Do coloring books say anything about children?

Was there ever some study done on this? Was there ever a legitimate reason to make such a study, and did it justify itself?

Like, if a kid colors outside the lines and fails to respect the boundaries given by the coloring book, are they going to be a rebel? Do they like to be funny, and are they just having a blast? If they color ON the outline and then carefully fill in the rest with the same color, but a little paler than what they did with the outline, does that mean they might be closed minded? Or perhaps they have admiration for rules and order? What if they just draw horns and vampire fangs on heads? Are they messed up in the head, or just immature? Or creative, perhaps? Or discontent?
If they add their own drawings outside of the coloring book’s original drawing, does it mean they might be selfish, or does it mean they have a bigger view of things? What if they refuse to color? What does it mean if they color everything with the SAME color?

Or, perhaps, if there’s some psychological legitimacy to kids and coloring books, it’s a lot more complicated than what my details are suggesting. Something subconscious, or the complete contrary? Or perhaps it means nothing at all. Thoughts? Facts? pillows? I’d be interested to know.

Additional; And what the hell does it mean if a grown up adult with a job, a family and a big fancy car secretly likes to color in coloring books?