Chronotype Alignment and Time Perception
Trial statusRecruiting
Trial phaseNot applicable
Trial typeInterventional
Biological sexAll
Age18-55
SponsorThe Hong Kong Polytechnic University
About this trial
People differ in chronotype - whether they function best in the morning ("larks") or the evening ("owls"). This study asks whether the match or mismatch between a person's chronotype and the time of day at which they are tested changes how they perceive time.
Healthy morning-type and evening-type adults at three sites (Aarhus, Denmark; Changzhou, China; and Hong Kong) complete the same battery of perception and cognition tasks twice - once in the early morning (about 08:00) and once late in the evening (about 22:00), in counterbalanced order. The primary outcome is the accuracy (signed bias) of time-perception judgements; the key comparison is the interaction between chronotype and time of day (the "synchrony effect").
Secondary measures include timing precision, the subjective passage of time, sleepiness, mood, colour perception (with and without blue-blocking glasses) and perceptual decision-making. By testing the same protocol across three cultures and latitudes, the study examines whether circadian match/mismatch effects on temporal cognition generalise across populations.
Eligibility criteria
This trial accepts healthy volunteersQualifiers
Healthy adult, 18-40 years
Clear morning-type or evening-type on the Morningness-Eveningness Questionnaire (MEQ-SA); intermediate types excluded (state exact cut-offs, e.g. evening-type 41 or below, morning-type 59 or above)
Normal or corrected-to-normal visual acuity
Normal colour vision (e.g. Ishihara screening)
Disqualifiers
Intermediate chronotype (MEQ in the middle band)
Night or rotating shift work in the past 3 months, or recent trans-meridian travel (more than 2 time zones in the past 4 weeks)
Diagnosed sleep disorder (e.g. insomnia, sleep apnoea)
Current psychiatric or neurological disorder
Trial design
Design model
Crossover
Treatments tested in this trial
Morning test session (about 08:00)
BehavioralFull perception and cognition battery administered shortly after habitual wake (about 08:00): time-perception tasks (interval production/estimation, duration discrimination, passage-of-time judgement), state measures (sleepiness, mood, arousal), colour tasks, a perceptual conformity task, and a vigilance task.
Evening test session (about 22:00)
BehavioralThe identical battery administered late in the evening (about 22:00), enabling within-participant comparison of the same measures at the two times of day.
Treatment groups
240 Participants
are divided into 2 treatment groupsGroup A: Morning-first sequenceExperimental treatment 2 interventions
Group B: Evening-first sequenceExperimental treatment 2 interventions
Trial outcomes
Primary outcomes
1
Time-perception bias measured by the two-alternative forced-choice duration-comparison point of subjective equality
Participants complete a two-alternative forced-choice duration-comparison task. On each trial, they judge whether a comparison interval is shorter or longer than a standard interval. A psychometric function is fitted to each participant's responses to estimate the point of subjective equality, defined as the comparison duration judged longer than the standard on 50% of trials. Time-perception bias is calculated as signed percentage error: ((point of subjective equality - standard duration) / standard duration) × 100. Positive values indicate a point of subjective equality above the standard duration; negative values indicate a point of subjective equality below the standard duration. The primary comparison is the chronotype-by-session-time interaction, testing whether time-perception bias differs between circadian match and mismatch sessions.
Time frame
Each of two laboratory sessions, morning about 08:00 and evening about 22:00, completed within about 2 weeks.Secondary outcomes
1
Temporal precision measured by the two-alternative forced-choice duration-discrimination Weber fraction
Participants complete a two-alternative forced-choice duration-discrimination task using an adaptive staircase procedure. On each trial, they judge whether a comparison interval is shorter or longer than a standard interval. A psychometric function is fitted to estimate the just-noticeable difference, defined as the smallest duration difference required for reliable discrimination. Temporal precision is calculated as the Weber fraction: just-noticeable difference divided by the standard duration. Lower Weber-fraction values indicate better temporal precision, whereas higher values indicate poorer temporal precision.
Time frame
Each of two laboratory sessions, morning about 08:00 and evening about 22:00, completed within about 2 weeks.2
Subjective passage of time measured by a passage-of-time rating scale
Participants rate their subjective passage of time during the laboratory session using a passage-of-time rating scale. The scale ranges from 1 to 7, where 1 indicates that time passed very slowly and 7 indicates that time passed very quickly. Higher scores indicate a faster subjective passage of time, whereas lower scores indicate a slower subjective passage of time.
Time frame
Each of two laboratory sessions, morning about 08:00 and evening about 22:00, completed within about 2 weeks.3
Subjective sleepiness measured by the Karolinska Sleepiness Scale
Subjective sleepiness is assessed using the Karolinska Sleepiness Scale, a 9-point self-report scale ranging from 1 to 9. A score of 1 indicates very alert, and a score of 9 indicates very sleepy or fighting sleep. Higher scores indicate greater subjective sleepiness. The scale is administered before and after the laboratory task battery in each session; the outcome will be analysed as session-level subjective sleepiness, with pre- and post-battery ratings used to characterise changes across the session.
Time frame
Each of two laboratory sessions, morning about 08:00 and evening about 22:00, completed within about 2 weeks.4
Mood measured by the Multidimensional Mood Questionnaire
Mood is assessed using the Multidimensional Mood Questionnaire. The questionnaire provides three bipolar mood dimensions: good-bad mood, awake-tired mood, and calm-nervous mood. Each dimension is scored from 4 to 20. Higher scores indicate a more positive mood state: better mood on the good-bad dimension, greater wakefulness on the awake-tired dimension, and greater calmness on the calm-nervous dimension.
Time frame
Each of two laboratory sessions, morning about 08:00 and evening about 22:00, completed within about 2 weeks.Sponsors and contacts
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Source ClinicalTrials.gov