Attention and Inattention
A similar example is the cocktail party effect. People are often unaware of conversations taking place outside of their particular group at a party. However, if someone in another group casually mentions their name, they immediately become aware of it. The cocktail party effect is a form of selective attention. Individuals attend easily to their own name, as it is a familiar stimulus. Therefore, they will filter out other stimuli upon hearing their name.
Inattentional Blindness and Change Blindness
Change blindness is the failure to notice a change in a stimulus event. In 1998, cognitive psychologists Daniel Simons and Daniel Levin conducted a study in which an experimenter held a map and asked a random pedestrian for directions. As the pedestrian and experimenter were looking down at the map, two people walked in between them holding a large wooden door that blocked their view of each other. During this interruption, the experimenter switched places with one of the door carriers. This second person looked and sounded nothing like the experimenter. However, nearly half the pedestrians failed to notice they were talking to a different person.