Been thinking a lot about social aspects of security systems recently, and cultures and contexts where its common to have a nightwatchman. Your neighbourhood has a nightwatchman right?

The patrol happens every hour between midnight and dawn around the house and/or neighbourhood with the completion of the check marked by a simple auditory signal: clapping two pieces of wood together; a low whistle. When you are lying there jet lagged in the dark the signal is one of the things that keeps you awake the first few nights in a new locale. By the third night it sends you to sleep.

Three of our field study accommodations that included the services of a nightwatchman: Medan, Indonesia; New Delhi, India; and our upscale apartment in Northern Tehran, Iran.

Photo from Tehran.