Light and Motion: Effects of Light Conditions and mEDI on Activity and Motion Area under a Sky-Lighting Machine

Abstract

ABSTRACT We investigated whether differences in light levels and spectral properties have effects on motion. Twenty-two participants, divided into groups of two, experienced the same room in two diffused light conditions (daylight [DL] or static artificial light [AL]), which were experienced in a repeated measures design layout, controlled for order. Both light conditions offered a stimulus of at least 250 melanopic equivalent daylight illuminance (mEDI) lux, without a view. Participants were observed during an individual reading session and a collaborative construction game session. We measured the connectivity of the built structures, activity by actigraphy, and we automatically extracted motion area and quantity of motion from video analysis. We found a correlation between mEDI values in the two light conditions (DL or AL) and activity and a correlation between light condition and motion area. Diffuse daylight conditions were correlated with lower activity and less extended motion than a diffuse static condition at levels recommended for office lighting and to ensure alerting responses. Indeed, static AL was found to be related to increased spatial exploration, which might indicate restlessness, and high mEDI to a more composed motion. Actigraphy measurements correlate with quantity of motion values; therefore, the two methods provided comparable results. Results also showed a high correlation between all photometric values in the daylight condition. These findings offer arguments for favoring DL conditions in the design of places where it is desirable to avoid fidgetiness, like educational institutions, and to support composed motion, like medical institutions.