Visual Perception, Binocular Rivalry, and Fatigue-Related Individual Differences in Colour and Illumination Judgement

NCT07671144 | Not Yet Recruiting

• 1 other identifier: HSEARS20260621001
• Study Type: observational
• Target: 128
• Locations: 1 country
• Sites: 1

Brief 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. 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.

Conditions

Colour Perception; Color Perception; Binocular Rivalry

Keywords

Colour perception; Color perception; Binocular rivalry; Individual differences; Chronotype; Sleep; Subjective fatigue; Sex differences; Visual perception

Outcome Measures

Primary Outcomes (3)

• 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.

  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.

  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.

  Day 1 (single laboratory session)

Secondary Outcomes (3)

• Morningness-Eveningness Questionnaire (MEQ) score

  Day 1 (single laboratory session)

• Pittsburgh Sleep Quality Index (PSQI) global score

  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

  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.

Study Arms (1)

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.

Other: Computer-Based Visual Perception Tasks

Interventions

Computer-Based Visual Perception Tasks OTHER

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.

Healthy Adult Participants

Eligibility Criteria

• Age: 18 Years - 25 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)
• Sampling Method: Non-Probability Sample

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.

You may qualify if:

• 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.

You may not qualify if:

• 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.

Sponsors & Collaborators

• The Hong Kong Polytechnic University: lead

Study Sites (1)

The Hong Kong Polytechnic University, Department of Applied Social Sciences

Hung Hom, Kowloon, Hong Kong

Location

Related Publications (7)

• 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.

  PMID: 19628736 BACKGROUND

• Webster 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.

  PMID: 10975364 BACKGROUND

• Foster DH. Color constancy. Vision Res. 2011 Apr 13;51(7):674-700. doi: 10.1016/j.visres.2010.09.006. Epub 2010 Sep 16.

  PMID: 20849875 BACKGROUND

• Wallisch 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.

  PMID: 28388701 BACKGROUND

• Gegenfurtner 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.

  PMID: 25981790 BACKGROUND

• Lafer-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.

  PMID: 25981795 BACKGROUND

• Toscani 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.

  PMID: 28141875 BACKGROUND

Study Officials

• Cehao Yu, PhD

  The Hong Kong Polytechnic University

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Cehao Yu, PhD

CONTACT

+852 3400 3012; cehao.yu@polyu.edu.hk

Junkai Che, Master

CONTACT

+852 9783 8643; junkai.che@connect.polyu.hk

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: CROSS SECTIONAL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Research assistant professor

Study Record Dates

• First Submitted: June 22, 2026
• First Posted: June 26, 2026
• Study Start: July 1, 2026
• Primary Completion (Estimated): December 1, 2026
• Study Completion (Estimated): December 1, 2026
• Last Updated: July 6, 2026

Record last verified: 2026-06

Locations

HK (1)