But society does not always abide, insisting that people simply go to sleep earlier, and that as long as you get seven hours of sleep or so, you should be fine.

“If your sleep patterns are misaligned with your internal circadian rhythms,” Owens told me, “then that’s going to have a more important impact on self-regulation than how much sleep you actually get at night.”

In the latest research, her team studied high-school and middle-school students in Fairfax County, in Virginia, where the first bell rang at 7:20 a.m. The researchers compared thousands of students, some who were morning people and some who were night people. The results showed that even when everyone got the same amount of sleep, “self-regulation” was worse among night people.

Self-regulation is a psychological construct that comes up a lot in health research. Its absence has been associated with a host of negative outcomes, like substance abuse and depression. Owens explained to me that there are three types of self-regulation: emotional, cognitive, and behavioral. In each of these domains, a person can have stability and control (or at least a sense of control). All three can be lost or improved throughout life, but they’re largely shaped by our environments and behaviors during younger years.

Her takeaway: “It’s not just how much you sleep, it’s when you sleep.”

The research shows a correlation between chronotype and self-regulation, so which element might be causing the other—if the two are indeed related—can’t be said. But taken together with other research on night people and morning people, chronotypes do seem to have serious implications for health and wellbeing—in that they influence our standing in societies. Mismatches with people and systems around us can influence educational attainment and, thus, financial and social stability. So in a world that tends to reward and praise morning people, Owens is interested in mitigating systems that discriminate against people of the night.

For example, as NPR’s Morning Edition reported on Wednesday on this research, a 17-year-old named Zachary Lane has four alarm clocks and still “regularly gets detention for being tardy.” Even when he does make it to school on time, he’s groggy. “I feel kind of like I’m lagging behind myself,” he said. “I don't feel totally there.”

That sounds like a serious sleep disorder. Four alarm clocks is too many. Owens says that kids like Lane suffer as a result of a system they can’t control. Academic difficulty can set off a cascade of low confidence, further lack of self-regulation, health problems, and on and on. All from something that wasn’t the night child’s fault to begin with.

“These kids simply cannot fall asleep much before 11:00 at night,” she told me. “That’s the way their circadian rhythms are wired. They need eight to 10 hours of sleep. So, you can do the math.”