Physiological and psychological effects of illumination and colour in the interior environment

Abstract

There exists a growing body of research findings uncovering the non-visual effects of artificial lighting. In a recently completed field study we compared the effects of two types of fluorescent lighting, the daylight tube versus the common white tube. Persons working in two otherwise identical drawing offices were studied for one year. The results support the conclusion that light from the daylight tube blocks the production of the sleep hormone melatonin to a greater extent than light from the white fluorescent tube. Sitting indoors in window-less localities also changes the production of stress hormones like cortisol. That not only light but the total visual environment is important was demonstrated in a study of high versus low visual complexity. The results showed that colours and patterns stimulate the brain's electrical activity. In contrast, the pulse rate was lowered in the complex room, which might be interpreted as a compensatory response to visual overstimulation. In conclusion, the results indicate that the total visual environment has a much deeper influence upon people than has been supposed hitherto. © 1986, The Illuminating Engineering Institute of Japan. All rights reserved.