Fig 1.
The four light experimental light conditions and the experimental procedure of one session.
(A) cool, bright light (CB), (B) cool, dim light (CD), (C) warm, bright light (WB), and (D) warm, dim light (WD). Participants were exposed to these four conditions in separate sessions on different days in partial counterbalanced order. Q: Questionnaire, PVT: Psychomotor Vigilance Task, and BDST: Backward Digit Span Task.
Table 1.
Participant descriptors.
Fig 2.
Spectral power distributions of the light settings.
Table 2.
α-opic EDI, illuminance and CCT on the eye of the light settings.
Fig 3.
Trajectories of visual experience parameters.
(A) sensation of light intensity, (B) sensation of color temperature, (C) visual acceptance (in %—no statistical testing), and (D) visual comfort. Error bars are standard errors (SE). Contrasts for illuminance and CCT were done for each measurement block: + indicates p < .01 for CCT, * p < .01 for illuminance.
Table 3.
Statistics for the main predictors for all outcome parameters.
Fig 4.
Individual differences in the visual comfort evaluation.
Individual values of visual comfort are calculated using the EMM + P00k + P3k * x based on the model with random slopes for (A) Illuminance and (B) CCT.
Fig 5.
Trajectories of vitality, sleepiness and performance parameters.
(A) vitality, (B) sleepiness, (C) mean reaction time for PVT, (D) effort during the PVT, (E) correct responses for BDST, and (F) effort during the BDST. Error bars are SE. Contrasts for illuminance and CCT were done for each measurement block: + indicates p < .01 for CCT, * p < .01 for illuminance.
Fig 6.
Trajectories of physiological parameters.
(A) mean SCL, (B) mean HR, and (C) mean HRV. Error bars are SE. No significant differences existed for illuminance and CCT in any of the measurement blocks.
Fig 7.
Trajectories of mood parameters.
(A) Calm, and (B) Happy. Error bars are SE. Contrasts for illuminance and CCT were done for each measurement block: + indicates p < .01 for CCT, * p < .01 for illuminance.
Fig 8.
Trajectories of thermal experience parameters.
(A) thermal sensation, (B) self-assessed shivering, (C) thermal acceptance (in %—no statistical testing), and (D) thermal comfort. Error bars are SE. No significant differences existed for illuminance and CCT in any of the measurement blocks.
Fig 9.
Trajectories of thermoregulation related parameters.
(A) average skin temperature, and (B) distal-to-proximate gradient. Error bars are SE. No significant differences existed for illuminance and CCT in any of the measurement blocks.