle interactions.