“Many living rooms are failures for entertaining not only because they are not colorful and are poorly lit but also because room shapes or the type and arrangement of furniture seriously depress arousal levels. Some rooms feel too large and cold and can easily be made to seem smaller by colors and textures on the walls. Since a high-load surface—one that is heavily textured and contains sharp color contrasts involving arousing colors—appears closer than a low-load one, the perceived shape of a room can be altered dramatically by judicious application of this principle. For example, ceilings can be “lowered” or “raised” by using more or less arousing colors and textures, respectively. When a room feels overly confining, less arousing surfaces must be used. A trick decorators often use is to paint opposite walls darker and lighter shades of the same color, thus making a narrow room seem wider.”

—Albert Mehrabian, from Public Places and Private Spaces: The Psychology of Work, Play, and Living Environments, 1976.