Colour PerceptionNCT07671144
Visual Perception, Binocular Rivalry, and Fatigue-Related Individual Differences in Colour and Illumination Judgement
An observational study of Colour Perception and Color Perception, run by The Hong Kong Polytechnic University at 2 sites in Hong Kong.
Trial summary
This observational study aims to characterise individual differences in colour perception and binocular rivalry. Participants will complete computer-based visual perception tasks, including a colour perception task and a binocular rivalry task. Read more about this study
- Who is it for?
- Ages 18 to 25 yearsHealthy volunteers can take part
- Conditions the study is for
- Colour Perception, Color Perception, Binocular Rivalry
- What is being tested?
- Computer-Based Visual Perception Tasks
- How many people
- 128 participants
- Where
- 2 sitesHong Kong
- Study dates
- 1 Jul 2026to 30 Dec 2026
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 25 years
- All sexes
- Healthy volunteers accepted
- Adult
Study population: Healthy adult volunteers will be recruited from the university community and/or the surrounding community. Participants will complete computer-based colour perception and binocular rivalry tasks, together with self-report measures of chronotype, sleep, fatigue, and demographic characteristics.
Who may be able to join
- Adults aged 18 years or older.
- Normal or corrected-to-normal visual acuity.
- Normal or corrected-to-normal binocular vision.
- Normal colour vision, or no self-reported colour vision deficiency.
- Able to understand the study instructions and provide informed consent.
- Able to complete computer-based visual perception tasks and self-report questionnaires.
Who cannot join
- Self-reported colour vision deficiency.
- Uncorrected visual impairment or eye conditions that may interfere with visual perception tasks.
- Strabismus, amblyopia, or other binocular vision problems that may interfere with binocular rivalry testing.
- History of neurological disorders, photosensitive epilepsy, or severe sensitivity to flickering visual stimuli.
- Current condition or medication that, in the investigator's judgment, may substantially affect visual perception, attention, or task performance.
- Inability to complete the task procedures or provide valid responses.
Trial locations and contacts
2 sites in 1 country. Contact the study team or a site near you to ask about taking part.
Hong Kong2 sites, 2 recruiting
- Not yet recruiting
The Hong Kong Polytechnic University, Department of Applied Social Sciences
Hung Hom, Kowloon
Cehao Yu, PhD, +852 3400 3012, cehao.yu@polyu.edu.hk
Junkai Che, Master, +852 9783 8643, junkai.che@connect.polyu.hk
- Recruiting
Child Development Centre
Kowloon, Hung Hom
Cehao Yu, PhD, +852 3400 3012, cehao.yu@polyu.edu.hk
Cehao Yu, PhD
About this study
Official title: Characterising Individual Differences in Colour Perception and Binocular Rivalry and Their Associations With Chronotype, Sex, and Sleep
This observational study aims to characterise individual differences in colour perception and binocular rivalry. Participants will complete computer-based visual perception tasks, including a colour perception task and a binocular rivalry task. The study will first examine whether individuals show measurable differences in these perceptual responses. It will then explore whether these differences are associated with chronotype, sex, sleep-related measures, and subjective fatigue. The findings may help clarify how stable individual characteristics and daily physiological states relate to visual perception.
Read the detailed description
Colour perception and binocular rivalry both show variability across individuals. However, the extent to which these individual differences are stable and whether they are associated with personal or physiological factors remains unclear. This study will use behavioural visual perception tasks to measure individual differences in colour perception and binocular rivalry. Participants will complete a colour perception task and a binocular rivalry task, along with questionnaire measures related to chronotype, sleep, fatigue, and demographic characteristics including sex.
The primary aim is to determine whether measurable individual differences are present in colour perception and binocular rivalry performance. The secondary aim is to examine whether these differences are associated with chronotype, sex, sleep-related variables, and subjective fatigue. The study is observational and does not involve a clinical intervention, drug, biologic product, or medical device.
- Conditions
- Colour Perception, Color Perception, Binocular Rivalry
- Being tested
- Computer-Based Visual Perception Tasks
- Keywords
- Colour perception, Color perception, Binocular rivalry, Individual differences, Chronotype, Sleep, Subjective fatigue, Sex differences, Visual perception
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Computer-Based Visual Perception TasksOther
Participants will complete computer-based visual perception tasks, including a colour perception task and a binocular rivalry task. These tasks are used to measure individual differences in perceptual responses and are not intended as a clinical intervention.
| Study group | Role | What they receive |
|---|---|---|
| Healthy Adult Participants | Healthy adult volunteers aged 18 to 25 years with normal or corrected-to-normal visual acuity and normal colour vision, recruited from the university and surrounding community. In a single laboratory session, participants complete computer-based colour perception and binocular rivalry tasks and self-report questionnaires on chronotype, sleep, fatigue, and demographic characteristics. Receives: Other: Computer-Based Visual Perception Tasks |
What is being measured
The primary outcome is the main question the study is designed to answer.
