Just because an analysis of polyphasic sleep has been done by a "scientist" does not mean that it's honestly critical. As a case in point, Steve Pavlina linked to an article in which polyphasic sleepers were refered to as "mutants." What I find most amusing is the claim to know what the long term effects of polyphasic sleep are when there have not been any investigations into its long term effects thus far.
As for the dream, I first thought of Waking Life also because that's the only place I distinctly remember seeing the "light test." In general dream interpretation, when the setting of your dream is in full light, then the dream usually symbolizes something that is in full consciousness in your waking life while a darkly lit dream indicates something that is hidden in your unconscious. Perhaps that would be the reason why you can't change the lighting in your dream as it would alter the symbolism.