Sonya Lacey ⬤ Eveningness

In chronobiology, "eveningness" names a biologically influenced tendency toward later hours, not a habit or lifestyle choice. It sits at one end of a spectrum, opposite "morningness." Most people fall somewhere in between, their rhythms shaped by genetics and age. Eveningness is rarely treated as neutral variation. Schools start early. Workplaces expect morning presence. The evening-oriented are told to adjust. Researchers call the result "social jet lag": chronic misalignment between the internal clock and imposed schedules. The health risks often attributed to eveningness-mood disorders, metabolic issues-appear to come not from the chronotype itself, but from being forced out of sync. The problem is mismatch, not the body. Bodies stay synchronised to the 24-hour day through cues. Light is the most powerful, but sound, temperature, routine, and language also carry temporal information. A greeting like "good morning" is a timestamp. Traffic rises and falls with rush hour. We track these signals continuously, adjusting sleep and alertness to stay aligned with the world. Time Isolation Units-environments developed for circadian research—remove or control these cues, so that researchers can observe what happens when the outside world stops providing timestamps. Sleep drifts. Perception shifts. The body settles into its own rhythm, slowly rotating out of phase. The walls of such units are layered with materials that block light, dampen sound, and shield against stray signals-copper among them, forming a barrier that stops information from passing through. What such research reveals is that "day" is not a given. It is produced-by light, by architecture, by protocol. Time is something transmitted through channels and made believable through design. The same knowledge can support care and wellbeing, or serve optimisation: fitting workers to night shifts, extending the productive day.