Okay so I started doing my research for this whole natural -environment-learning-affective thing (this is a new official subject matter that I have created of course...). So far, I have been unsuccessful in attaching nature to learning ability, however, my questions did lead to many studies on Seasonal Affectiveness Disorder (SAD). This research forced me to have to recall some the brain facts I learned back in Psych 105. So here's a little review:
First of all the centers in the brain that are believed to hold "declarative memory" and possibly spatial memory (orientation) as well are called the Hippocampi (Singular: Hippocampus). They are these two kidney-bean-shaped blobs located inside the temporal lobe (the big one in the middle towards the bottom from the profile view).
The second thing you need to know about is Melatonin (similar to serotonin, the neurotransmitter that makes you feel happy or content) Scientists now think that increasing the amounts of this neurotransmitter in the brain may stunt the progression of Alzheimer's Disease or maybe even reverse them.
Ok so here's what I pieced together. Melatonin secretion is thought to be triggered in the penial glan by light coming in through through the retina (so in sunnier seasons, the retina receives more incoming light). A study at the University of Illinois on lab rats done to observe the corrolation between the functioning of the hippocampi and the level of melatonin showed that rats lacking the melatonin receptors (MT(2) knockouts) displayed more gradual progress in maze tests than those whose receptors were unchanged. Thus, concluding that low levels of melatonin effect the 'potentiation' (effectiveness) of the hippocampi, which as we reviewed before, are responsible for creating new declarative memories (learning).
Now that's pretty technical, but there was also a study done with people that is a bit easier to comprehend. The National Public Health Institute in Finland did a study to test the effects of light and exercise on the people showing signs of depression. I'll skip all the boring details that had to take into the account and give you link at the end if you're interested in the full story. The results were considered successful if the participants decreased their symptoms of depression by 50% according to the Hamilton Depression Rating Scale. Out of 98, 42 ( 5 men, 37 women) had successful results. Yes that is less than half of the participants, but those are only the ones who reached the 50% improvement rating, not the measure of the progress of those who did not quite reach that level. It's some pretty interesting stuff.
I hadn't heard about SAD before I moved to Minnesota, and having painfully survived one and half winters here, I understand how the absence of light can cause depression. However, I was not aware that it may also put a damper on your ability to learn new things. Not good news for Minnesota educators.
Some ways to improve your mood, and maybe your hippocampi potentiation are to go tanning during those darker months. The UV exposure from tanning bulbs is just as effective on your mood as the natural sun. But if your already dark enough, there is a UV bulb thing-a-majigger(you can contact CCHP for the actual name of it) located on the top floor of the library that supposedly helps as well.
For more information or to access the full reports on the above mentioned studies, check out these sites:
Excercise and Light Study:
Search these topics on Wikipedia:
Seasonal Affectiveness Disorder