Lighting for Pedestrians’ Interpersonal Evaluations: Is the Face the Critical Cue?

Road lighting in minor roads is designed primarily for the needs of pedestrians and cyclists. Pedestrians’ considerations include their safety and their feeling of safety after-dark. One factor that contributes to a pedestrian’s feeling of safety is the ability to evaluate other people (known as interpersonal evaluations); road lighting should enhance the ability to make the visual component of this evaluation. While past lighting studies have assumed the face is the critical target, and hence investigated the effect of lighting on facial recognition, this assumption has yet to be verified. Different personal features subtend targets of different sizes, colours, and contrasts, so a better understanding of the important visual cues is essential for appropriate research.

Three experiments were conducted to investigate the visual cues used by pedestrians in interpersonal evaluations. The first two used a subjective evaluation procedure, in which images portraying pedestrians in different situations were evaluated using either category rating or both category rating and paired comparisons. The assumption was that those situations rated (or chosen) as less safe would indicate critical visual cues. Experiment 1 compared the relative importance of gender, number of people, walking direction, direction of the fall of light, and the exposure of the face and hands: the results suggested that the exposure of face and hands had a greater effect than other cues, but did not distinguish between the face and hands. Experiment 2 was therefore conducted to further investigate exposure to view of the face and hands: the results suggested that the face is a more important cue than the hands. To test the robustness of these findings, Experiment 3 investigated the same question as Experiments 1 and 2 but used an objective measure, eye-tracking. The core assumption was that the most important visual cue in a scene is that which receives the first visual fixation and the longest duration of visual fixations: the results again suggested that the face is the most important visual cue in interpersonal evaluations.

It is therefore concluded that the face is the key visual cue used in pedestrians’ interpersonal evaluations. This supports the assumption of previous research investigating the effect of changes in lighting for pedestrians.