Making Sense of Our Surroundings: A Study of Environmental Temperature Across Perception, Multisensoriality, and Social Behaviour

Our perception of temperature is not only a matter of physics: it shapes how we feel, think, and even behave around others. While previous research has mostly focused on how single body parts detect localised temperature changes, improving our understanding of the physiological and neurological basis of thermal sensing, no study with a similar methodological approach had investigated our ability to perceive ambient temperature at the whole-body level. This PhD thesis aimed to explore precisely that: how humans perceive environmental temperature in both unisensory and multisensory contexts, and how it may influence social behaviour. Across four experimental studies involving over 200 participants and using climate chambers for precise thermal simulation, we assessed human sensitivity to environmental temperature and its behavioural implications. Specifically, we measured environmental temperature sensitivity thresholds to neutral (24 ± 1 °C), mild (18 ± 1 °C and 28 ± 1 °C), and extreme (8 ± 2 °C and 38 ± 2 °C) environmental temperatures, assessed thermal perception in multisensory contexts involving visual cues (red and blue lights), and explored the influence of physical and visually simulated temperature on interpersonal space (IPS). Results revealed a remarkable baseline sensitivity to temperature changes under neutral and mild conditions (0.38 °C < JND < 0.45 °C), with reduced precision under extremes (0.80 °C < JND < 0.95 °C), likely due to both cognitive resource reallocation and thermoreceptor limitations. Moreover, we found that visual cues (colour-temperature associations) consistently interfered with thermal perception (0.51 °C < JND < 0.67 °C), with individual differences suggesting variable cross-modal integration strategies. Finally, we discovered that environmental temperature modulates IPS in a gender-specific manner: hot conditions increase IPS (of ~10%) in men but not in women. Notably, we found similar, though weaker, effects via a visual-only stimulation in virtual reality (increase of ~3%). Taken together, these findings show that our perception of environmental temperature is precise yet flexible, shaped not only by the physical properties of the stimulus but also by context, expectations, and social factors. Temperature is not just sensed; it is interpreted. It functions as both a biological signal and a social one. In conclusion, the work presented in this thesis invites us to rethink perception not as a reflection of the outside world, but as an active process through which the body and mind make sense of their environment.