

Just realized that even if there is no mechanism to get the exact date from any of these age tracking systems, they’ll be able to infer the exact dates by just looking at when the user/device transitions to the next bracket. Then they’ll know the birthday for the start of that bracket falls somewhere between the last check and the current one.
Though maybe that data can be poisoned by making it transition backwards occasionally, so it looks like the user is editing their age older and back or something. But, on the other hand, a lack of data or poisoned data is going to be a flag on its own at some point (if not already).




The reason that 25 number came up is that’s how old the cohort they were studying brain development got when their funding was cut. There’s no reason to not believe brains continue developing all our lives, or that even if that study did find a “cut off point” that it would be the same from person to person.