Effects of Outdoor Lighting on Judgements of Emotion and Gaze Direction

Road lighting in residential roads should enhance the visual component of interpersonal judgements concerning the apparent intent of other pedestrians – whether friendly, aggressive or indifferent. This paper describes an experiment which collected forced-choice judgements of emotion and gaze direction after 1000 ms exposure under 18 combinations of lamp type, luminance and interpersonal distances. Better performance was found with higher luminance and larger task size, but with diminishing returns according to a plateau-escarpment relationship. The results were used to estimate appropriate light levels for outdoor lighting. Results for judgements of emotion from facial expression suggest a minimum luminance of the face of 0.1–1.0 cd/m2 if facial expressions are to be identified accurately at 4 m, but a luminance above 1.0 cd/m2 for identification at 10 m.