Thermal preferences and cognitive performance estimation via user's physiological responses
This study investigated the relationship between occupants' thermal sensation, physiological responses, and cognitive performance to quantify the priorities of the selected physiological responses for optimal productivity. In order to quantify variables for optimal productivity estimation, this study considered the following factors: 1. Local body skin temperature as an occupant's physiological responses; 2. Participants' individual factors such as gender; 3. Cognitive performance in operation span task; 4. Environmental data such as indoor temperature, wind velocity, CO2 level and indoor humidity; 5. Individual ratings of subjective thermal sensation. A series of human experiments were conducted to collect physiological responses and cognitive performance in a different room temperature conditions. The skin temperatures and environmental data were recorded in every minutes, and thermal sensation was surveyed by the Likert 7 point scale questionnaires. The operation span (OSPAN) task was used to measure working memory as a cognitive performance for occupant's productivity. Total 39 participants' data was collected for comparative analysis. The results revealed significant correlations between overall thermal sensation and local body skin temperatures. Also, the OSPAN score showed that it has a significant correlation with indoor temperature, thermal sensation as well as physiological responses. The OSPAN results were higher when indoor temperature was relatively low or when participant's thermal perception was either slightly cool or cool. Most local body skin temperatures were negatively correlated with the cognitive test scores, therefore it was concluded that a little low temperature has a significant impact to promote occupant's productivity. This study also determined the priority of local skin temperatures and gender by their impact to estimate the occupant's cognitive performance.