The effects of light illuminance and correlated color temperature on mood and creativity

The lighting environment is one of the indoor environmental factors that may influence creativity. The combined effects of illumination (300 lx vs. 2000 lx) and color temperature (3000 K vs. 6000 K) on mood and creativity were investigated in 24 participants. During exposure, participants completed questionnaires to assess their mood and lighting perceptions, performed creative and analytical tasks, and collected saliva samples for analysis of melatonin concentration. An interactive effect of illuminance and color temperature on the mood was observed. The participants performed better on the performance of Flexibility, Fluency and Originality in the verbal creative task when they expressed higher positive mood (at 2000 lx, 6000 K and 300 lx, 3000 K) and performed better on the performance of Resistance to closure in the figural creative task when they reported the lowest positive mood (at 2000 lx, 3000 K). Analytical thinking, including calculation and echoic memory skills, was facilitated at the lighting setting (300 lx, 6000 K) that induced the least affective intensity. No significant difference in melatonin concentration was observed. This evidence implies that the affective state of the occupants was influenced by light and that their creative performance was altered accordingly. These findings will help to elaborate a design guideline on the lighting environment according to the specific needs of different tasks.