Today I read an interesting article which will shed doubt on all of science. I read today that the cortex generally becomes more aroused as time awake increases. So, the longer you go without sleep the more excitable your brain is, especially the frontal cortex.
What does this mean for science? Well science is the collection of knowledge acquired in various ways, a lot of which comes from experiments involving human subjects. I would almost be willing to bet that 99% of experiments using human participants have worked around the participants schedule and recruited them whenever. So for example, participant A in group A was tested at 7am (awake for 2/3 hours maybe?) and participant B in group B was tested at 4pm (awake for 8/9 hours maybe?).
Why does cortical excitability cause problems? Well, the longer you stay awake the more likely you are to have hallucinations and staying awake for a long time also reduces depressive symptoms. These signs show that the brain undergoes changes the longer you are awake. So the brain of participant A and participant B are naturally different due to different levels of being awake.
Should sleep wake cycle become a demographic question used when recruiting? Probably yes - Will it? Probably not. Why not? well if we researchers worked around our own schedule we would never have volunteers. The best we can do is try to balance groups in the same way we would balance baseline ability. Try.
But yes, this does make me wonder about science as a whole - how many imaging studies have taken data from a large sample without considering this new and scary fact? (maybe in the same way they didn’t look at caffeine baseline? - that’s a whole other kettle though).