How lighting can affect social cognition and behaviours

The psychological mechanism of lighting is complex but overlooked in the research field. Despite this, lighting is believed to influence the social dimension of people through the perceptual pathway, by sending visual messages that can be affective, cognitive, associative and motivational. Lighting can positively influence the impression of the luminous atmosphere that socially includes/invites or excludes/rejects people. It can also affect social appraisal, which can drive positive affective interpersonal behaviours. Since little is yet established about the interplay between lighting and the psycho-social response of individuals, this research would investigate how lighting distribution, correlated colour temperature (CCT) and lighting levels (bright/dim) could influence territoriality perception, social proximity and closeness between individuals. The research was conducted through several phases: (i) design of the experimental lighting fixture and environment; (ii) tests of the social lighting effects between different lighting settings; (iii) data qualitative and quantitative analysis; (iv) physical measurements of lighting (Luminance, Illuminance). The experiments were conducted in a laboratory room (dimensions: 4m x 6m) located in the Design Department of the Politecnico di Milano. The results of the experiment show that lighting can affect social spacing and territorial behaviours but this may depend also on personal, environmental and social factors. In this experiment, the warm CCT with dim lighting levels appeared to contribute to the length of conversation, while the light distribution was seen as influencing preferences regarding interpersonal distance. In addition to lighting, the setting of proxemics distances seems to be also dependent on the level of acquaintance between participants. With regard to the postural attitudes, participants demonstrated more openness in the warm dim direct/indirect lighting setting, regardless of their gender and acquaintance.