I messed with my experiment by accident yesterday.
I sat down around noon to begin writing the literature review portion of my dissertation prospectus (a heady endeavor to be sure), and next thing I knew, there was a pile of dishes I don't remember creating, and the sun had gone down - but I hadn't turned down the lights as the sun set.
I suspect the reason I forgot to turn the lights off was because I was completely unaware that I should be getting tired because I was otherwise occupied. It could also be because I was busy consulting actual, physical texts, and candlelight would not have been conducive to massive text consultation.
I noticed two things, as soon as I figured out the sun had gone down:
1. Electric light absolutely has an effect on my ability to get tired.
2. I can decide whether or not to be tired - at least I can when I'm regularly getting enough sleep.
I went to sleep last night the latest I have yet - at 10:39PM. And according to Benjamin Franklin, I was being rather ill-behaved. Even so, I woke up just after 8AM, so my body didn't try to make up for the lost hour, as I suspected it would.
Tonight though, I am back to candlelight, and yet... not tired again. I have about 3 day to get to the bottom of this. Perhaps it's because I get energized when I'm having long writing days. Perhaps it is something else entirely.