What you see is not always what’s there. There are many occasions in which people are blind to things that are present in their environment. Inattentional blindness is known as not being able to see things that are actually present. This phenomenon occurs due in to part to a lack of a frame of reference from which the object can be perceived. Another explanation for this is mental focus; one may be focusing on an object so intently that a mental distraction occurs, leaving objects ignored. Our brains cannot focus on every detail at once, but this is not necessarily a terrible thing. Though we cannot focus on every detail in our environment, we are able to focus intently on particular tasks and objects, increasing our efficiency and assisting in our survival; we know how to segregate the important from the unimportant. Of course there are some funny moments that occur because of our inattentional blindness:

I can empathize with all of these people that were victims to the swap. I can imagine myself in their situation, especially considering that I am the type of person to devote my full attention to something I find important. I can see myself talking to a gentleman or lady that had just asked me for directions, and as I am looking down on the map, my frame of reference changes. This, coinciding with my devoted concentration to the task at hand (reading a map isn’t that easy) allows the man or lady to make a swap without me noticing, allowing for a funny (read: completely embarrassing) television moment. Change blindness and inattentional blindness are two very similar phenomena and can often go hand in hand. What makes them differ is the idea that change blindness can occur from some type of obstruction of visual perception (such as a saccade). The end result is similar, a lack of perception of an object that is present.