The study was performed in a research room (7.0 mL 3 3.6 mW3 2.45 mH) in which the air temperature was automatically maintained at 24 C. Twobooths (Fig. 1) were set up in the room. Each booth (1.8 mL 3 1.8 mW 3 2.45 mH)had a desk, a chair, and a desk lamp (Model: Sampo LH U1001TL; 100 V, 60 Hz, 14W). Black curtains were applied to separate the two booths. Two subjects took theattention test at the same time.