Lighting design for enclosed environments: A multimodal predictive framework for human alertness and emotional responses

Lighting in enclosed, daylight-isolated environments must simultaneously sustain alertness and emotional stability, yet current standards provide limited guidance for achieving both outcomes. This study presents a multimodal predictive framework for preventive lighting design based on emotion–alertness integration. Twenty combinations of illuminance and correlated color temperature were evaluated in a windowless control-room mock-up using EEG, behavioral tasks, and valence–arousal self-reports. Results revealed two distinct functional regions: higher illuminance with mid-to-high correlated color temperature enhanced alertness and performance, whereas lower illuminance with warmer color temperature promoted calmer and more positive affect. A back-propagation neural network predicted subjective alertness and valence from selected EEG and behavioral response features recorded under each lighting condition, and the resulting response patterns were used to map design-relevant lighting regions. The framework provides a direct pathway from multimodal evidence to parameterized lighting decisions, supporting preventive, health-oriented design in enclosed habitats.