Mean colour-adjustment values on the colour perception task
Colour perception will be measured using a computer-based colour adjustment task. Participants will adjust the appearance of a target object or stimulus, and outcome variables will include adjustment values in colour space, such as chromaticity, hue, saturation, or luminance-related measures, depending on the final task implementation. These measures will be used to characterise individual differences in colour perception.
Measured: Day 1 (single laboratory session)
Mean perceptual dominance duration during binocular rivalry
Binocular rivalry is measured with a computer-based dichoptic task in which a different image is presented to each eye. Perceptual dominance duration is the mean length of time, in seconds, that one stimulus remains exclusively visible before perception switches to the other. Longer mean durations indicate more stable, slower-switching rivalry.
Measured: Day 1 (single laboratory session)
Mean alternation rate during binocular rivalry
Binocular rivalry is measured with the same computer-based dichoptic task. Alternation rate is the mean number of perceptual switches between the two stimuli per minute of viewing. Higher alternation rates indicate faster perceptual switching between the two eyes' images.
Measured: Day 1 (single laboratory session)
Secondary outcomes (3)
Morningness-Eveningness Questionnaire (MEQ) score
Chronotype assessed using the Morningness-Eveningness Questionnaire (MEQ). Total scores range from 16 to 86; higher scores indicate greater morningness (a stronger morning-type preference) and lower scores indicate greater eveningness.
Measured: Day 1 (single laboratory session)
Pittsburgh Sleep Quality Index (PSQI) global score
Sleep quality assessed using the Pittsburgh Sleep Quality Index (PSQI). The global score is the sum of seven component scores and ranges from 0 to 21; higher scores indicate worse sleep quality (a global score above 5 indicates poor sleep quality).
Measured: Administered once, within 7 days before or at the single laboratory session (Day 1); the PSQI assesses sleep over the preceding 1 month.
Karolinska Sleepiness Scale (KSS) score
Subjective sleepiness/fatigue assessed using the Karolinska Sleepiness Scale (KSS), a single-item 9-point scale. Scores range from 1 to 9; higher scores indicate greater sleepiness. The pre-task to post-task change in KSS score may also be reported.
Measured: Day 1: assessed immediately before and immediately after the visual perception tasks, which are completed within a single session lasting up to approximately 1 hour.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted26 Jun 2026
- Study start1 Jul 2026
- Primary completion30 Dec 2026 (estimated)
- Study completion30 Dec 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (7)Papers the sponsor has linked to this study.
- Other trials for Colour PerceptionStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Cross-sectional
- Enrolment
- 128 participants (estimated)
Sponsor and investigators
- Lead sponsor
- The Hong Kong Polytechnic University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Dr YU Cehao, The Hong Kong Polytechnic University
- Investigators
- Cehao Yu, PhD, Principal investigator, The Hong Kong Polytechnic University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07671144
- Sponsor's protocol ID
- HSEARS20260621001
- Other IDs
- HSEARS20260621001
- Status last verified
- Jun 2026
- First submitted
- 22 Jun 2026
- Last updated
- 15 Sep 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Publications
Yang E, Blake R, McDonald JE 2nd. A new interocular suppression technique for measuring sensory eye dominance. Invest Ophthalmol Vis Sci. 2010 Jan;51(1):588-93. doi: 10.1167/iovs.08-3076. Epub 2009 Jul 23.
PubMed 19628736Webster MA, Miyahara E, Malkoc G, Raker VE. Variations in normal color vision. II. Unique hues. J Opt Soc Am A Opt Image Sci Vis. 2000 Sep;17(9):1545-55. doi: 10.1364/josaa.17.001545.
PubMed 10975364Foster DH. Color constancy. Vision Res. 2011 Apr 13;51(7):674-700. doi: 10.1016/j.visres.2010.09.006. Epub 2010 Sep 16.
