How do the Indoor Illumination Levels Affect Social and Cognitive Behaviors?

Abstract

: The indoor illumination levels affect emotional states, interpersonal impressions, and psychological distance between the self and others. In this study, we conducted experiment on the effect of the brightness of the room on face-to-face communication between participants as interviewee and the interviewer. Conducting a two-factor mixed analysis of variance on “illumination levels × pre- and post-evaluation,” we observed that in dim conditions, the interpersonal distance between the participants and interviewer became significantly closer. The psychological distance to the interviewer was evaluated to be closer in the dim condition. In terms of the degree of satisfaction with the conversation, in the dim condition, the evaluation of two items—“conversation was friendly” and “conversation was valuable”—increased. These results indicate that the dim condition, such as the lowest allowable level of illuminance according to illumination design guidelines, may have a positive effect on the first face-to-face communication.