Rainy Days

As I mentioned in a previous post, when it rained hunter-gatherers stayed close to the base and were not as active as they were on sunny days.  I wonder if that over time, a physiological response to rain was built into the human body (and mind).  What this means is that the appearance of rain would put an "automatic" damper on one's mood and physical energy levels.

It would be easy for this to have evolved over time.  After all, if there's no game to be found when it's raining, the smart hunter-gatherers stayed in. 

So maybe rainy days leave people feeling blue for different reasons than they think.  Maybe it's not because your shoes will get wet and your hair will get messed up, but it's because your physiology is telling you that prospects aren't good today, and you shouldn't get your hopes too high.