Having a mother who lived within 1,000 feet of a freeway while pregnant doubles a child's odds of having autism [1].
Basically, white noise can cause autism. People are screwing up their kids at an exponential rate [2].
[0]: https://web.archive.org/web/20210609042055/https://www.latim...
[1]: https://www.webmd.com/brain/autism/news/20101217/fast-lane-t...
[2]: https://www.google.com/search?client=firefox-b-1-d&q=childre...
It seemed to me nearly all of it was correlative. Which is fine, as it may be true.
But very few corrected for the fact freeways often run through the worst areas in town, which could mean nutrition, drugs, alcohol, lead paint, asbestos, heck about anything else bad about living in older, run down areas.
Would be interested to see if those show the same.
If not, you could rule out white noise completely. That would then seem to point to other factors, including total pollution, or more socioeconomic things.
I was a strange child that could only sleep if mother turned on a hair dryer next to me some nights. This is materially different from highways - I briefly got to experience what it was like living next to a noisy road and I would argue it would be more likely that it is the role of noisy cars, screeching tires, horns, and pollution that is at play in these studies, not the white noise of highways. Would children that lived in windy forests with no sound isolation having to listen to the noise of the trees fare the same?
Most autistic people are sensitive to stimuli - sensitivity being nearly completely genetic determined and little to do with environment. I wonder if it this greater sensitivity being triggered by highways and disturbs sleep that impairs brain development.
Though, what's more likely is that a child with mild ASD is more obviously autistic under stress, which leads to diagnosis earlier.
But the same theory could apply, as health-induced stress instead of distraction stress. Or both.
Also, I'd say that modern children programming that's optimized for grabbing as much attention as possible isn't exactly autism friendly; I find older cartoons with their slower pacing much more comfortable to watch.
"White noise causes autism" is a pretty weird conclusion to get from all of that and would require extraordinary evidence to support it.
edit/ Having said that, the "white noise" machines that I've seen, which are available as sleep aides specifically for young children, are not really white noise. There is white noise there but there is also something that sounds like a tumbling drying machine, or a fan, or a hair dryer... Something that a brain could attach itself to as a pattern.
This lead to me having a recurring nightmare which I also got for a long time into adulthood, seeing the tone as 1/2D line, flowing along nicely, and then the static would screw it up and turn it to knots and I would be unsuccessful in making it turn back to a line.
In a way perhaps it's kind of an abstract "powerlessness in the face of chaos" nightmare.
Not sure why exactly it went away. But I do remember being conscious of it in my 20s and trying to understand it. I think I tried to understand it consciously and accept some of the powerlessness perhaps. Or maybe later on, it was meaning general confusion and anxiety which was suppressed.
At any rate the nightmare was very scary and awful, as if something evil and wrong was there.