Subjective experiments on relationships between indoor environment and arousal state and between arousal state and work performance

The present study focused on arousal as one of the human physiological and psychological responses mediating the causal relationship between indoor environmental quality and performance. In order to investigate the role of arousal state, two subjective experiments were carried out. The first experiment was to verify that indoor environment affects occupants’ arousal state. Indoor temperature, outdoor air supply rate and illumination intensity were changed at two or three levels (22, 25, 28^oC; 10, 30 m³/h/person; 10, 300 lx), and six combinations of them were adopted as the experimental cases. A questionnaire was used to evaluate their arousal state with two dimensions of energetic arousal (EA) and tense arousal (TA). Skin conductance level was also used for objective assessment of their arousal state. As a result, EA tended to be low in the cases of poor IEQ, while TA tended to be high at the same time. The second experiment was to verify that arousal state affects performance. During the experiment, subjects performed three types of tasks (detecting wrong pairs of numbers, inputting numbers, and Sudoku), and indoor environment was not controlled. This experiment showed that subjects’ performance became higher when EA was high, but became lower when TA was high.