Effects of Illuminance and Correlated Color Temperature on Daytime Cognitive Performance, Subjective Mood, and Alertness in Healthy Adults

Zhu, Yingying; Yang, Ming; Yao, Ying; Xiong, Xiao Yi; Li, Xiaoran; Zhou, Guofu; Ma, Ning

doi:10.1177/0013916517738077

“…The studies focused on separating the effects of the illuminance of the walls and that of the task surface, as they are often confounded in office lighting studies. 2,18,20 In the first experiment, reported elsewhere, 21 wall illuminance was varied while keeping illuminance at the desk and the eye constant. It demonstrated a sustaining effect on subjective alertness when using a higher wall luminance.…”

Section: Introductionmentioning

confidence: 99%

Teasing apart office illumination: Isolating the effects of task illuminance on office workers

Vries

¹

,

Souman

²

,

Kort

³

2020

Lighting Research & Technology

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Task illuminance is one of the most used parameters in office lighting design and is often used as a ‘single number criterion’ to verify that a lighting design meets the requirements. Although other parameters, such as wall luminance, are often highly correlated with task illuminance, not taking these explicitly into account means critical user criteria such as comfort and satisfaction are left to chance. In this study, we investigated the effect of varying desk illuminance(150 lux to 1500 lux) while keeping wall luminance constant, isolating the effects of illuminance on the desk and eye on office users’ overall perception of the space, their mental state and their performance (visual and cognitive). While both visual acuity (paper-based) and perceived brightness increased significantly with higher desk illuminance, the room’s attractiveness did not. Even though illuminance at the eye increased considerably with desk illuminance (from 118 lux to 796 lux), only minor effects were found on subjective alertness and cognitive performance. This suggests that focusing on horizontal task illuminance as a design parameter is appropriate in view of visual acuity but has little to no effect on the space’s attractiveness, nor on cognitive performance or mental state of the office worker.

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“…Also, the majority of researches about the effects of light were carried out together with cognitive tasks, e.g. go/no-go, N -back working memory, Psychomotor Vigilance Task, Flanker task, long-term memory, and emotional judgment task 13 , 16 , 17 , 22 , 25 . The tasks performed during light exposure and associated (potential) fatigue might also confound the effects of light on subjective affect and comfort 26 .…”

Section: Introductionmentioning

confidence: 99%

The effects of short-term light exposure on subjective affect and comfort are dependent on the lighting time of day

Chen

¹

,

Feng

²

,

Fan

³

et al. 2021

Sci Rep

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Light, one of the key environmental components for both life and work, played significant role in subjective feelings (e.g. affect and comfort), but the exact effects and mechanisms were still to be determined. The present study screened thirty healthy adults (13 females, 22.45 ± 3.26 years) and examined subjective affect and comfort under short-term white lights with different combination of correlated color temperature (CCT) and illuminance at different times of day (e.g. morning, afternoon, and evening). Our results showed a significant interaction between illuminance level and time-of-day on subjective comfort. Participants felt more comfortable under 50 lx and 100 lx instead of 500 lx in the evening, and more comfortable under 500 lx in the morning and afternoon. In addition, a positive correlation between illuminance and comfort in the morning and a negative correlation between them in the evening were found. No significant effect of CCT on any subjective feeling was revealed. Our results necessitate the consideration of time-of-day in understanding lighting effects and application of healthy lighting in daily life.

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“…Also, the majority of researches about the effects of light were carried out together with cognitive tasks, e.g. go/no-go, N-back working memory, Psychomotor Vigilance Task, Flanker task, long-term memory, and emotional judgment task 13,16,17,22,25 . The tasks performed during light exposure and associated (potential) fatigue might also confound the effects of light on subjective affect and comfort 26 .…”

Section: Introductionmentioning

confidence: 99%

Time-of-day Dependent Light Effects on Subjective Affect and Comfort

Chen

¹

,

Feng

²

,

Fan

³

et al. 2020

Preprint

0

View full text Add to dashboard Cite

Light, one of the key environmental components for both life and work, played significant role in subjective feelings (e.g. affect and comfort), but the exact effects and mechanisms were still to be determined. The present study screened thirty healthy adults (13 females, 22.45 ± 3.26 years) and examined subjective affect and comfort under short-term white lights with different combination of correlated color temperature (CCT) and illuminance at different times of day (e.g. morning, afternoon, and evening). Our results showed a significant interaction between illuminance level and time-of-day on subjective comfort. Participants felt more comfortable under 50 lx and 100 lx instead of 500 lx in the evening, and more comfortable under 500 lx in the morning and afternoon. In addition, a positive correlation between illuminance and comfort in the morning and a negative correlation between them in the evening were found. No significant effect of CCT on any subjective feeling was revealed. Our results necessitate the consideration of time-of-day in understanding lighting effects and application of healthy lighting in daily life.

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Effects of Illuminance and Correlated Color Temperature on Daytime Cognitive Performance, Subjective Mood, and Alertness in Healthy Adults

Cited by 82 publications

References 59 publications

Teasing apart office illumination: Isolating the effects of task illuminance on office workers

Teasing apart office illumination: Isolating the effects of task illuminance on office workers

The effects of short-term light exposure on subjective affect and comfort are dependent on the lighting time of day

Time-of-day Dependent Light Effects on Subjective Affect and Comfort

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