Inattentional blindness is defined as the failure to detect stimuli that are in plain sight when our attention is focused elsewhere. It when one's mental representation of the outside world is limited to only a few elements, and one attends to only the "interesting" parts of the environment. The remarkable thing about this phenomenon is that things that may seem so clear and obvious in a normal situation may be hidden or oblivious to people who are distracted by something else. I find this quite fascinating. There are many experiments and studies that have been done on this concept, and there are several articles and videos to show it. One example that I find very interesting is the youtube video of the two young men who change roles when the innocent, oblivious person is distracted. The video shows one of the two men standing behind a counter in an office, when a customer walks in. The man hands the customer a consent sheet to fill out, and as the customer finishes the sheet and hands it to the man, the man ducks down to put it away underneath the counter. Instead of the same man standing up after the consent sheet is put away, the other man stands up instead. The phenomenon in the study is that every customer that was finished filling out the sheet never noticed the change in the man behind the counter. This is a great example of inattentional blindness, because it shows that although we may seem to always know what is going on in the environment around us, we may be distracted when our attention is focused somewhere else and miss things that are in plain sight. I can think of several examples in my life when I have had inattentional blindness happen to me.