PubMed 20849875Wallisch P. Illumination assumptions account for individual differences in the perceptual interpretation of a profoundly ambiguous stimulus in the color domain: "The dress". J Vis. 2017 Apr 1;17(4):5. doi: 10.1167/17.4.5.
PubMed 28388701Gegenfurtner KR, Bloj M, Toscani M. The many colours of 'the dress'. Curr Biol. 2015 Jun 29;25(13):R543-4. doi: 10.1016/j.cub.2015.04.043. Epub 2015 May 14.
PubMed 25981790Lafer-Sousa R, Hermann KL, Conway BR. Striking individual differences in color perception uncovered by 'the dress' photograph. Curr Biol. 2015 Jun 29;25(13):R545-6. doi: 10.1016/j.cub.2015.04.053. Epub 2015 May 14.
PubMed 25981795Toscani M, Gegenfurtner KR, Doerschner K. Differences in illumination estimation in #thedress. J Vis. 2017 Jan 1;17(1):22. doi: 10.1167/17.1.22.
PubMed 28141875
Study at a glance
From the registry record, last updated by the sponsor on 15 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Characterising Individual Differences in Colour Perception and Binocular Rivalry and Their Associations With Chronotype, Sex, and Sleep
- ClinicalTrials.gov ID
- NCT07671144
- Acronym / sponsor ID
- HSEARS20260621001
- Conditions
- Colour Perception, Color Perception, Binocular Rivalry
- Keywords
- Colour perception, Color perception, Binocular rivalry, Individual differences, Chronotype, Sleep, Subjective fatigue, Sex differences
- Study type
- Observational
- Recruitment status
- Recruiting
- Enrolment
- 128 participants (estimated)
- Lead sponsor
- The Hong Kong Polytechnic UniversityUniversity, hospital or other
- Study start
- 1 Jul 2026 (actual)
- Primary completion
- 30 Dec 2026 (estimated)
- Study completion
- 30 Dec 2026 (estimated)
- First posted
- 26 Jun 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This observational study aims to characterise individual differences in colour perception and binocular rivalry. Participants will complete computer-based visual perception tasks, including a colour perception task and a binocular rivalry task. The study will first examine whether individuals show measurable differences in these perceptual responses. It will then explore whether these differences are associated with chronotype, sex, sleep-related measures, and subjective fatigue. The findings may help clarify how stable individual characteristics and daily physiological states relate to visual perception.
Detailed description
Colour perception and binocular rivalry both show variability across individuals. However, the extent to which these individual differences are stable and whether they are associated with personal or physiological factors remains unclear. This study will use behavioural visual perception tasks to measure individual differences in colour perception and binocular rivalry. Participants will complete a colour perception task and a binocular rivalry task, along with questionnaire measures related to chronotype, sleep, fatigue, and demographic characteristics including sex.
The primary aim is to determine whether measurable individual differences are present in colour perception and binocular rivalry performance. The secondary aim is to examine whether these differences are associated with chronotype, sex, sleep-related variables, and subjective fatigue. The study is observational and does not involve a clinical intervention, drug, biologic product, or medical device.
Study design
- Observational model
- Cohort
- Time perspective
- Cross-sectional
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Healthy Adult Participants | – | Other: Computer-Based Visual Perception TasksHealthy adult volunteers aged 18 to 25 years with normal or corrected-to-normal visual acuity and normal colour vision, recruited from the university and surrounding community. In a single laboratory session, participants complete computer-based colour perception and binocular rivalry tasks and self-report questionnaires on chronotype, sleep, fatigue, and demographic characteristics. |
Who may qualify
- Ages
- 18 to 25 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
- Study population
- Healthy adult volunteers will be recruited from the university community and/or the surrounding community. Participants will complete computer-based colour perception and binocular rivalry tasks, together with self-report measures of chronotype, sleep, fatigue, and demographic characteristics.
Key inclusion criteria (6 listed)
- Adults aged 18 years or older.
- Normal or corrected-to-normal visual acuity.
- Normal or corrected-to-normal binocular vision.
- Normal colour vision, or no self-reported colour vision deficiency.
- Able to understand the study instructions and provide informed consent.
Key exclusion criteria (6 listed)
- Self-reported colour vision deficiency.
- Uncorrected visual impairment or eye conditions that may interfere with visual perception tasks.
- Strabismus, amblyopia, or other binocular vision problems that may interfere with binocular rivalry testing.
- History of neurological disorders, photosensitive epilepsy, or severe sensitivity to flickering visual stimuli.
