Field note. Subterranean chamber, low light, fog dispensed at intervals from concealed vents. The specimens have gathered voluntarily.
A machine produces a single percussive impact, repeated at a fixed interval, roughly one hundred and thirty times per unit. It does not vary. It does not resolve. The humans have chosen this. They arrived after their star had set, will not leave before it rises, and have arranged their bodies into a dense field of oscillation, each one flexing at the knee in time with the impact, eyes half-closed, faces emptied of the strain they wear in daylight.
I searched for the leader. There is none. I searched for the message being transmitted. There is none. The sound carries no words, no instruction, no warning. It is pure interval, and they follow it with the devotion I have previously observed only in migratory species answering a signal they cannot name.
Correction to my earlier report. I classified the boredom of this species as a defect. Here the boredom appears deliberate, induced, prized. They have engineered a room in which nothing happens for eight hours and have paid to be inside it. When the machine briefly ceases its impact, a single high tone rising toward some threshold, the field goes still, breath held, all two thousand of them waiting. Then the impact returns and the field convulses as one organism.
They are not dancing away from something. They are synchronizing. Two thousand separate nervous systems, unrelated by blood, briefly beating on the same interval, in the dark, where no one can see whose face is whose.
I do not understand the emotional function. I have logged it anyway. The specimen appears least lonely at the exact moment it can no longer be told apart.