A recent article by Kimura & al try to uncover the mystery

One of the first things that always come to my mind when I think of Japan is how weird it is. Not in the bad sense, don’t get me wrong, but the cultural shock I fist had when I moved to Japan was simply breathtaking. Young kids going to school alone in the morning, the streetcar of Nagasaki, the DVD rental shops, the ramen shops, and the law that specify the internal temperature of workplaces in both winter and summer. Yes, there is a law for that. Since 2005, in fact, the Japanese Government has “recommended” to set the air conditioners of offices at 20°C during winter and 28°C during summer-times. The law was issued in order to address global warming, but is the temperature ideal for working?

Two women on a street in a Summer day in Japan (Photo by Andre Benz on Unsplash).

What is the ideal room temperature to work efficiently?

In a study recently published in Frontiers in Psychology by Kimura & al. tried to shred the light on what is the impact of room temperature on individuals’ cognitive performances. In their work, the authors relied on on both explicit —subjective ratings of mental workload—, and implicit measures —EEG, Skin conductance level (SCL), and tympanum temperature—. Participants’ engaged in a memory task while the experimenters controlled the temperature of the room (18, 22, 25, and 29°C).

Climate change is one of the most important issues for humanity. To defuse this problem, it is considered necessary to improve energy efficiency, make energy sources cleaner, and reduce energy consumption in urban areas.

Based on previous work on the effect of room temperature on cognitive performances, the author of the current study designed a learning task able to control for both variations in performances due to the changes in the room temperature. Participants (N = 24, 11 females, aged between 20 and 24) were first asked to read a text, memorizing the details of the narrative, then asked to engage in a word recalling task, where words were presented on screen and participants were required to state whether the word was present or not within the text. Reading time, hit rate and response times were used as learning efficiency (the former), and output efficiency (the latter two). Additionally, the working memory levels were assessed using red dots in a five-by-five black grid, using letters are distraction stimuli, while subjective ratings, mental demands, performances, mental workload and frustration where measured using the Japanese version of the NASA-TLK.

Two men at work in their office (Photo by Tim van der Kuip on Unsplash).

Fast forward to the results

Results of the study show that the room temperature does not impair the efficiency of learning, which is instead facilitated by the repetition of the task. Despite that, the mental workload and subjective frustration level increased, while performance, arousal, and subjective valence decreased over time. Moreover, the analysis of the neurophysiological signals revealed specific time-evolution patterns with the change in mental workload and time.

If this sounds complicated, don’t worry, it is. While the authors discuss the implication of the singles measures in their article, here we will focus on the general conclusion that can be drawn from the results. Is there a specific temperature which is better than the other, when it comes to our efficiency at work? From the results of the study here presented we can clearly say no. Since the mental workload changes while we progress on a task, and the temperature of the environment has been proven to affect the mental workload, with higher temperature increasing the cognitive workload, the temperature of the room should be changed accordingly to the perceived mental workload, in order to keep an optimal level and maximize someone’s efficiency.

So if you are stuck at home during this period, you should considering setting a temperature such that you can help the environment (and your utilities), and gradually reduce it when needed to reduce the impact of the temperature on your capabilities.

TL, DR: there is no optimal temperature. Regulate your fan and AirCon accordingly to what you are doing and to your mental workload.

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Source

Kimura, T., Takemura, N., Nakashima, Y., Kobori, H., Nagahara, H., Numao, M., & Shinohara, K. (2020). Warmer Environments Increase Implicit Mental Workload Even If Learning Efficiency Is Enhanced. Frontiers in Psychology, 11, 568.