- Current condition or medication that, in the investigator's judgment, may substantially affect visual perception, attention, or task performance.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Computer-Based Visual Perception TasksParticipants will complete computer-based visual perception tasks, including a colour perception task and a binocular rivalry task. These tasks are used to measure individual differences in perceptual responses and are not intended as a clinical intervention. | Other | Healthy Adult Participants |
Primary outcome
Mean colour-adjustment values on the colour perception task
Time frame: Day 1 (single laboratory session)
Colour perception will be measured using a computer-based colour adjustment task. Participants will adjust the appearance of a target object or stimulus, and outcome variables will include adjustment values in colour space, such as chromaticity, hue, saturation, or luminance-related measures, depending on the final task implementation. These measures will be used to characterise individual differences in colour perception.
Mean perceptual dominance duration during binocular rivalry
Time frame: Day 1 (single laboratory session)
Binocular rivalry is measured with a computer-based dichoptic task in which a different image is presented to each eye. Perceptual dominance duration is the mean length of time, in seconds, that one stimulus remains exclusively visible before perception switches to the other. Longer mean durations indicate more stable, slower-switching rivalry.
Mean alternation rate during binocular rivalry
Time frame: Day 1 (single laboratory session)
Binocular rivalry is measured with the same computer-based dichoptic task. Alternation rate is the mean number of perceptual switches between the two stimuli per minute of viewing. Higher alternation rates indicate faster perceptual switching between the two eyes' images.
3 secondary outcomes
Morningness-Eveningness Questionnaire (MEQ) score
Time frame: Day 1 (single laboratory session)
Pittsburgh Sleep Quality Index (PSQI) global score
Time frame: Administered once, within 7 days before or at the single laboratory session (Day 1); the PSQI assesses sleep over the preceding 1 month.
Karolinska Sleepiness Scale (KSS) score
Time frame: Day 1: assessed immediately before and immediately after the visual perception tasks, which are completed within a single session lasting up to approximately 1 hour.
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 15 Sep 2026.
- Background: PubMed 19628736Yang E, Blake R, McDonald JE 2nd. A new interocular suppression technique for measuring sensory eye dominance. Invest Ophthalmol Vis Sci. 2010 Jan;51(1):588-93. doi: 10.1167/iovs.08-3076. Epub 2009 Jul 23.
- Background: PubMed 10975364Webster MA, Miyahara E, Malkoc G, Raker VE. Variations in normal color vision. II. Unique hues. J Opt Soc Am A Opt Image Sci Vis. 2000 Sep;17(9):1545-55. doi: 10.1364/josaa.17.001545.
- Background: PubMed 20849875Foster DH. Color constancy. Vision Res. 2011 Apr 13;51(7):674-700. doi: 10.1016/j.visres.2010.09.006. Epub 2010 Sep 16.
- Background: PubMed 28388701Wallisch P. Illumination assumptions account for individual differences in the perceptual interpretation of a profoundly ambiguous stimulus in the color domain: "The dress". J Vis. 2017 Apr 1;17(4):5. doi: 10.1167/17.4.5.
- Background: PubMed 25981790Gegenfurtner KR, Bloj M, Toscani M. The many colours of 'the dress'. Curr Biol. 2015 Jun 29;25(13):R543-4. doi: 10.1016/j.cub.2015.04.043. Epub 2015 May 14.
- Background: PubMed 25981795Lafer-Sousa R, Hermann KL, Conway BR. Striking individual differences in color perception uncovered by 'the dress' photograph. Curr Biol. 2015 Jun 29;25(13):R545-6. doi: 10.1016/j.cub.2015.04.053. Epub 2015 May 14.
- Background: PubMed 28141875Toscani M, Gegenfurtner KR, Doerschner K. Differences in illumination estimation in #thedress. J Vis. 2017 Jan 1;17(1):22. doi: 10.1167/17.1.22.
- Individual participant dataSharing planned: Undecided
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Cehao Yu, PhD principal investigator
The Hong Kong Polytechnic University
2 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Colour Perception and Color Perception, run by The Hong Kong Polytechnic University at 2 sites in Hong Kong.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 6 inclusion and 6 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 15 Sep 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 2 sites in Hong Kong. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Cehao Yu, PhD (+852 3400 3012, cehao.yu@polyu.edu.hk), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Mean colour-adjustment values on the colour perception task (time frame: Day 1 (single laboratory session)). The study lists 3 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07671144, which also lists 7 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 15 Sep 2026.