I'm the source. It's a personal "study" of my own behavior and IQ.

My wife stays up to the same time, sleeps late, and has not shown the same decrease in IQ.

But, here are a few mentions of study results on lack of sleep causing lower IQ and light keeping people awake:

http://www.cbc.ca/health/story/1999/03/20/sleep990320.html

http://www.livescience.com/health/teens-sleep-morning-light-...

And here are some alarm clocks that wake people up with light:

http://www.amazon.com/s/ref=nb_sb_noss?url=search-alias%3Dap...