An investigation of humans’ sensitivity to environmental temperature

The grounded cognition theory assumes that the human mind must be studied in conjunction with the body and the surrounding environment. In particular, this theory posits that cognition is a result of the combination of multisensory processes, bodily states and interactions with the environment. Naturally, the space surrounding us is characterised by a lot of different aspects, such as the amount of vegetation, relative humidity, temperature. Given the extensive research that has already been conducted to investigate our sensitivity to thermal stimuli directly applied to our body, we decided to study our sensitivity to environmental temperature. This represents an unexplored research field and we aim to understand how much the temperature of the surrounding might affect various psychological dimensions, such as our body representation and our perception of space. In order to define humans' sensitivity to environmental temperature, we adopt an experimental paradigm as close as possible to a staircase procedure by manipulating temperature in a very controlled fashion inside four climate chambers. Participants move between these chambers making comparisons between the temperature of two chambers per time. Specifically, their task is to report whether the second chamber they entered is warmer or colder than the first one. Inside the chambers, the temperature continuously changes between 23°C and 25°C. This temperature range was defined thanks to a pilot experiment. The procedure takes one hour and forty minutes for a total amount of one hundred and twenty comparisons. The results are analysed in order to build the psychometric function defining participants' sensitivity. In particular, we plot their probability of answering warmer as a function of the real differences in temperature. The standard deviation of the final psychometric curve can be conceptualised as the just noticeable difference participants were able to perceive. The preliminary results indicate that the average participants' sensitivity is half a degree. Such a result is of relevance not only for the planning of our next experiments but also from a more ecological perspective (e.g., it could be relevant to arguments such as heating and cooling). In particular, possible follow-up of this research could investigate which factors may affect our sensitivity and enlarge our comfort temperature range. Another possible future research could try to understand better the physiological and psychological aspects that lead to such great sensitivity. For instance, further studies might investigate whether the amount of skin exposed to the environment is relevant to its perception or whether more cognitive strategies, such as visualising a scenario congruent to each temperature, can increase or decrease our sensitivity.