The stereotype is that younger people will not answer the door, and the polling supports it as a gradient rather than a cliff: 59% of Americans 65 and over would open the door to an unexpected stranger, and the share falls steadily with each younger age band. What is more interesting is that the reluctance does not extend to neighbours. Majorities are willing to knock on a next-door neighbour's door to borrow something (53%) or to ask for help in an emergency (69%), and willingness to borrow is no higher among older people than younger ones. So the reticence is about unidentified callers, not about neighbourliness in general. The knock itself is also still very much alive among the young in its least useful form: 40% of Gen Z say they have played ding-dong ditch (knocking or ringing and running), which is a slightly higher share than Gen X. People have not stopped knocking on doors. They have stopped answering them.