Chronotype Alignment and Time Perception

The Hong Kong Polytechnic University

Status: Enrolling

Conditions: Time Perception; Circadian Rhythm; Chronotype; Sleep

Treatments: Behavioral: Morning test session (about 08:00); Behavioral: Evening test session (about 22:00)

Study type: Interventional

Funder types: Other

Identifiers

NCT07677111

HSEARS20260622001

Details and patient eligibility

About

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.

Full description

Background and rationale: Time perception is shaped by attention and physiological arousal, both of which follow a circadian rhythm that differs systematically between morning-type and evening-type individuals. The "synchrony effect" holds that performance is optimal when testing occurs at a person's circadian-preferred time. Whether this match/mismatch alters the perceived speed and precision of an internal clock, and whether any such effect generalises across cultures and latitudes, is not well established.

Design: a 2 (chronotype: morning-type vs evening-type; between-subjects) x 2 (session time: morning about 08:00 vs evening about 22:00; within-subjects, counterbalanced) mixed design, replicated at three sites. "Match" = tested at the circadian-preferred time; "mismatch" = tested at the non-preferred time. Site is included as an additional factor for generalisability.

Procedure: volunteers are screened online (Morningness-Eveningness Questionnaire to classify chronotype, with intermediate types excluded; Munich ChronoType Questionnaire; Pittsburgh Sleep Quality Index; demographics; colour-vision and health checks) and keep a 7-day sleep diary. Eligible participants attend two laboratory sessions and complete an identical battery each time: time-perception tasks (interval production/estimation, duration discrimination, passage-of-time judgement), state measures (sleepiness, mood, arousal), colour tasks (unique-hue settings with and without blue-blocking glasses; an ambiguous-colour image), a perceptual conformity task, and a vigilance task.

Primary hypothesis: a chronotype-by-time-of-day interaction on time-perception bias. Analysis uses linear mixed-effects models (participant as a random effect; chronotype, session time, their interaction, and site as fixed effects), with false-discovery-rate correction across secondary outcomes. Session order is counterbalanced to separate time-of-day from practice and order effects.

Enrollment: 240 estimated patients

Sex: All

Ages: 18 to 55 years old

Volunteers: Accepts Healthy Volunteers

Inclusion criteria

• 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)
• Fluent in the testing-site language (Danish, Chinese, or English)
• Able to attend both an early-morning (about 08:00) and a late-evening (about 22:00) session

Exclusion criteria

• 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
• Use of sleep medication or psychoactive or CNS-active drugs
• Colour-vision deficiency
• Substance-use disorder

Trial design

Primary purpose: Basic Science

Allocation: Randomized

Interventional model: Crossover Assignment

Masking: None (Open label)

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240 participants in 2 patient groups

Morning-first sequence

Experimental group

Description:

Participants complete the Morning test session (about 08:00) first, then the Evening test session (about 22:00). Both sessions use the identical perception and cognition battery; session order is counterbalanced across participants.

Treatment:

Behavioral: Evening test session (about 22:00)

Behavioral: Morning test session (about 08:00)

Evening-first sequence

Experimental group

Description:

Participants complete the Evening test session (about 22:00) first, then the Morning test session (about 08:00). Both sessions use the identical perception and cognition battery; session order is counterbalanced across participants.

Treatment:

Behavioral: Evening test session (about 22:00)

Behavioral: Morning test session (about 08:00)