Fact
Half of people miss a person swapping places mid-conversation
A stranger asked you for directions. Then a different stranger finished the conversation.
In a classic experiment, an experimenter stopped pedestrians to ask for directions. Two people carrying a door then walked between them, and a different person emerged to continue the conversation. Around half of participants never noticed the switch. The effect is called change blindness, and it shows how little of a scene we actually hold in mind.