I feel like this is correct. What do you think? I've never seen geniuses/very reasonable people sunbathing for hours and hours like those "primal" influencers do, worshipping the sun, etc. It seems people's brains work better in the cold. Cold climates definitely increase productivity, and people living in those countries with minimal sunlight often get their vitamin D through diet.
I'm not an expert. I wonder if it also relates to quality of sleep, cooler temperatures provide for better rest. A counter point might highlight that a lack of sunlight based vitamin D increases depression such as occurs in areas of seasonal sunlight deficiency and the S.A.D. phenomenon. Also worth asking if there was a control in place for temperature v sunlight exposure.
Plebscan