The present study primarily concerns the relationship between coloured lighting (red and blue, with white as an achromatic control) and attraction toward another individual; an individual who may have similar or dissimilar attitudes to those of the subject. The question asked was whether the colour of a room's illumination affected interpersonal evaluation of another person whom the subject had not previously met. That is, will coloured illumination affect liking of the stranger either negatively or positively, over and above the effect that knowledge of the stranger's attitudes will have on the subject's judgement? Is attraction a function of colour of environmental illumination and attitude similarity? Questions subsidiary to the above but of basic importance to the present study are; whether mood is affected positively or negatively by coloured room environment; whether concepts are more negatively or positively evaluated under different colour conditions and whether aspects of semantic meaning are differentially affected under different lighting conditions. Finally Berry's (1961) finding of different heat perception over colour environments was retested.