Lighting Intervention with Different Colors on Emotion: A Bayesian Network Meta-Analysis

Objective: This study aims to compare the effect of lighting interventions with different colors on emotion in healthy people. Methods: Nine studies on the effects of red, orange, yellow, green, blue, purple, and white lighting upon positive and negative emotions in healthy people were retrieved, and a network meta-analysis was conducted on the included studies via ADDIS software. The continuous variable SMD and its 95% confidence interval (CI) were used as effect sizes, and the results were analyzed using a fixed-effects model. Results: Nine experimental studies of light interventions for emotion were included, each of which included two or more light groups, with a total sample size of 848, including 848 cases of red light, 492 of orange light, 572 cases of yellow light, 492 of green light, 848 cases of blue light, 492 of violet light, and 224 of white light. From the results of a pair-wise meta-analysis, white light was significantly better than blue light (SMD=3.74, 95% CI, 2.93 to 4.54) and red light (SMD=0.82, 95% CI, 0.32 to 1.32) in enhancing positive emotions. From the network meta-analysis results, white light was more effective than yellow light in stimulating positive emotions in individuals (SMD=1.44, 95% CI, 0.01 to 2.87), without significant differences between the other groups. Conclusions: White light is more likely to stimulate positive emotions in individuals than is a typical monochromatic light such as red, yellow, or blue. Limitations: Due to the variability of emotion representation parameters in the included studies, the descaling process introduced errors in the processing of the results, and more standard and uniform quantitative studies on emotion are needed to validate the model subsequently.