Change blindness
Change blindness is a phenomenon that applies to how humans are often "blind" to even large changes in the environment.
You would notice if the person in front of you changed into another person—or so you'd hope. This was experimented on, and produced surprising results. In the research, participants were approached by a stranger that asked for directions. The stranger was blocked from the participants' view by a large object. The stranger was then replaced with another person of the same sex and race. A whopping half of the people giving directions never noticed that they were talking to a different person![1]
We normally do not process the facial features of faces or clothing in strangers. Since we do not process them, they are not encoded into memory. Why would we need to recall such information in the first place?[2]
