> With artificial light, and no doubt the temporal discipline of the pig system, this all changed. Has anyone else heard this?
Yeah, Cracked Online of all places actually addressed this in one of their lists:
http://www.cracked.com/article_19121_7-basic-things-you-wont-believe-youre-all-doing-wrong.html
Scroll down, it's number 4.
Though of course, they get all normative and shit about it, like we moderns are sleeping "wrong".
Also, tangentially related to this sub-thread, folks might enjoy this article from Endnotes #2, "Sleep Workers Inquiry":
http://endnotes.org.uk/articles/7