Electroencephalograph (EEG) Insights into Short-Term Thermal Adaptation and Alliesthesia: From Rapid Change to Steady State

• Investigates short-term thermal adaptation and alliesthesia using EEG. • Short-term adaptation occurs within 15-16 minutes. • Identifies two phases of short-term adaptation: rapid response and stabilization. • Finds distinct EEG signatures for warm (positive) and cool (negative) alliesthesia. • Highlights the complex interaction between alliesthesia and short-term adaptation. This study investigates two underexplored aspects of dynamic thermal comfort—short-term thermal adaptation and alliesthesia—using electroencephalography (EEG). Participants, in a within-subject experimental design, experienced controlled transitions between neutral, warm, and cool thermal states in a climate chamber. A total of 32 experimental sessions were analyzed for short-term thermal adaptation, with a comparable dataset examined for alliesthesia. Robustness was ensured through validation analyses for both studies. Over the 20-minute observation period, short-term thermal adaptation was observed to occur over 15–16 minutes, progressing through two distinct phases: an initial rapid response phase (1–4/5 minutes) and a stabilization phase (4/5–15/16 minutes), before entering the steady-state phase (beyond 15/16 minutes). Each phase exhibited unique patterns of EEG activity, providing a detailed understanding of the neural mechanisms underlying adaptation across different thermal conditions. Additionally, the study offers novel insights into the dynamics of thermal alliesthesia. EEG analysis identified both common and distinct neural signatures for warm (positive) and cool (negative) alliesthesia. Notably, the effects of alliesthesia were most pronounced during the stabilization phase of short-term adaptation (the second 5 minutes), as the initial response phase began to diminish. This finding underscores the complex interplay between alliesthesia and the processes of thermal adaptation. These results provide critical insights into the neural mechanisms of thermal perception, with significant implications for the design of adaptive environments. By integrating real-time physiological responses into environmental controls, such designs have the potential to enhance occupant comfort, improve energy efficiency, and promote sustainability in the built environment.