Study of Morning and Evening Types Effects on Time Perception and Cognition at Different Times Across Cultures

What this Trial Is About

Researchers are studying how a persons chronotype, whether they are a morning-type or evening-type, affects their perception of time depending on the time of day they are tested. The study examines if being tested at a preferred or non-preferred time influences how accurately people perceive time, and whether these effects are consistent across different cultures and locations. The trial involves healthy adults aged 18 to 55 classified clearly as morning or evening types, excluding intermediate chronotypes. Participants complete two test sessions that involve a range of perception and cognition tasks. One session occurs early in the morning around 0800 and the other late in the evening around 2200. Both sessions include identical tests on time perception, sleepiness, mood, color perception with and without blue-blocking glasses, and perceptual decision-making, arranged in counterbalanced order. The study is conducted at three sites across different cultures to assess generalizability. During the study, participants are assessed twice within about two weeks, completing tasks measuring time-perception bias, timing precision, subjective passage of time, sleepiness, mood, and color perception. Researchers use questionnaires, vigilance tasks, and color vision tests to evaluate outcomes. The primary measure is the accuracy of time perception, with secondary measures including other cognitive and sensory assessments. The study also monitors participant adherence and collects sleep diaries before testing to support analysis.

Chronotype Alignment and Time Perception