quackery indeed. I've read a little about this in the past. Many here likely notice now and then how people say in posts here how someone's reaction to tickling was "oh, that's childish/kid's stuff." That actually once was mainstream scientific dogma, that tickling was something you shake when you become an adult----and if you don't, it means you're either full of angst, neuroses, or other psychological conditions that make you overly sensitive to stimuli. Goofy shit like that. Of course, as people noted, some have bad memories of abusive tickling growing up, but this is more broad, linking ticklishness with psychological health. They showed a Johnny Carson rerun from the '70s recently, with a creepy-ass psychologist on, who said he would be invited to schools to test children for psychological conditions through ticklishness, that the more ticklish, the more neurotic or otherwise angst-ridden the kid was.