Every night spent in an unfamiliar place is, in some quiet way, a negotiation between the modern self and an ancient brain that has not yet learned to trust the new. Researchers call it the first-night effect — a measurable, evolutionary inheritance in which the sleeping mind keeps partial watch in unknown surroundings, costing most people twenty to thirty minutes of sleep and considerable depth of rest. It is not anxiety exactly, nor poor judgment about comfort; it is the brain doing what brains have always done when the territory is uncharted. The good news, as sleep science confirms, is tha