Good article, Markham, and it makes a lot of sense. Having spent time working with sleep disorders, finding the culprit for disruption of circadian rhythms is always the first step. Dark rooms, for instance, are a better climate for sleeping than light ones. Introduce blue light and it must be a problem. I agree it’s more likely to be the activity than the light itself. People who leave their phones on at night deserve what they get. If getting a text message that simply says “LOL” at 3 a.m. is more important than sleeping, why go to bed at all? “No cellphones in the bedroom” is a good rule. “No cellphones in the house” is a good one, too. Step outside to do your texting and make your calls. Once your brain matches communication with the natural elements of freezing cold and boiling heat, cellphone use will decline—and “heater/cooling” apps will go through the roof.