“Night owl” does not describe some innate biological reality. It’s a matter of preference and habit.

To the contrary, there are genetic changes that correlate to different chronotypes [0]. I find interesting the hypothesis that chronotypes arose as a survival advantage because tribes could more naturally sleep in shifts to stay safe during the night time. I do think, however, the genetic component is overstated. I agree with you that it is more habit than anything, and lifestyle.

We as a society should do more research to determine how large the habit versus genetic components are, or publicize the information and act on it more if it is out there already. If we are fighting an unwinnable battle trying to adjust people in opposition to their genetics, we should change our practices. Similarly, if we are instilling a defeatist mindset into people (e.g. “I can’t do that, I’m not an early bird”) which cannot be justified by science, we should change our perception.

[0]: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6084759/

The fact it’s called a correlation shows it is not a fact that there are biological night owls.

And it shows that it’s not a fact that there are not.

In this case the correlation is due to a causal relationship between genetic variation and chronotype that is well established. The roles of many of the genes involved have been established in lab organisms -- fruit flys and mice mostly -- yes you can observe and manipulate chronotype in flys. The same circadian rhythm genes have similar functions in people. There are rare mutations in these genes that cause familial sleep disruption syndromes, as well as common variants that have small effects that can be detected in large studies.

I think with genetic sequencing we’re way past this belief.

We are not. There are some suggestions that they might be biological but it is not a settled matter at all.

It is absolutely settled. The genetic basis of chronotype has been extensively studied in fruit flys and mice, and parallel effects in the same genes have been found in humans.

I'm not sure that's true, at least based on personal experience. I'm a long-time night owl who has been getting up relatively early for work purposes the last couple of years. I still do my best work late at night and struggle a little on complex tasks before noon.

It seems like, while I can adjust my sleep schedule to whatever, the actual cycles of alertness have their own schedule that doesn't want to move.

Without a clear biochemical pathway (or an absence of) that's just an opinion, as weak as most the the current research in humanities.

This is false, the biological pathways that underly circadian rhythms have been mapped out in great detail in multiple organisms.

I think there's a lot to be said for habits swaying it but I think "biological" night-owl-ism is definitely a thing.

I've always been a night owl. The most in-tune I've ever felt with my biological clock is when, one summer in college, I ended up going to bed at 5-6am and waking up around 3-4pm. I had friends on IRC who lived in new zealand who I ran a minecraft server with and did minecraft plugin coding with (enabled by the weird sleep cycle, not caused by it).

College and school etc always had me feeling exhausted. I maintain that I must have some innate mathematical ability because my 7:30 AM algebra 2 class in high school was performed exclusively by my subconscious as my brain got an extra hour of sleep regardless of what the external world was trying to impose upon it.

Anyway, blah blah night owl, then I had kids. Both the father and mother have a lot of hormonal changes (obviously the mother moreso but it's still nontrivial for the father) and all of a sudden I was able to wake up with the baby at 6:30am after 7 hours of shitty sleep with relatively no problem. Where was this in high school?? Well, the sleep part, not the baby part. But I digress.

Baby becomes toddler and start sleeping 10-12 hours at night, hormones recede, normalcy restores, and suddenly waking up to go to work at even 9am resumes being mild-to-moderately painful.

Have next baby. Cycle repeats.

Currently typing this having gotten up at 7 with baby #3 so this is top of mind.

This is total speculation on my part, but it seems like there would be a strong evolutionary pressure, at a group level, to select for a mixture of night owls and early risers. The "night owls" stay up to watch for predators to keep the group safe. Those groups without some late sleeper DNA ultimately get selected out.

BINGO.

There are probably some genetic night-owls or something, but I bet 95+% of night owls would be "cured" in a week flat if they were allowed no glowing screens past sundown and their typical stupid-bright room lighting were replaced with warm-temp handheld lights at ~2-4 candle equivalent (actual, not "candle power")

Modern sleeplessness is an epidemic born of hyper-palatable on-tap nigh-infinite entertainment, and far-too-bright nighttime lighting, more than anything else. It's mainly due to how incredibly stimulating our home environments are now, unprecedented ever before. Even an emperor didn't have this kind of entertainment available 24/7 on a whim—the closest equivalent would be an emperor in the middle of hosting a huge, expensive festival, but we've got that at our fingertips every hour of every day. No fucking wonder we can't sleep!

I usually sleep 9h from 3 to 12.

But, when I was on a conference last year, where I had to get up early for events for a whole week, my rythm changed and I slept from 12 to 9.

This kept going on for two weeks or so, then I was back to my old schedule.

> I bet 95+% of night owls would be "cured" in a week flat if they were allowed no glowing screens past sundown and their typical stupid-bright room lighting were replaced with warm-temp handheld lights at ~2-4 candle equivalent (actual, not "candle power")

It's an interesting theory. Problem is, without a biochemical pathway it means nothing.

Melatonin secretion & basal temperatures are both interesting avenues for research. Blue light seems to be a favorite as well.

It's not all biochemistry, much of it's psychology. Unless we're going with "psychology is just biochemistry".

I get where you are going, but there are a few issues with this, the first being that no screens after sundown is a wildly unreasonable ask in 2023 (especially for the types of folks who frequent this board), at least in my opinion. A lot of the talk around screen time before bed also fails to factor the type of activity being done on the screen, and what type of screen is being used. Shopping on your laptop vs reading on a fully dimmed phone screen are entirely different ends of the spectrum in terms of stimulation and significantly different in terms of light emitted and screen motion

That said, I’ve found switching to warm dimming circadian lighting at night has been a huge help and is an easy enough solution

A better question is: why is this something that needs to be cured? Why cater society's schedule to people who wake up at "too fucking early" O'clock, instead of either A) having flexible hours for jobs that support it (There's no reason why my office needs to have everyone work the same 8 hours), or B) a middle ground that doesn't involve grating against the preferred sleep schedule of a significant portion of the population.

Somehow we let society moralize "the early risers are Gods chosen people" and the rest of us just need to put up with it.

I wonder what role widespread caffeine consumption has to play in this.

This is somewhat along the lines of my current theory, which is that night owls vs early birds is about sensitivity to the environment. The reason night owls stay up late is not because it's late, but because it becomes quiet enough that the environment they're sensitive to stops taking attention and the person can direct that attention inward. According to this theory, it would make sense for introverts to be more affected by this as they would accumulate an "introversion deficit" throughout the day.