Circadian Timing and Time Perception in Healthy Adults

Recruiting now · Not applicable

Conditions studied: Circadian Rhythm, Time Perception

In brief

This study examines how a person's natural daily rhythm ("chronotype") affects the way time is experienced and judged. Healthy Danish-speaking adults (23-45 years) who are clearly morning-type or evening-type will complete two lab sessions in a crossover design: one at their preferred time of day (e.g., morning for morning-types) and one at the opposite time (misaligned). In each session, participants do brief computerized tasks that measure time estimation/production, vigilance (psychomotor vigilance task), decision-making, and responses to social information, plus simple color-vision tasks. Short questionnaires about sleepiness, mood, fatigue, and the subjective "passage of time" are collected before, during, and after testing. A subset will wear a wrist actigraphy device for one week beforehand to characterize sleep-wake patterns. Testing is conducted under standardized lab conditions with scheduled breaks. The main goal is to determine whether time judgments and vigilance are less accurate during the misaligned session and whether decision-making and social responses also vary with circadian timing. Risks are minimal and mainly relate to temporary tiredness when tested at a non-preferred time; participants may stop at any time. Participation is voluntary. Data are pseudonymized and handled under GDPR. Participants receive DKK 300 after completing both sessions (pro-rated if they withdraw early). Results will be published regardless of outcome, and de-identified data/code will be shared after publication.This study examines how a person's natural daily rhythm ("chronotype") affects the way time is experienced and judged. Healthy Danish-speaking adults (23-45 years) who are clearly morning-type or evening-type will complete two lab sessions in a crossover design: one at their preferred time of day (e.g., morning for morning-types) and one at the opposite time (misaligned). In each session, participants do brief computerized tasks that measure time estimation/production, vigilance (psychomotor vigilance task), decision-making, and responses to social information, plus simple color-vision tasks. Short questionnaires about sleepiness, mood, fatigue, and the subjective "passage of time" are collected before, during, and after testing. A subset will wear a wrist actigraphy device for one week beforehand to characterize sleep-wake patterns. Testing is conducted under standardized lab conditions with scheduled breaks. The main goal is to determine whether time judgments and vigilance are less accurate during the misaligned session and whether decision-making and social responses also vary with circadian timing. Risks are minimal and mainly relate to temporary tiredness when tested at a non-preferred time; participants may stop at any time. Participation is voluntary. Data are pseudonymized and handled under GDPR. Participants receive DKK 300 after completing both sessions (pro-rated if they withdraw early). Results will be published regardless of outcome, and de-identified data/code will be shared after publication.

Key facts

Study ID: NCT07292597
Run by: University of Aarhus
People needed: 128
Starts: 2025-10-25
Expected to finish: 2027-06-30
Last updated by the study team: 2025-12-22

Who can join

Age: 23 and older, up to 45. Sex: any. Healthy volunteers: accepted.

You may qualify if…

Aged 23 to 45 years
Able to understand and communicate in Danish
Completed at least upper secondary education (e.g., gymnasium)
Categorized as either a Morning Type (MT) or Evening Type (ET) based on standardized chronotype assessments:
Munich Chronotype Questionnaire (MCTQ):
MT: sleep midpoint on free days (MSFsc) ≤ 03:00
ET: sleep midpoint on free days (MSFsc) ≥ 05:00
Morningness-Eveningness Questionnaire (MEQ):
One of four defined chronotype categories (definitely morning, moderately morning, moderately evening, definitely evening).

You may not qualify if…

Current engagement in shift work, rotating schedules, or other forms of irregular sleep-wake timing
Diagnosis of any neurological, psychiatric, or sleep-related disorder (e.g., insomnia, narcolepsy, sleep apnea)
Use of medications that affect sleep, alertness, or circadian functioning (e.g., melatonin, stimulants, antidepressants)
International travel across time zones within the four weeks preceding study participation
Are classified as having an intermediate chronotype based on validated chronotype assessments (MCTQ or MEQ), as this group does not provide the necessary contrast to evaluate circadian alignment effects.

Where it is running

Cognition and Behavior Lab — Aarhus, Denmark (enrolling)

Full record on ClinicalTrials.gov

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