Lighting effects on visual and cognitive adaptation in multimedia classrooms: a multimodal neurophysiological study

Classroom lighting influences both visual comfort and cognitive performance, yet its neurophysiological mechanisms remain underexplored in real-world educational environments. This study systematically compared typical daylight and artificial lighting to examine their effects on visual load, attentional regulation, and cortical activation during screen-based learning tasks. Experiments were conducted with forty-one university students in LED-equipped multimedia classrooms. Participants completed two cognitive tasks—2-back (numerical working memory) and Stroop (color recognition)—under each lighting condition. Visual behavior was measured using high-resolution eye tracking, neural activity was recorded with functional near-infrared spectroscopy, and subjective comfort was assessed through questionnaires. Key outcome measures included pupil diameter, eye fixation duration, prefrontal cortical activation, and the ratio of oxygenated to deoxygenated hemoglobin. Daylight was associated with smaller pupil diameters, shorter eye fixation durations, and more localized prefrontal activation, indicating reduced perceptual strain and greater neural efficiency. In contrast, artificial lighting elicited broader cortical recruitment and higher oxygenation ratios, reflecting increased neural regulatory load without improving subjective comfort. Neural activation patterns revealed a task-dependent trade-off: daylight supported efficient processing under low cognitive load, whereas artificial lighting provided a more stable visual environment that sustained performance under high cognitive load. These findings advance the multimodal evaluation of visual–cognitive adaptation in educational spaces and offer an empirical basis for adaptive, human-centric lighting strategies that integrate environmental stability with cognitive performance requirements.