FWIW, I looked into this a few months ago. I don't have any cites, but I found some reasonably persuasive articles that light-on-dark is best only for dimly-lit rooms. If you're in a bright office, dark-on-light is best. (And being in a brightly-lit room is probably best for mood and alertness anyway.)
The origins of dark-on-light as "readable" are old-school monochrome computer terminals, where the resolution was so low that if you used light-on-dark, you'd see all the individual pixels - light pixels lit up, dark ones didn't. We're past that now.
The origins of dark-on-light as "readable" are old-school monochrome computer terminals, where the resolution was so low that if you used light-on-dark, you'd see all the individual pixels - light pixels lit up, dark ones didn't. We're past that now.