Effects of colour of light on nonvisual psychological processes

This study investigated the influence of colour of light ('warm', 'cool' and artificial 'daylight' white lighting) on subjects' self-reported mood, cognitive performance and room light estimation. Although no direct effect on positive and negative mood was indicated, a main effect of gender on several room light estimation dimensions showed that females perceived the room light, across all light settings, as more expressive than did males. Cognitive task data revealed findings not earlier indicated by the behavioural lighting research. Main effects of colour of light on short-term memory and problem solving showed that subjects performed better in the 'warm' than in the 'cool' and artificial 'daylight' white lighting. Interaction effects between colour of light and gender on long-term memory showed that males performed best in the 'warm' and 'cool' white lighting, and that women performed better than men in the artificial 'daylight' white lighting. All these results are generally in agreement with the proposition that light influences nonvisual psychological processes. (C) 2001 Academic Press.