The Effects Of Correlated Color Temperature And Illumination On Mood And Creative Performance

Light is an essential environmental element that has a tremendous impact on peoples' physiology and psychology.Workers who spend most of their time enclosed in their office space,are directly exposed to these effects.In this study the effects of lighting illuminance and color temperature on occupant's mood and cognitive performance were investigated.Two illuminance levels,i.e.,300 lx and 2000 lx and two color temperatures,i.e.,3000 K and 6000 K were set,creating four experimental conditions.twenty-four participants from a design related background were recruited to participate in the experimental study.In the experiment they performed tasks investigating creative and analytical thinking including divergent thinking,problem solving and cognitive abilities,(calculation and memory).During exposure they filled out some questionnaires to assess their light perception,subjective work performance evaluation,and mood using PANAS affect scale.Biomarker of melatonin concentration in the saliva was tested as an objective mean to observe the physiological effects of light on occupants.The results of the mood questionnaires indicate that positive affect increased under 2000lx6000 K and the 300lx3000 K light.For the negative affect no significant difference was detected.As expected,a significant difference in gender effect was observed.Interestingly,the females showed a higher sensitivity to the lighting variations but less expression of affect.The males on the other hand,showed higher affective intensity with higher sensitivity to light.As to the task performance,creative thinking was facilitated by the 2000lx6000 K and the 300lx3000 K light under positive affect while analytical thinking improved with low affective intensity generated by the 300lx6000 K.These findings could serve as a predictor of the cognitive performance of employees and would help optimize the working environment according to the specific needs of these workers.