Proceedings of 2nd International Symposium for Color Science and Art 2020

Comparative Analysis on the Effect of Illumination Color inClinical Environment of Preventive CareTsuyoshi Moriyama*, Takumi Shimada*, Takahiko Sakai**,Shun Nakamura***, Katsuyoshi Kasahara**** and Ichiro Urata*****Tokyo Polytechnic Univ., 1583 Iiyama, Atsugi, Kanagawa 243-0297, Japan**Tokyo Polytechnic Univ., 2-9-5 Honcho, Nakano, Tokyo 164-8678, Japan***Corlab Inc., 2-24-16 Nakacho, Koganei, Tokyo 184-8588, Japan**** Urata Clinic, 1-26 Hongo, Uozu, Toyama 937-0805, Japan
could empower him or her by sending cheers. So is thecase in the working environment where intellectual
performance is required except for physical one.
Recent progress in lighting technology using LED has
enabled to use full color lights in daily life. However, noscientific evidences support what color lighting stimuli
could be another cheering environmental factor because
conventional room lights were only white with a variety ofcolor temperatures and industrial standards for lighting
have all based on them [1]. Not only houses but also
workplaces these days pay much attention to theenvironmental conditions so that to maximize theperformance of workers in them by improving the quality of
their lives, which is critical under the circumstances ofshortage of workers in Japan.
In this paper, we report an experimental result where
the subjects executed cognitive tasks under a specific setof colored illuminations to see how they affect the task
score and the biological responses of humans.

ABSTRACT
Conventional lights used in house were only white and theindustrial standard that has recommended the optimal
usage of lights have based on the color temperature.
Illumination used in daily life these days has extended toprovide the capability of using full color lights thanks torecent progress of LED lighting technology, but thestandard mentioned above has not considered the effectof color lights on humans yet. Here we investigated theeffect of colored lighting conditions on human cognitive
performance by conducting an experiment where thesubjects from multiple elderly generations executedcognitive tasks under several specific illumination
conditions with color to see how the task score and their
biological responses would vary among the conditions.
1. INTRODUCTION
Humans have nature for adopting to their environment
and keeping social balance with others by using all theirsenses, i.e., vision, auditory, olfactory, gustatory, andtactile. From a different point of view, the environment
including other people that surround a person may change
the way of affecting him or her so that he or she could
enhance the ability for doing tasks. Cheering in a sport
event is one of the examples where the audience plays therole of surrounding environment of a sport player that

2. EXPERIMENTS
2.1 Cognitive tasks
We exploited CogEvo that is widely used in research
institutes as, so to speak, de facto standard [2]. It divides
a measurement task for cognitive performance into fivecategories, 1) spatial awareness, 2) orientation, 3)
memory, 4) attention, and 5) planning. Every task is a kindof game and takes fifteen to twenty minutes in total tofinish.
2.2 Subjects
Three elderly generations across fifties to seventies
with twelve subjects(six for both males and females) were
instructed to do the task explained in Section 2.1. Theyare healthy and cognitively clear. They understand theexperiment and the task and are able to do the task
without any accidental mistakes.
2.3 Experiment room and illumination conditions
Fig.1 shows the experiment room where the subject sits
next to the instructor who teaches the subject how to do
every task. A camera system that has thermos-camera
and optical camera stuck together locates in front of thesubject, and another video camera diagonally behind theFig. 1 Experiment room11

Proceedings of 2nd International Symposium for Color Science and Art 2020(a) red(b) green(c) blueFig. 2 Color conditions for calculation task.

subject that takes the scene of doing tasks and all. The
subject puts on heart beat sensor (myBeat [3]) at thebeginning.
Two LED lights locates under the wall facing the subject
that illuminate the whole wall and the ceiling over the wall,
which is the entire view of the subject in other words. The
illumination of every color was set to the maximum
illumination of red. Each subject did the task under asingle illumination condition assigned.

seventies compared with fifties and sixties).
Blinking rate counted the highest number in seventies.
In addition, it counted higher in red light compared withgreen and blue when significantly different (spatialawareness for fifties and sixties, and memory for fifties).
Red light might have forced difficulty in memorization andgetting aware of space.
4. CONCLUSION AND FUTURE WORK
We conducted an experiment that varied illumination
colors when subjects did cognition tasks. The task scores
correlated with the age, the biological metrics of heartbeat
rate and eye-blinking rate, and the illumination colors. The
result demonstrated that planning task for sixties
enhances under blue light. In addition, red light seemed togive load to cognitive task that led to higher rate of eye
blinking.
Future work include extending the experiment tocognitive performance in younger generation and also
human communication that could be affected by coloredillumination.

2.4 Measurements
The thermo-camera captures the temperature of theskin around root nose that correlates with theconcentration (the optical camera detects face region andfacial components from the image). The heartbeat sensorcaptures heartbeat wave whose specific frequency
components correlate with nerve activities [4]. Also, theoptical camera gives the number and the timing ofeye-blinking that is known to be an indicator of memory
process in brain activity [5][6].
Those measurements were later analyzed with respect
to the age, the task score, and the illumination conditions
where three subjects for each generation (fifties, sixties,and seventies) conducted the task under the same
illumination condition.

Acknowledgement
This work was supported by “FY2016 MEXT Private
University Research Branding Project”.

2.5 Results
As the subjects got older, the score for every task got
worse just as anticipated. Illumination condition did notaffect fifties and seventies in every cognitive task. Only insixties, a significant difference was found in the planningtask (see Fig.3). The score under blue lighting condition
topped those in green and white with 1% and 5%
significance level respectively. Blue light would enhance
the ability of planning (planning ability decreased in**

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REFERENCES[1] JIS Illumination Standard,
http://kikakurui.com/z9/Z9110-2011-01.html, (2010).
[2] CogEvo, https://cog-evo.jp/, (as of 2020).
[3] myBeat, https://www.uniontool-mybeat.com/, UNIONTOOL CO., (as of 2020).
[4] Takahashi K., and Inoue H., “A Quantitative Analysis
on Stress and Fatigue for VDT Workers Measured byHeart Rate Variability (HRV), “ Departmental Bulletin
Paper of Akita University, 30’1-7, (2009).
[5] Yamamoto, H., Shimizu, Y., “Change of pupil sizeand blinking time in memorizing numerals, “ Journalof the Institute of Television Engineers of Japan,
45(3):370-376, (1991).
[6] Nakano, T., “A New Role of Default Mode Network
Revealed by Eyeblink, “ Physiological psychology
and psychophysiology, 31(1):19-26, (2013).

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redgreenblue(d) white

whiteFig. 3 Comparison of task scores between illumination
conditions (Planning for sixties).

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