Assuming the 120 seconds is accurate, I wonder what factors make that the sweet spot? Short enough to average over alts, but long enough to have some convincing short-range correlation in the convos?

(francophones may be interested in the following story from the minitel days, before queue-based averaging of the « animatrices » : https://archive.wikiwix.com/cache/index2.php?url=http%3A%2F%... )